Horticulturae

16 pages, 1803 KiB

Open AccessEditor’s ChoiceArticle

Integrative Effects of CO₂ Concentration, Illumination Intensity and Air Speed on the Growth, Gas Exchange and Light Use Efficiency of Lettuce Plants Grown under Artificial Lighting

by Hesham A. Ahmed, Yuxin Tong, Lie Li, Suliaman Q. Sahari, Abdulkarem M. Almogahed and Ruifeng Cheng

Horticulturae 2022, 8(3), 270; https://doi.org/10.3390/horticulturae8030270 - 20 Mar 2022

Cited by 6 | Viewed by 3253

Abstract

This study investigates and quantifies the integrative effects of CO₂ concentration (500, 1000 and 1500 µmol mol⁻¹), illumination intensity (100, 200 and 300 μmol m⁻² s⁻¹) and air speed (0.25, 0.50 and 0.75 m s⁻¹) [...] Read more.

This study investigates and quantifies the integrative effects of CO₂ concentration (500, 1000 and 1500 µmol mol⁻¹), illumination intensity (100, 200 and 300 μmol m⁻² s⁻¹) and air speed (0.25, 0.50 and 0.75 m s⁻¹) on the growth, gas exchange and light use efficiency of lettuce plants (Lactuca sativa L.) grown under artificial lighting. The results show that lettuce growth and gas exchange are closely related to CO₂ concentration and illumination intensity, while air speed enhances CO₂ transport during photosynthesis. The most influential two-way interactions were observed between CO₂ concentration and illumination intensity on the fresh and dry weights of lettuce shoots with effect sizes of 34% and 32%, respectively, and on the photosynthesis, transpiration and light use efficiency, with effect sizes of 52%, 47% and 41%, respectively. The most significant three-way interaction was observed for the photosynthetic rate, with an effect size of 51%. In general, the fresh and dry weights of lettuce plants increased by 36.2% and 20.1%, respectively, with an increase in CO₂ concentration from 500 to 1500 µmol mol⁻¹ and by 48.9% and 58.6%, respectively, with an increase in illumination intensity from 100 to 300 μmol m⁻² s⁻¹. The photosynthetic rate was found to be positively correlated with CO₂ concentration, illumination intensity and air speed. The transpiration rate and stomatal conductance increased by 34.9% and 42.1%, respectively, when the illumination intensity increased from 100 to 300 μmol m⁻² s⁻¹. However, as CO₂ concentration increased from 500 to 1500 μmol mol⁻¹ and air speed increased from 0.25 to 0.75 m s⁻¹, the transpiration rate decreased by 17.5% and 12.8%, respectively. With the quantified data obtained, we were able to adequately determine how CO₂ concentration, illumination intensity and air speed interact with their combined effects on the growth of lettuce plants grown in indoor cultivation systems with artificial lighting. Full article

(This article belongs to the Section Vegetable Production Systems)

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20 pages, 5053 KiB

Open AccessEditor’s ChoiceArticle

VIS-NIR Modeling of Hydrangenol and Phyllodulcin Contents in Tea-Hortensia (Hydrangea macrophylla subsp. serrata)

by Marcel Dieter Moll, Liane Kahlert, Egon Gross, Esther-Corinna Schwarze, Maria Blings, Silke Hillebrand, Jakob Ley, Thorsten Kraska and Ralf Pude

Horticulturae 2022, 8(3), 264; https://doi.org/10.3390/horticulturae8030264 - 18 Mar 2022

Cited by 3 | Viewed by 2370

Abstract

Hyperspectral data are commonly used for the fast and inexpensive quantification of plant constituent estimation and quality control as well as in research and development applications. Based on chemical analysis, different models for dihydroisocoumarins (DHCs), namely hydrangenol (HG) and phyllodulcin (PD), were built [...] Read more.

Hyperspectral data are commonly used for the fast and inexpensive quantification of plant constituent estimation and quality control as well as in research and development applications. Based on chemical analysis, different models for dihydroisocoumarins (DHCs), namely hydrangenol (HG) and phyllodulcin (PD), were built using a partial least squares regression (PLSR). While HG is common in Hydrangea macrophylla, PD only occurs in cultivars of Hydrangea macrophylla subsp. serrata, also known as ‘tea-hortensia’. PD content varies significantly over the course of the growing period. For maximizing yield, a targeted estimation of PD content is needed. Nowadays, DHC contents are determined via UPLC, a time-consuming and a destructive method. In this research article we investigated PLSR-based models for HG and PD using three different spectrometers. Two separate trials were conducted to test for model quality. Measurement conditions, namely fresh or dried leaves and black or white background, did not influence model quality. While highly accurate modeling of HG and PD for single plants was not possible, the determination of the mean content on a larger scale was successful. The results of this study show that hyperspectral modeling as a decision support for farmers is feasible and provides accurate results on a field scale. Full article

(This article belongs to the Special Issue Botany, Phytochemistry and Pharmacology in Traditional Herbal Medicine)

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16 pages, 3090 KiB

Open AccessEditor’s ChoiceArticle

Commercial Potato Cultivars Exhibit Distinct Susceptibility to the Root Lesion Nematode Pratylenchus penetrans

by Joana Figueiredo, Paulo Vieira, Isabel Abrantes and Ivânia Esteves

Horticulturae 2022, 8(3), 244; https://doi.org/10.3390/horticulturae8030244 - 12 Mar 2022

Cited by 2 | Viewed by 2596

Abstract

The root lesion nematode Pratylenchus penetrans is an important plant-parasitic nematode of potato. In this study, the susceptibility of commercial potato cultivars to P. penetrans was assessed. Nematode penetration was evaluated in cultivars Agria, Camel, Kennebec, Laura, Royata, and Stemster at 1, 3, [...] Read more.

The root lesion nematode Pratylenchus penetrans is an important plant-parasitic nematode of potato. In this study, the susceptibility of commercial potato cultivars to P. penetrans was assessed. Nematode penetration was evaluated in cultivars Agria, Camel, Kennebec, Laura, Royata, and Stemster at 1, 3, 7, and 15 days after inoculation (DAI) with 750 nematodes/plant, and an egression assay at 3 DAI with 1000 nematodes/plant. Reproduction assays of cultivars Agata, Agria, Camel, Désirée, Dirosso, Kennebec, Laura, Picasso, Royata, and Stemster were performed in 2 L pots inoculated with four P. penetrans/g soil and quantified at 60 DAI. Tenue or moderate root cell browning to advanced necrotic areas were observed after nematode penetration, and the number of nematodes/g of root gradually increased with time of infection. A lower number of deposited eggs and nematodes were observed within the roots of cultivar Laura in all assays comparatively to other cultivars. The susceptibility index (SI) was significantly lower in cultivar Laura (0.4–0.6), followed by cultivars Camel and Picasso (0.8–0.9). All remaining cultivars showed SI values above 1. Although the potato susceptibility to the nematode varied among cultivars, no differences on the average number or weight of tubers produced by each plant of inoculated versus non-inoculated plants were detected. Our data reveals that these cultivars have a distinct ability to support the reproduction of P. penetrans. Full article

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15 pages, 2364 KiB

Open AccessEditor’s ChoiceArticle

A Multicultivar Approach for Grape Bunch Weight Estimation Using Image Analysis

by Gonçalo Victorino, Carlos Poblete-Echeverría and Carlos M. Lopes

Horticulturae 2022, 8(3), 233; https://doi.org/10.3390/horticulturae8030233 - 8 Mar 2022

Cited by 2 | Viewed by 2625

Abstract

The determination of bunch features that are relevant for bunch weight estimation is an important step in automatic vineyard yield estimation using image analysis. The conversion of 2D image features into mass can be highly dependent on grapevine cultivar, as the bunch morphology [...] Read more.

The determination of bunch features that are relevant for bunch weight estimation is an important step in automatic vineyard yield estimation using image analysis. The conversion of 2D image features into mass can be highly dependent on grapevine cultivar, as the bunch morphology varies greatly. This paper aims to explore the relationships between bunch weight and bunch features obtained from image analysis considering a multicultivar approach. A set of 192 bunches from four cultivars, collected at sites located in Portugal and South Africa, were imaged using a conventional digital RGB camera, followed by image analysis, where several bunch features were extracted, along with physical measurements performed in laboratory conditions. Image data features were explored as predictors of bunch weight, individually and in a multiple stepwise regression analysis, which were then tested on 37% of the data. The results show that the variables bunch area and visible berries are good predictors of bunch weight (R² ranging from 0.72 to 0.90); however, the simple regression lines fitted between these predictors and the response variable presented significantly different slopes among cultivars, indicating cultivar dependency. The elected multiple regression model used a combination of four variables: bunch area, bunch perimeter, visible berry number, and average berry area. The regression analysis between the actual and estimated bunch weight yielded a R² = 0.91 on the test set. Our results are an important step towards automatic yield estimation in the vineyard, as they increase the possibility of applying image-based approaches using a generalized model, independent of the cultivar. Full article

(This article belongs to the Special Issue Advances in Viticulture Production)

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13 pages, 2250 KiB

Open AccessEditor’s ChoiceArticle

Decreased Solution pH and Increased K⁺ Uptake Are Related to Ammonium Tolerance in Hydroponically Cultured Plants

by Jinnan Song, Jingli Yang and Byoung Ryong Jeong

Horticulturae 2022, 8(3), 228; https://doi.org/10.3390/horticulturae8030228 - 7 Mar 2022

Cited by 4 | Viewed by 2397

Abstract

The ammonium (NH₄⁺) tolerance of plants is an important issue in agriculture, associated with several plant characteristics. So far, plant tissue acidification has been shown as the primary cause of NH₄⁺ toxicity. Suppressed plant growth caused by excess [...] Read more.

The ammonium (NH₄⁺) tolerance of plants is an important issue in agriculture, associated with several plant characteristics. So far, plant tissue acidification has been shown as the primary cause of NH₄⁺ toxicity. Suppressed plant growth caused by excess NH₄⁺ can be counteracted by potassium (K⁺) application. However, the effects of NH₄⁺ tolerances on the differences regarding pH changes together with K⁺ uptake remain to be determined. Here, we performed an 84 h hydroponic cultivation of five species with different NH₄⁺ tolerances, subjected to three NH₄⁺:NO₃⁻ solutions (0:100, 50:50, or 100:0), to investigate the pH changes and ion uptakes. Consequently, the solution pH was lowered over time to varying extents in the presence of NH₄⁺. The NH₄⁺-tolerant ageratum and lettuce, shown to be tolerant to NH₄⁺ in this trial, rapidly lowered the solution pH, whereas extremely NH₄⁺-sensitive salvia and cabbage only gave a minor decrease in the solution pH when grown with 100:0 NH₄⁺:NO₃⁻. Additionally, the increased external NH₄⁺ level led to a substantial decline in the net cation influxes (K⁺, Ca²⁺, and Mg²⁺). As compared to solely NH₄⁺-fed salvia and cabbage, solely NH₄⁺-fed ageratum and lettuce ultimately showed a relatively greater net K⁺ influx. Taken together, this study discusses how the decreases in pH and K⁺ are related to NH₄⁺ tolerance in five hydroponically cultured species. Full article

(This article belongs to the Special Issue Strategies and Practices of Fertilization Management of Horticultural Crops)

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12 pages, 3281 KiB

Open AccessEditor’s ChoiceArticle

Microalga Biofertilizer Triggers Metabolic Changes Improving Onion Growth and Yield

by Ely Cristina Negrelli Cordeiro, Átila Francisco Mógor, Juliana de Oliveira Amatussi, Gilda Mógor, Gabriel Bocchetti de Lara and Harielly Marianne Costa Marques

Horticulturae 2022, 8(3), 223; https://doi.org/10.3390/horticulturae8030223 - 4 Mar 2022

Cited by 5 | Viewed by 2570

Abstract

Seeking the development of nature-friendly agronomic techniques, the use of natural sources to promote plant growth and increase agricultural yield has gained relevance. In this context, the use of biofertilizers or biostimulants obtained from microalgae has been studied, as these microorganisms have in [...] Read more.

Seeking the development of nature-friendly agronomic techniques, the use of natural sources to promote plant growth and increase agricultural yield has gained relevance. In this context, the use of biofertilizers or biostimulants obtained from microalgae has been studied, as these microorganisms have in their composition a great diversity of bioactive molecules. This study aimed to evaluate the effect of microalga Asterarcys quadricellulare (CCAP 294/1) on organic onion production, verifying its action on metabolism, growth and yield of two cultivars. Thus, two experiments were carried out: (i) foliar applications on onion plants grown in pots in a greenhouse; (ii) foliar applications on field-grown onion under an organic system. Both experiments were undertaken using solutions with spray-dried microalga biomass at concentrations of 0.05, 0.15, 0.25 and 0.4 g L⁻¹. Biometric variables, yield of bulbs and biochemical variables were evaluated indicating that the use of A. quadricellulare promoted plant growth and increases in bulb caliber and yield of both onion cultivars. The microalga biomass stimulated plant metabolism by increases in contents of chlorophyll, carotenoids, amino acids, and the nitrate reductase enzyme activity in leaves, also free amino acids and total sugar contents in bulbs, highlighting the biomass concentration of 0.25 g L⁻¹. Full article

(This article belongs to the Section Plant Nutrition)

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14 pages, 1818 KiB

Open AccessEditor’s ChoiceArticle

Optimization of the Yield, Total Phenolic Content, and Antioxidant Capacity of Basil by Controlling the Electrical Conductivity of the Nutrient Solution

by Xiaowei Ren, Na Lu, Wenshuo Xu, Yunfei Zhuang and Michiko Takagaki

Horticulturae 2022, 8(3), 216; https://doi.org/10.3390/horticulturae8030216 - 1 Mar 2022

Cited by 10 | Viewed by 2996

Abstract

Hydroponic cultivation using nutrient solution (NS) is the main cultivation method employed by plant factories with artificial lighting (PFALs). The electrical conductivity (EC) of NSs influences the yield and quality of vegetables. The purpose of this study was to optimize the yield and [...] Read more.

Hydroponic cultivation using nutrient solution (NS) is the main cultivation method employed by plant factories with artificial lighting (PFALs). The electrical conductivity (EC) of NSs influences the yield and quality of vegetables. The purpose of this study was to optimize the yield and antioxidant accumulation of basil in a PFAL by EC management. In experiment 1, basil plants were grown under four different ECs (0.5, 1.0, 3.0, and 5.0 dS m⁻¹) after transplanting. At 18 days after treatment, the highest levels of shoot fresh and dry weights, leaf fresh and dry weights, and leaf area were observed at an EC of 3.0 dS m⁻¹. However, low-EC treatments (0.5 and 1.0 dS m⁻¹) generated total phenolic content (TPC) and antioxidant capacities that were higher than those of other EC treatments (3.0 and 5.0 dS m⁻¹). In experiment 2, basil plants were grown at an EC of 3.0 dS m⁻¹ for 13 or 15 days, then treated with water or NS with low ECs (0.5 and 1.0 dS m⁻¹) for 5 or 3 days before harvest. The short-term low-EC treatments, especially, water for 3 days and 0.5 dS m⁻¹ for 5 days, significantly increased the TPC and antioxidant capacity of leaves without significantly decreasing the yields of basil, compared with the control. In conclusion, yield of basil was optimized with an EC of 3.0 dS m⁻¹; however, the TPC and antioxidant capacity of basil were significantly increased by low ECs of 0.5 and 1.0 dS m⁻¹. Short-term low-EC treatments (0.5 dS m⁻¹ for 5 days or water for 3 days) could be used to promote the TPC and antioxidant capacity in leaves without sacrificing yield of basil significantly. Full article

(This article belongs to the Special Issue Urban Horticulture - New Trends and Technologies)

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20 pages, 7329 KiB

Open AccessEditor’s ChoiceArticle

The Inclusion of Green Light in a Red and Blue Light Background Impact the Growth and Functional Quality of Vegetable and Flower Microgreen Species

by Matteo Orlando, Alice Trivellini, Luca Incrocci, Antonio Ferrante and Anna Mensuali

Horticulturae 2022, 8(3), 217; https://doi.org/10.3390/horticulturae8030217 - 1 Mar 2022

Cited by 18 | Viewed by 5986

Abstract

Microgreens are edible seedlings of vegetables and flowers species which are currently considered among the five most profitable crops globally. Light-emitting diodes (LEDs) have shown great potential for plant growth, development, and synthesis of health-promoting phytochemicals with a more flexible and feasible spectral [...] Read more.

Microgreens are edible seedlings of vegetables and flowers species which are currently considered among the five most profitable crops globally. Light-emitting diodes (LEDs) have shown great potential for plant growth, development, and synthesis of health-promoting phytochemicals with a more flexible and feasible spectral manipulation for microgreen production in indoor farms. However, research on LED lighting spectral manipulation specific to microgreen production, has shown high variability in how these edible seedlings behave regarding their light environmental conditions. Hence, developing species-specific LED light recipes for enhancement of growth and valuable functional compounds is fundamental to improve their production system. In this study, various irradiance levels and wavelengths of light spectrum produced by LEDs were investigated for their effect on growth, yield, and nutritional quality in four vegetables (chicory, green mizuna, china rose radish, and alfalfa) and two flowers (french marigold and celosia) of microgreens species. Microgreens were grown in a controlled environment using sole-source light with different photosynthetic photon flux density (110, 220, 340 µmol m⁻² s⁻¹) and two different spectra (RB: 65% red, 35% blue; RGB: 47% red, 19% green, 34% blue). At harvest, the lowest level of photosynthetically active photon flux (110 µmol m⁻² s⁻¹) reduced growth and decreased the phenolic contents in almost all species. The inclusion of green wavelengths under the highest intensity showed positive effects on phenolic accumulation. Total carotenoid content and antioxidant capacity were in general enhanced by the middle intensity, regardless of spectral combination. Thus, this study indicates that the inclusion of green light at an irradiance level of 340 µmol m⁻² s⁻¹ in the RB light environment promotes the growth (dry weight biomass) and the accumulation of bioactive phytochemicals in the majority of the microgreen species tested. Full article

(This article belongs to the Special Issue Indoor Farming and Artificial Cultivation)

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26 pages, 2798 KiB

Open AccessEditor’s ChoiceReview

Top Ten Most Important U.S.-Regulated and Emerging Plant-Parasitic Nematodes

by Mihail Kantor, Zafar Handoo, Camelia Kantor and Lynn Carta

Horticulturae 2022, 8(3), 208; https://doi.org/10.3390/horticulturae8030208 - 26 Feb 2022

Cited by 21 | Viewed by 6437

Abstract

Plant-parasitic nematodes (PPNs) are important pests that cause an estimated ten billion dollars of crop loss each year in the United States and over 100 billion dollars globally. The Animal and Plant Health Inspection Service (APHIS) within the U.S. Department of Agriculture maintains [...] Read more.

Plant-parasitic nematodes (PPNs) are important pests that cause an estimated ten billion dollars of crop loss each year in the United States and over 100 billion dollars globally. The Animal and Plant Health Inspection Service (APHIS) within the U.S. Department of Agriculture maintains and updates the U.S. Regulated Plant Pest list. Currently, the number of PPNs regulated by APHIS includes more than 60 different species. This review focuses on the top ten most economically important regulated and emerging plant-parasitic nematodes and summarizes the diagnostics of morphological and some molecular features for distinguishing them. These ten major previously described nematode species are associated with various economically important crops from around the world. This review also includes their current distribution in the U.S. and a brief historical background and updated systematic position of these species. The species included in this review include three PPNs considered by the U.S. Department of Agriculture as invasive invertebrates Globodera pallida, Globodera rostochiensis, and Heterodera glycines; four regulated PPNs, namely Bursaphelenchus xylophilus, Meloidogyne fallax, Ditylenchus dipsaci, and Pratylenchus fallax; and the three emerging PPNs Meloidogyne chitwoodi, Meloidogyne enterolobii, and Litylenchus crenatae mccannii. Full article

(This article belongs to the Special Issue Recent Advance in the Identification and Diagnostics of Plant-Parasitic Nematodes)

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10 pages, 2200 KiB

Open AccessEditor’s ChoiceArticle

Shoot Development through Modified Transverse Thin Cell Layer (tTCL) Culture of Phalaenopsis Hybrid Protocorms

by Kuo-Chin Lo, Jualang Azlan Gansau, Chia-Hung Shih and Chien-Yuan Kao

Horticulturae 2022, 8(3), 206; https://doi.org/10.3390/horticulturae8030206 - 26 Feb 2022

Cited by 4 | Viewed by 2566

Abstract

This first-attempt study used microtome-based methods to generate a thin cell layer culture for the micropropagation of Phal. Hwafeng Redjewel × Phal. New Cinderella. Protocorms were embedded in various agarose concentrations (8–12%, w/v) and dried from 1 to 8 h [...] Read more.

This first-attempt study used microtome-based methods to generate a thin cell layer culture for the micropropagation of Phal. Hwafeng Redjewel × Phal. New Cinderella. Protocorms were embedded in various agarose concentrations (8–12%, w/v) and dried from 1 to 8 h before sectioning with a microtome. Optimal conditions for slicing sections of 100 to 300 μm were achieved when the protocorms were embedded at 10% (w/v) agarose and dried for 4 h under laminar flow, and the hardness of the agarose block under these conditions reached 641.8 ± 9.5 g·cm⁻². The sectioned protocorms that were cultured on an MS medium supplemented with 1.2 mg·L⁻¹ 6-benzylaminopurine and 0.1 mg·L⁻¹ α-naphthaleneacetic acid were capable of growth and differentiated through the neoformation of protocorm-like bodies (PLBs) and/or callus before subsequent regeneration into plantlets and development into healthy plants in a nursery environment. The results of this study demonstrate that microtome-based tTCL is a reliable and promising approach for mass propagation and possible virus-free propagation objectives for Phalaenopsis. Full article

(This article belongs to the Special Issue Advances in Orchid Physiology, Micropropagation, Breeding and Genomics)

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13 pages, 1818 KiB

Open AccessEditor’s ChoiceArticle

Effect of Chitosan-Poly(Acrylic Acid) Complexes and Two Nutrient Solutions on the Growth and Yield of Two Habanero Pepper Cultivars

by Rogelio Enrique Palacios-Torres, Amadeo Santos-Chavez, Hortensia Ortega-Ortiz, Ana Rosa Ramírez-Seañez, José Antonio Yam-Tzec, Adolfo Amador-Mendoza, Antonio Juárez-Maldonado, Maribel Reyes-Osornio and Hipólito Hernández-Hernández

Horticulturae 2022, 8(3), 201; https://doi.org/10.3390/horticulturae8030201 - 24 Feb 2022

Cited by 4 | Viewed by 2141

Abstract

Chitosan (CS) is a natural polymer used in agriculture as a biostimulant that has been evaluated in different plant models. In this study, we evaluated the effect of the foliar application of chitosan–poly(acrylic acid) complexes (CS–PAA) and two nutrient solutions (A and B) [...] Read more.

Chitosan (CS) is a natural polymer used in agriculture as a biostimulant that has been evaluated in different plant models. In this study, we evaluated the effect of the foliar application of chitosan–poly(acrylic acid) complexes (CS–PAA) and two nutrient solutions (A and B) on the parameters of growth and yield of two habanero pepper cultivars (Chichen Itza and Jaguar) in a greenhouse. Over the course of the experiment, eight foliar applications were carried out at 15-day intervals. Our results showed that foliar applications of CS–PAA complexes have a biostimulant effect on the habanero pepper crop by increasing the total dry biomass of the plant and the number of fruits of the two cultivars. Regarding nutrient solutions, the nutrient solution A increased the yield of the Chichen Itza cultivar; this effect was because it had a better balance of potassium and calcium compared to the nutrient solution B. These results provide advances on the use of CS–PAA complexes as a biostimulant and the management of nutrient solutions in the crop of habanero peppers. Full article

(This article belongs to the Special Issue Hydroponics in Vegetable Production)

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17 pages, 4356 KiB

Open AccessEditor’s ChoiceArticle

Research on Mixing Law of Liquid Fertilizer Injected into Irrigation Pipe

by Zhiyang Zhang, Chao Chen, Hong Li and Pan Tang

Horticulturae 2022, 8(3), 200; https://doi.org/10.3390/horticulturae8030200 - 24 Feb 2022

Cited by 6 | Viewed by 2306

Abstract

The time and position that fertilizer takes to uniformly mix with water in an irrigation system significantly affects the development of a fertilization strategy. A pipe irrigation system was used to study the fertilizer–water mixing law in irrigation pipes using numerical simulation and [...] Read more.

The time and position that fertilizer takes to uniformly mix with water in an irrigation system significantly affects the development of a fertilization strategy. A pipe irrigation system was used to study the fertilizer–water mixing law in irrigation pipes using numerical simulation and experiments. The effect of the diameter of the water pipe and fertilizer pipe, water and fertilizer flow rates, concentration and viscosity of fertilizer, frequency of fertilizer injection on the mixing speed, and uniform mixing length indicated that the frequency of fertilizer injection did not affect the mixing process. The increase in the water pipe diameter and fertilizer flow rate or the decrease in fertilizer pipe and water flow rate diameter result in the increase of the speed of fertilizer solution mixing with water along the radial direction of the mixing pipe. The uniform mixing length was directly proportional to the fertilizer pipe diameter, water pipe diameter, water flow rate, and fertilizer viscosity, while it was inversely proportional to the flow rate and concentration of fertilizer. The relationship between the uniform mixing length and six influencing factors was fitted, the fitting was highly accurate, and the fitting equation can be used to predict the uniform mixing length under other conditions. Full article

(This article belongs to the Special Issue Advanced of Horticulture Innovative Irrigation Technologies)

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13 pages, 2370 KiB

Open AccessEditor’s ChoiceArticle

Nutrient Uptake and Yield of Chinese Cabbage (Brassica rapa L. Chinensis) Increased with Application of Macadamia Husk Compost

by Dembe Maselesele, John B. O. Ogola and Romeo N. Murovhi

Horticulturae 2022, 8(3), 196; https://doi.org/10.3390/horticulturae8030196 - 23 Feb 2022

Cited by 5 | Viewed by 4594

Abstract

There is a dearth of information on the effect of macadamia husk compost (MHC) on the productivity of short-season, shallow-rooted annual crops. We assessed the response of yield and nutrient uptake of Chinese cabbage (Brassica rapa L. Chinensis) to MHC application. [...] Read more.

There is a dearth of information on the effect of macadamia husk compost (MHC) on the productivity of short-season, shallow-rooted annual crops. We assessed the response of yield and nutrient uptake of Chinese cabbage (Brassica rapa L. Chinensis) to MHC application. The treatments (zero control, inorganic fertilizer (100:60:60 kg NPK ha⁻¹), and 15 and 30 t ha⁻¹ MHC) were arranged in a randomized complete block design and replicated three times. Number of leaves, leaf area index, leaf biomass, and leaf nutrient concentration (N, P, K, Ca, Mg, Zn, Cu, Mn, and B) were determined at 28, 46, and 74 days after transplanting (DAT), and root length and root biomass were determined at 74 DAT. Inorganic fertilizer and MHC increased root biomass and root length with greater increases recorded at the higher MHC rates. Number of leaves, leaf area index, leaf biomass, and nutrient concentration were greater with application of inorganic fertilizer (28 DAT) and 30 t ha⁻¹ (74 DAT) suggesting that the effect of organic soil amendments is more pronounced over the long run compared with inorganic fertilizers. The concentration of macronutrients in the leaf increased with application of MHC and inorganic fertilizer. Clearly, MHC may be beneficial in improving the leaf yield and nutrient uptake of Chinese cabbage in a loamy sand soil, but the effect varies with time of harvesting. Full article

(This article belongs to the Special Issue Recent Advances in Nutrition and Fertilization of Horticultural Crops)

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17 pages, 3489 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Grapevine Response to Stress Generated by Excessive Temperatures during the Budburst

by Sergio Tombesi, Paolo Sabbatini, Tommaso Frioni, Francesca Grisafi, Federico Barone, Paolo Zani, Alberto Palliotti and Stefano Poni

Horticulturae 2022, 8(3), 187; https://doi.org/10.3390/horticulturae8030187 - 22 Feb 2022

Cited by 3 | Viewed by 2351

Abstract

At springtime, the formation of stem somatic traits (stem elongation and leaf growth) and reproductive activity (flowering and fruit set) occur simultaneously. They are all competing carbon sinks, with an extremely high demand for carbohydrates. The shoot growth rate is strongly related to [...] Read more.

At springtime, the formation of stem somatic traits (stem elongation and leaf growth) and reproductive activity (flowering and fruit set) occur simultaneously. They are all competing carbon sinks, with an extremely high demand for carbohydrates. The shoot growth rate is strongly related to environmental temperature, which, according to climate change scenarios, is expected to increase also in extremes. Our hypothesis was that the increase in temperature during budburst could increase the vegetative carbon sink strength reducing the carbon stock available for the reproductive activity jeopardizing flowering of the next year. In our experiment, we artificially conditioned grapevine budburst by exposing the growing shoots to different temperature regimes. Higher temperatures during the spring vegetative growth favored shoot stem extension at the detriment of shoot leaf area. This caused a reduction in vine CO₂ assimilation, which, combined with the competition of the growing vegetative organs, affected the concurrent reproductive activity, with carry-over effects on the following year, resulting in a limited flower initiation in dormant buds. These results suggest that the increase in springtime temperature can alter canopy development and vine physiology, resulting in the reduction in reproductive activity with an economical negative impact on grapevine productivity. Full article

(This article belongs to the Section Viticulture)

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13 pages, 922 KiB

Open AccessEditor’s ChoiceArticle

Graded Moisture Deficit Effect on Secondary Metabolites, Antioxidant, and Inhibitory Enzyme Activities in Leaf Extracts of Rosa damascena Mill. var. trigentipetala

by Kamel Hessini, Hanen Wasli, Hatim M. Al-Yasi, Esmat F. Ali, Ahmed A. Issa, Fahmy A. S. Hassan and Kadambot H. M. Siddique

Horticulturae 2022, 8(2), 177; https://doi.org/10.3390/horticulturae8020177 - 21 Feb 2022

Cited by 23 | Viewed by 2384

Abstract

Drought affects plant growth and yield in many agricultural areas worldwide by producing negative water potentials in the root zone that reduce water availability, affecting plant development and metabolism. This study investigated the effect of varying moisture regimes (100% field capacity (FC), well-watered [...] Read more.

Drought affects plant growth and yield in many agricultural areas worldwide by producing negative water potentials in the root zone that reduce water availability, affecting plant development and metabolism. This study investigated the effect of varying moisture regimes (100% field capacity (FC), well-watered plants, 50% FC (moderate water stress), and 25% FC (severe water stress)) on growth parameters, chlorophyll content, and bioactive molecule patterns, and the impact on antioxidant, lipoxygenase (LOX), and acetylcholinesterase (AChE) activities in Rosa damascena. The water deficit treatments reduced biomass production for both treatments (−29 and −33%, respectively, for MWS and SWS) and total chlorophyll (−18 and −38% respectively for MWS and SWS), relative to the control. The 50% FC treatment had the greatest effect on the phenolic profiles and their respective functionalities, with significant increases in the levels of total phenolic, benzoic (gallic, p-coumaric, and syringic acids) (+32%), and cinnamic (caffeic and trans-cinnamic acid) acids (+19%) and flavonoids (epicatechin-3-O-gallate) (+15%) compared to well-watered leaves (control leaves). The 50% FC treatment also exhibited the highest potential antioxidant activities (apart from NO-quenching activity), evidenced by the lowest IC₅₀ and EC₅₀ values. The inhibitory LOX and AChE capacities varied depending on the severity of stress, with superior activity in the 50% FC treatment. Overall, the drought tolerance in rose was associated mainly with its suitable manipulation of antioxidant production and orderly regulation of LOX and AChE activities. Full article

(This article belongs to the Special Issue Drought Stress in Horticultural Plants)

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11 pages, 9741 KiB

Open AccessEditor’s ChoiceArticle

Effects of Light Intensity and Temperature on the Photosynthesis Characteristics and Yield of Lettuce

by Jing Zhou, Pingping Li and Jizhang Wang

Horticulturae 2022, 8(2), 178; https://doi.org/10.3390/horticulturae8020178 - 21 Feb 2022

Cited by 29 | Viewed by 11579

Abstract

Lettuce is an important vegetable in horticulture, but information about the interactive effects of light and temperature on its photosynthetic characteristics was inadequate. This work investigated the effects of three temperatures (15/10 (T15), 23/18 (T23), and 30/23 °C (T30)) and five light treatments [...] Read more.

Lettuce is an important vegetable in horticulture, but information about the interactive effects of light and temperature on its photosynthetic characteristics was inadequate. This work investigated the effects of three temperatures (15/10 (T15), 23/18 (T23), and 30/23 °C (T30)) and five light treatments (100 (P100), 200 (P200), 350 (P350), 500 (P500), and 600 μmol·m⁻²·s⁻¹ (P600)) on the light–response curves, chlorophyll content, and yield of lettuce. The results showed that the maximum photosynthetic rate, light saturation point, chlorophyll content, and yield of lettuce were all the highest at T23 compared with T15 and T30 under different light intensities. Under the same temperature conditions, the photosynthesis capacity and yield of lettuce in the P350 and P500 treatments at T15, P350, P500, and P600 treatments at T23 and P500, and P600 treatments at T30 were larger than other light treatments. The results suggested that temperature play had a more pronounced influence on photosynthesis and yield in lettuce, but the appropriate levels of light intensity improved its potential photosynthetic capacity and yield under different temperature conditions. Full article

(This article belongs to the Section Developmental Physiology, Biochemistry, and Molecular Biology)

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20 pages, 3619 KiB

Open AccessEditor’s ChoiceArticle

Response of Tomato-Pseudomonas Pathosystem to Mild Heat Stress

by Loredana Scalschi, Emma Fernández-Crespo, Marcel Pitarch-Marin, Eugenio Llorens, Ana Isabel González-Hernández, Gemma Camañes, Begonya Vicedo and Pilar García-Agustín

Horticulturae 2022, 8(2), 174; https://doi.org/10.3390/horticulturae8020174 - 20 Feb 2022

Cited by 2 | Viewed by 2018

Abstract

Higher plants suffer from mild heat stress when temperatures increase by 5 °C above optimum growth temperatures. This produces changes at the cellular and metabolic levels, allowing plants to adapt to heat conditions. This study investigated an increase of 5 °C above the [...] Read more.

Higher plants suffer from mild heat stress when temperatures increase by 5 °C above optimum growth temperatures. This produces changes at the cellular and metabolic levels, allowing plants to adapt to heat conditions. This study investigated an increase of 5 °C above the optimum growth temperature (26 °C) of tomato plants in the tomato—Pseudomonas syringae pv. tomato pathosystem. A temperature increase above 26 °C affects plant development, the defensive pathways activated against Pseudomonas syringae pv. tomato strain DC3000 (PstDC3000), and the bacterial growth and virulence machinery. The results demonstrated that tomato plants were able to acclimate to mild heat stress, showing no symptoms of damage. Moreover, plants subjected to a 5 °C increase (T31 °C plants) showed higher basal levels of metabolites such as proline and putrescine, which probably act as compatible osmolytes. This demonstrates their importance as key components of thermotolerance. When grown under mild heat stress, plants were less susceptible to PstDC3000 and showed increased accumulation of abscisic acid, jasmonic acid-isoleucine, and spermine. In addition, the temperature increase negatively affected the infectivity of PstDC3000. Inhibition of the genes responsible for quorum sensing establishment and synthesis of flagellin and coronatine was observed in bacteria extracted from T31 °C plants. Analysis of the genes involved in the synthesis of the type III secretion system indicates the important role of this system in bacterial growth under these conditions. As the known resistance mechanisms involved in the defense against PstDC3000 were not activated, the changes in its virulence mechanisms under high temperatures may explain the lower infection observed in the T31 °C plants. Full article

(This article belongs to the Special Issue Host-Pathogen Interaction in Climate Change Scenario)

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20 pages, 2290 KiB

Open AccessEditor’s ChoiceReview

Molecular and Metabolic Changes under Environmental Stresses: The Biosynthesis of Quality Components in Preharvest Tea Shoots

by Jianjun Liu, Beibei Wen, Xiaobo Liu, Yun Yang, Meifeng Li and Xiaojing Wang

Horticulturae 2022, 8(2), 173; https://doi.org/10.3390/horticulturae8020173 - 19 Feb 2022

Cited by 3 | Viewed by 2447

Abstract

Severe environments impose various abiotic stresses on tea plants. Although much is known about the physiological and biochemical responses of tea (Camellia sinensis L.) shoots under environmental stresses, little is known about how these stresses impact the biosynthesis of quality components. This [...] Read more.

Severe environments impose various abiotic stresses on tea plants. Although much is known about the physiological and biochemical responses of tea (Camellia sinensis L.) shoots under environmental stresses, little is known about how these stresses impact the biosynthesis of quality components. This review summarizes and analyzes the changes in molecular and quality components in tea shoots subjected to major environmental stresses during the past 20 years, including light (shade, blue light, green light, and UV-B), drought, high/low temperature, CO₂, and salinity. These studies reveal that carbon and nitrogen metabolism is critical to the downstream biosynthesis of quality components. Based on the molecular responses of tea plants to stresses, a series of artificial methods have been suggested to treat the pre-harvest tea plants that are exposed to inhospitable environments to improve the quality components in shoots. Furthermore, many pleiotropic genes that are up- or down-regulated under both single and concurrent stresses were analyzed as the most effective genes for regulating multi-resistance and quality components. These findings deepen our understanding of how environmental stresses affect the quality components of tea, providing novel insights into strategies for balancing plant resistance, growth, and quality components in field-based cultivation and for breeding plants using pleiotropic genes. Full article

(This article belongs to the Collection The Correlation of Stress Response and Organ Development in Horticultural Crops)

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10 pages, 906 KiB

Open AccessEditor’s ChoiceArticle

Identification of Suitable Reference Genes for qRT-PCR Normalization in Kiwifruit

by Yuanjie Zhou, Hui Xia, Xinling Liu, Zhiyi Lin, Yuqi Guo, Honghong Deng, Jin Wang, Lijin Lin, Qunxian Deng, Xiulan Lv, Kunfu Xu and Dong Liang

Horticulturae 2022, 8(2), 170; https://doi.org/10.3390/horticulturae8020170 - 18 Feb 2022

Cited by 7 | Viewed by 2140

Abstract

Reference genes are used for the correction of qRT-PCR data, and it is necessary to investigate the optimum reference gene under certain conditions. The expression levels of seven traditional reference genes ACT1, ACT2, GAPDH, 18S rRNA, UBQ, TUB [...] Read more.

Reference genes are used for the correction of qRT-PCR data, and it is necessary to investigate the optimum reference gene under certain conditions. The expression levels of seven traditional reference genes ACT1, ACT2, GAPDH, 18S rRNA, UBQ, TUB and CYP were analyzed using qRT-PCR in different varieties, tissues, developmental stages and hormone (or pollen polysaccharide) treatments in kiwifruit. Gene expression stability was assessed with the help of three common software (geNorm, NormFinder, BestKeeper), and the minimum number of reference genes necessary for normalization was also determined. GAPDH, ACT1 and ACT2 were selected as reference genes for different genotypes of kiwifruit. GAPDH and UBQ were the best combinations of reference genes for root, stem, leaf, flower and fruit. GAPDH and ACT1 could be the preferred reference genes for normalization of qRT-PCR data during fruit development. The pairing of ACT1 and UBQ constituted the optimal combination of reference genes in kiwifruit treated with different hormones (or pollen polysaccharide). This study provides a new and reliable option for the use of reference genes in the analysis of gene expression patterns of interest in kiwifruit. Full article

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16 pages, 3944 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Metabolic Profiling of Organic Acids Reveals the Involvement of HuIPMS2 in Citramalic Acid Synthesis in Pitaya

by Jiaxuan Chen, Yuanju Yuan, Fangfang Xie, Zhike Zhang, Jianye Chen, Rong Zhang, Jietang Zhao, Guibing Hu and Yonghua Qin

Horticulturae 2022, 8(2), 167; https://doi.org/10.3390/horticulturae8020167 - 16 Feb 2022

Cited by 3 | Viewed by 2297

Abstract

Pitayas are rich in organic acids, especially citramalic acid, which is significantly higher than the plants. However, the mechanism of citramalic acid biosynthesis remains to be fully elucidated. In this study, organic acid compositions and contents, as well as expression patterns of key [...] Read more.

Pitayas are rich in organic acids, especially citramalic acid, which is significantly higher than the plants. However, the mechanism of citramalic acid biosynthesis remains to be fully elucidated. In this study, organic acid compositions and contents, as well as expression patterns of key genes related to organic acid metabolism were analyzed during fruit maturation of four different pitaya cultivars i.e., ‘Guanhuabai’ (GHB), ‘Guanhuahong’ (GHH), ‘Wucihuanglong’ (WCHL), and ‘Youcihuanglong’ (YCHL). The total organic acid contents increased first and then declined during fruit maturation. The main organic acids were citramalic acid during the early stages of GHB, GHH, and WCHL pitayas, and dominated by malic acid as fruit maturation. In comparison, citric acid and malic acid were main organic acid for ‘YCHL’ pitaya. Citramalate synthase (IPMS) was involved in the synthesis of citramalic acid, and three types of HuIPMS i.e., HuIPMS1, HuIPMS2, and HuIPMS3, were obtained in our study. Highest expression levels of HuIPMS1 were detected in sepals, while HuIPMS2 and HuIPMS3 exhibited preferential expression in tender stems and ovaries. The expression levels of HuIPMS2 and HuIPMS3 were positively correlated with the content of citramalic acid in the four pitaya cultivars. HuIPMS2 was a chloroplast-localized protein, while HuIPMS3 presented a cytoplasmic-like and nuclear subcellular localization. These findings provide an important basis for further understanding of the molecular mechanism that leads to citramalic acid metabolism during pitaya fruit maturation. Full article

(This article belongs to the Collection Advances in Fruit Quality Formation and Regulation)

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20 pages, 9210 KiB

Open AccessEditor’s ChoiceReview

Volatile Organic Compounds from Basil Essential Oils: Plant Taxonomy, Biological Activities, and Their Applications in Tropical Fruit Productions

by Tibet Tangpao, Nutthawut Charoimek, Patipon Teerakitchotikan, Noppol Leksawasdi, Kittisak Jantanasakulwong, Pornchai Rachtanapun, Phisit Seesuriyachan, Yuthana Phimolsiripol, Thanongsak Chaiyaso, Warintorn Ruksiriwanich, Pensak Jantrawut, Hien Van Doan, Ratchadawan Cheewangkoon and Sarana Rose Sommano

Horticulturae 2022, 8(2), 144; https://doi.org/10.3390/horticulturae8020144 - 8 Feb 2022

Cited by 19 | Viewed by 8963

Abstract

Basils of the genus Ocimum are aromatic plants grown widely throughout the tropical and temperate regions. The essential oils obtained from their aerial parts are enriched with volatile organic compounds with high market demand for food and pharmaceutical industries. The volatile organic compounds [...] Read more.

Basils of the genus Ocimum are aromatic plants grown widely throughout the tropical and temperate regions. The essential oils obtained from their aerial parts are enriched with volatile organic compounds with high market demand for food and pharmaceutical industries. The volatile organic compounds have been shown to exhibit biological activities. Therefore, their novel applications have been extensively explored in the last few decades. The most widely available basils in the tropical areas include white holy basil (O. sanctum var. Shyama), red holy basil (O. sanctum var. Rama), Thai basil (O. basilicum var. thyrsiflorum), lemon basil (O. citriodorum), and tree basil (O. gratissimum). Over 60 volatiles of different classes have been exclusively described, and some of them could be useful as biomarkers for genotype specification. The major volatile ingredient is the phenylpropanoids, such as methyl eugenol, which has the potential as a natural product for mitigating Oriental fruit fly (Bactrocera dorsalis) during tropical fruit production. Moreover, basil essential oils are also used to control diseases of the fruits during post-harvest storage. As a result, the application of basil essential oils as a sustainable defect control strategy for tropical fruit value chains seems intriguing. This review provides comprehensive information on plant taxonomy and volatile compositions of the essential oil fractions from different basil species. Their biological activities and applications are also discussed, mainly during the pre- and post-production of tropical fruits. Additionally, the available techniques to enhance the efficacy of the volatile active compounds are also described. Full article

(This article belongs to the Special Issue Phytochemicals of Natural Products: Analysis and Biological Activities)

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9 pages, 2355 KiB

Open AccessEditor’s ChoiceArticle

Effects of Magnesium Application on Tipburn Incidence and Calcium Acquisition in Lisianthus (Eustoma grandiflorum) Cultivars

by Takanori Kuronuma, Kanami Ishikawa and Hitoshi Watanabe

Horticulturae 2022, 8(2), 132; https://doi.org/10.3390/horticulturae8020132 - 31 Jan 2022

Cited by 1 | Viewed by 2578

Abstract

The occurrence of tipburn is a severe problem in horticulture crop production. A previous study suggested that, in lisianthus, tipburn is caused by imbalanced calcium (Ca) distribution. However, there are few studies on the effects of other cations on tipburn incidence in lisianthus [...] Read more.

The occurrence of tipburn is a severe problem in horticulture crop production. A previous study suggested that, in lisianthus, tipburn is caused by imbalanced calcium (Ca) distribution. However, there are few studies on the effects of other cations on tipburn incidence in lisianthus cultivars. In this study, to determine the effect of Magnesium (Mg) concentration in nutrient solution on tipburn incidence and Ca and Mg acquisition, three lisianthus cultivars (‘Celeb Wine’: CW, ‘Reina White’: RW, and ‘Voyage Peach’: VP) were cultivated under different Mg concentrations in nutrient solution (12 ppm, 34.7 ppm, and 75.4 ppm). Under high nutritional Mg concentrations, CW and RW had significantly decreased tipburn severity, while VP showed no significant differences in tipburn severity among the treatments. Total Ca concentrations in all cultivars significantly increased at higher nutritional Mg concentrations, which indicated that Mg application in lisianthus cultivars promoted Ca acquisition. Furthermore, it was suggested that CW and RW had the ability to distribute increased Mg to the tip of the upper leaves, thereby promoting Ca distribution. Thus, a decrease in tipburn severity in CW and RW at higher nutritional Mg concentrations appeared to occur. Full article

(This article belongs to the Section Plant Nutrition)

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28 pages, 10559 KiB

Open AccessEditor’s ChoiceArticle

Adaptalight: An Inexpensive PAR Sensor System for Daylight Harvesting in a Micro Indoor Smart Hydroponic System

by Joseph D Stevens, David Murray, Dean Diepeveen and Danny Toohey

Horticulturae 2022, 8(2), 105; https://doi.org/10.3390/horticulturae8020105 - 25 Jan 2022

Cited by 8 | Viewed by 3948

Abstract

Environmental changes and the reduction in arable land have led to food security concerns around the world, particularly in urban settings. Hydroponic soilless growing methods deliver plant nutrients using water, conserving resources and can be constructed nearly anywhere. Hydroponic systems have several complex [...] Read more.

Environmental changes and the reduction in arable land have led to food security concerns around the world, particularly in urban settings. Hydroponic soilless growing methods deliver plant nutrients using water, conserving resources and can be constructed nearly anywhere. Hydroponic systems have several complex attributes that need to be managed, and this can be daunting for the layperson. Micro Indoor Smart Hydroponics (MISH) leverage Internet of Things (IoT) technology to manage the complexities of hydroponic techniques, for growing food at home for everyday citizens. Two prohibitive costs in the advancement of MISH systems are power consumption and equipment expense. Reducing cost through harvesting ambient light can potentially reduce power consumption but must be done accurately to sustain sufficient plant yields. Photosynthetic Active Radiation (PAR) meters are commercially used to measure only the light spectrum that plants use, but are expensive. This study presents Adaptalight, a MISH system that harvests ambient light using an inexpensive AS7265x IoT sensor to measure PAR. The system is built on commonly found IoT technology and a well-established architecture for MISH systems. Adpatalight was deployed in a real-world application in the living space of an apartment and experiments were carried out accordingly. A two-phase experiment was conducted over three months, each phase lasting 21 days. Phase one measured the IoT sensor’s capability to accurately measure PAR. Phase two measured the ability of the system to harvest ambient PAR light and produce sufficient yields, using the calibrated IoT sensor from phase one. The results showed that the Adaptalight system was successful in saving a significant amount of power, harvesting ambient PAR light and producing yields with no significant differences from the control. The amount of power savings would be potentially greater in a location with more ambient light. Additionally, the findings show that, when calibrated, the AS7265x sensor is well suited to accurately measure PAR light in MISH systems. Full article

(This article belongs to the Special Issue Transformation toward Sustainability in Controlled Environment Agriculture)

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16 pages, 1818 KiB

Open AccessEditor’s ChoiceArticle

Can Light Spectrum Composition Increase Growth and Nutritional Quality of Linum usitatissimum L. Sprouts and Microgreens?

by Martina Puccinelli, Rita Maggini, Luciana G. Angelini, Marco Santin, Marco Landi, Silvia Tavarini, Antonella Castagna and Luca Incrocci

Horticulturae 2022, 8(2), 98; https://doi.org/10.3390/horticulturae8020098 - 22 Jan 2022

Cited by 13 | Viewed by 4133

Abstract

Flaxseed could be suitable for obtaining high-quality sprouts and microgreens thanks to high amounts of nutrients and antioxidant, antidiabetic, and anticancer compound content in its seeds. Recent studies highlighted that seedling growth, nutritional compound, and secondary metabolite content can be strongly managed by [...] Read more.

Flaxseed could be suitable for obtaining high-quality sprouts and microgreens thanks to high amounts of nutrients and antioxidant, antidiabetic, and anticancer compound content in its seeds. Recent studies highlighted that seedling growth, nutritional compound, and secondary metabolite content can be strongly managed by regulation of the light spectrum used during germination. The present study intended to shed light on flaxseed as emerging and novel species for sprouts and microgreens and to evaluate the effect of light, with different spectrum compositions (100% blue, 100% red, 100% green, and red:green:blue—1:1:1) on the performance of flax microgreens and sprouts grown indoors under controlled conditions. Microgreens showed, compared to sprouts, a higher chlorophyll (+62.6%), carotenoid (+24.4%), and phenol content (+37.8%), antioxidant capacity (+25.1%) and a lower dry matter content (−30.7%). Besides, microgreens treated with 100% blue light were characterized by the highest content of flavonoids (2.48 mg CAE g⁻¹ FW), total phenols (3.76 mg GAE g⁻¹ FW), chlorogenic acid (1.10 mg g⁻¹ FW), and antioxidant capacity (8.06 µmol TEAC g⁻¹ FW). The paper demonstrates the feasibility of obtaining flax sprouts and microgreens indoors with a considerable antioxidant capacity and health-promoting compounds by modulating the light spectrum. Full article

(This article belongs to the Special Issue Indoor Farming and Artificial Cultivation)

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13 pages, 2736 KiB

Open AccessEditor’s ChoiceArticle

The Effect of the Double Reasoned Maturation (DMR) Method on the Chemical Composition of the Juice and Wine of the Bianca Grape Cultivar

by Diána Ágnes Nyitrainé Sárdy, Erzsébet Krisztina Németh, Réka Matolcsi, Anna Szabó and Zsuzsanna Varga

Horticulturae 2022, 8(2), 97; https://doi.org/10.3390/horticulturae8020097 - 21 Jan 2022

Cited by 1 | Viewed by 2542

Abstract

This paper aims to detect the effects of DMR (double reasoned maturation) method, and if it is able to increase the quality of Hungary’s most distributed white wine variety, Bianca. The resistant interspecific hybrid Bianca cultivar can accumulate high sugar content during ripening, [...] Read more.

This paper aims to detect the effects of DMR (double reasoned maturation) method, and if it is able to increase the quality of Hungary’s most distributed white wine variety, Bianca. The resistant interspecific hybrid Bianca cultivar can accumulate high sugar content during ripening, but it is prone to drastic acid loss, which can lead to deficient microbiological stability of wines. The DMR method is suitable for achieving fruit with better sugar/acid ratio due to the shrinking of the berries. The DMR treatment was found to be a possible tool for avoiding rapid acid loss in Bianca juices. Early cutting of one-year-old wood and early harvest were found to be the ideal combination for increasing quality. Full article

(This article belongs to the Section Viticulture)

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11 pages, 1445 KiB

Open AccessEditor’s ChoiceArticle

Hydroponic Basil Production: Temperature Influences Volatile Organic Compound Profile, but Not Overall Consumer Preference

by Kellie J. Walters and Roberto G. Lopez

Horticulturae 2022, 8(1), 76; https://doi.org/10.3390/horticulturae8010076 - 14 Jan 2022

Cited by 3 | Viewed by 2518

Abstract

Altering the growing temperature during controlled-environment production not only influences crop growth and development, but can also influence volatile organic compound (VOC) production and, subsequently, sensory attributes of culinary herbs. Therefore, the objectives of this study were to (1) quantify the influence of [...] Read more.

Altering the growing temperature during controlled-environment production not only influences crop growth and development, but can also influence volatile organic compound (VOC) production and, subsequently, sensory attributes of culinary herbs. Therefore, the objectives of this study were to (1) quantify the influence of mean daily temperature (MDT) and daily light integral (DLI) on key basil phenylpropanoid and terpenoid concentrations, (2) determine if differences in sensory characteristics due to MDT and DLI influence consumer preference, and (3) identify the sweet basil attributes consumers prefer. Thus, 2-week-old sweet basil ‘Nufar’ seedlings were transplanted into deep-flow hydroponic systems in greenhouses with target MDTs of 23, 26, 29, 32, or 35 °C and DLIs of 7, 9, or 12 mol·m⁻²·d⁻¹. After three weeks, the two most recently mature leaves were harvested for gas chromatography–mass spectrometry (GC–MS) and consumer sensory analysis. Panel evaluations were conducted through a sliding door with samples served individually while panelists answered Likert scale and open-ended quality attribute and sensory questions. The DLI did not influence VOC concentrations. Increasing MDT from 23 to 36 °C during production increased 1,8 cineole, eugenol, and methyl chavicol concentrations linearly and did not affect linalool concentration. The increases in phenylpropanoid (eugenol and methyl chavicol) were greater than increases in terpenoid (1,8 cineole) concentrations. However, these increases did not impact overall consumer or flavor preference. The MDT during basil production influenced appearance, texture, and color preference of panelists. Taken together, MDT during production influenced both VOC concentrations and textural and visual attribute preference of basil but did not influence overall consumer preference. Therefore, changing the MDT during production can be used to alter plant growth and development without significantly affecting consumer preference. Full article

(This article belongs to the Special Issue Urban Horticulture - New Trends and Technologies)

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11 pages, 3494 KiB

Open AccessEditor’s ChoiceArticle

Development of an Optical System Based on Spectral Imaging Used for a Slug Control Robot

by Christian Höing, Sharvari Raut, Abozar Nasirahmadi, Barbara Sturm and Oliver Hensel

Horticulturae 2022, 8(1), 77; https://doi.org/10.3390/horticulturae8010077 - 14 Jan 2022

Viewed by 2003

Abstract

The state-of-the-art technique to control slug pests in agriculture is the spreading of slug pellets. This method has some downsides, because slug pellets also harm beneficials and often fail because their efficiency depends on the prevailing weather conditions. This study is part of [...] Read more.

The state-of-the-art technique to control slug pests in agriculture is the spreading of slug pellets. This method has some downsides, because slug pellets also harm beneficials and often fail because their efficiency depends on the prevailing weather conditions. This study is part of a research project which is developing a pest control robot to monitor the field, detect slugs, and eliminate them. Robots represent a promising alternative to slug pellets. They work independent of weather conditions and can distinguish between pests and beneficials. As a prerequisite, a robot must be able to reliably identify slugs irrespective of the characteristics of the surrounding conditions. In this context, the utilization of computer vision and image analysis methods are challenging, because slugs look very similar to the soil, particularly in color images. Therefore, the goal of this study was to develop an optical filter-based system that distinguishes between slugs and soil. In this context, the spectral characteristics of both slugs and soil in the visible and visible near-infrared (VNIR) wavebands were measured. Conspicuous maxima followed by conspicuous local minima were found for the reflection spectra of slugs in the near infrared range from 850 nm to 990 nm]. Thus, this enabled differentiation between slugs and soils; soils showed a monotonic increase in the intensity of the relative reflection for this wavelength. The extrema determined in the reflection spectra of slugs were used to develop and set up a slug detector device consisting of a monochromatic camera, a filter changer and two narrow bandpass filters with nominal wavelengths of 925 nm and 975 nm. The developed optical system takes two photographs of the target area at night. By subtracting the pixel values of the images, the slugs are highlighted, and the soil is removed in the image due to the properties of the reflection spectra of soils and slugs. In the resulting image, the pixels of slugs were, on average, 12.4 times brighter than pixels of soil. This enabled the detection of slugs by a threshold method. Full article

(This article belongs to the Special Issue New Insights into Pest Management in Horticultural Production)

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16 pages, 3636 KiB

Open AccessEditor’s ChoiceArticle

Changes in Metal Distribution, Vegetative Growth, Reactive Oxygen and Nutrient Absorption of Tagetes patula under Soil Cadmium Stress

by Hongzhou Shi, Yangmei Wang, Hong Chen, Fuxiang Deng, Yongan Liu and Guoxing Cao

Horticulturae 2022, 8(1), 69; https://doi.org/10.3390/horticulturae8010069 - 12 Jan 2022

Cited by 6 | Viewed by 2201

Abstract

Phytoremediation with hyperaccumulator plants has been recognized as a potential way for the clearing of cadmium (Cd)-contaminated soil. In this study, hyperaccumulator Tagetes patula was treated with seven concentrations of Cd, ranging from 0 to 300 mg kg⁻¹. The Cd enrichment [...] Read more.

Phytoremediation with hyperaccumulator plants has been recognized as a potential way for the clearing of cadmium (Cd)-contaminated soil. In this study, hyperaccumulator Tagetes patula was treated with seven concentrations of Cd, ranging from 0 to 300 mg kg⁻¹. The Cd enrichment and nutrient contents in different organs during different growth phases were investigated. Under Cd concentrations ≤75 mg kg^-1, the morphological growth of T. patula did not change significantly regardless of growth stage. However, when Cd concentration exceeded 150 mg kg⁻¹, the morphological growth was remarkedly inhibited. The root/shoot ratio remained unchanged except for at 300 mg kg⁻¹. In addition, Cd negatively influenced the flowering process at the concentration of 300 mg kg⁻¹. Cd content increased significantly in Cd-treated plants. Nitrogen absorption was increased under Cd treatments, and phosphorus content was also increased under concentration ≤150 mg·kg⁻¹. However, the potassium content in the flower was decreased under 300 mg kg⁻¹. Furthermore, the contents of H₂O₂, O²⁻ and malondialdehyde were increased during the seedling phase, especially when Cd concentration was ≥150 mg kg⁻¹. In summary, T. patula showed a strong ability to tolerate Cd, and such ability might be explained by nutrient absorption and reactive oxygen clearness. Full article

(This article belongs to the Special Issue Phytotoxicity of Heavy Metals in Horticultural Plants and Security)

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13 pages, 3149 KiB

Open AccessEditor’s ChoiceArticle

Physiological, Transcriptomic Investigation on the Tea Plant Growth and Yield Motivation by Chitosan Oligosaccharides

by Lina Ou, Qiuqiu Zhang, Dezhong Ji, Yingying Li, Xia Zhou and Linhong Jin

Horticulturae 2022, 8(1), 68; https://doi.org/10.3390/horticulturae8010068 - 11 Jan 2022

Cited by 13 | Viewed by 2353

Abstract

Chitosan oligosaccharides (COS) has been abundantly studied for its application on regulating plant growth of many horticultural and agricultural crops. We presented here the effect of COS on tea plant growth and yield by physiological and transcriptomic checking. The results showed that COS [...] Read more.

Chitosan oligosaccharides (COS) has been abundantly studied for its application on regulating plant growth of many horticultural and agricultural crops. We presented here the effect of COS on tea plant growth and yield by physiological and transcriptomic checking. The results showed that COS treatment can enhance the antioxidant activity of superoxide dismutase (SOD) and peroxidase (POD) and increase the content of chlorophyll and soluble sugar in tea plants. The field trail results show that COS treatment can increase tea buds’ density by 13.81–23.16%, the weight of 100 buds by 15.94–18.15%, and the yield by 14.22–21.08%. Transcriptome analysis found 5409 COS-responsive differentially expressed genes (DEGs), including 3149 up-regulated and 2260 down-regulated genes, and concluded the possible metabolism pathway that responsible for COS promoting tea plant growth. Our results provided fundamental information for better understanding the molecular mechanisms for COS’s acting on tea plant growth and yield promotion and offer academic support for its practical application in tea plant. Full article

(This article belongs to the Special Issue Advances in Tea Plant Biology and Tea Quality Regulation)

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18 pages, 3709 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Salinity on Fruit Quality and Yield of Cherry Tomatoes

by Carlos Agius, Sabine von Tucher and Wilfried Rozhon

Horticulturae 2022, 8(1), 59; https://doi.org/10.3390/horticulturae8010059 - 8 Jan 2022

Cited by 23 | Viewed by 4869

Abstract

Hydroponic cultivation of vegetables avoids problems with soil-borne plant pathogens and may allow higher yield. In arid climates and particularly on islands, high concentrations of sodium chloride can be present in the groundwater. For instance, in many sites of Malta, the groundwater contains [...] Read more.

Hydroponic cultivation of vegetables avoids problems with soil-borne plant pathogens and may allow higher yield. In arid climates and particularly on islands, high concentrations of sodium chloride can be present in the groundwater. For instance, in many sites of Malta, the groundwater contains more than 10 mM sodium chloride. Here we investigated the effects of sodium chloride at levels typically found in Malta on yield, physiology and fruit quality of tomato, the economically most important vegetable. We selected cherry tomatoes since their production is attractive due to their high marketing value. While the yield declined at higher salinity levels tested (17 and 34 mM), the quality increased significantly as indicated by higher total soluble solids and fructose and glucose levels. The type of substrate—coco peat, perlite or Rockwool—had only minor effects. Although the concentration of citric acid and malic acid remained unaffected, the pH dropped by approximately 0.1 unit and the titratable acidity increased slightly. This might be explained by a high uptake of chloride but a lower increase of the sodium content and a reduced potassium level in the fruits, shifting the equilibrium of the organic acids more to their protonated forms. Proline increased significantly, while the level of glutamic acid, which is crucial for the taste, remained unchanged. Our results show that cherry tomatoes can be cultivated in nutrient solutions prepared with salt-containing groundwater, as found in Malta. The yield declined to some extent but the quality of the produced fruits was higher compared to cultivation in salt-free media. Full article

(This article belongs to the Special Issue Impact of Plant Nutrition on Primary and Secondary Metabolites)

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22 pages, 2288 KiB

Open AccessEditor’s ChoiceReview

Cyanobacteria: A Natural Source for Controlling Agricultural Plant Diseases Caused by Fungi and Oomycetes and Improving Plant Growth

by Hillary Righini, Ornella Francioso, Antera Martel Quintana and Roberta Roberti

Horticulturae 2022, 8(1), 58; https://doi.org/10.3390/horticulturae8010058 - 8 Jan 2022

Cited by 26 | Viewed by 5879

Abstract

Cyanobacteria, also called blue-green algae, are a group of prokaryotic microorganisms largely distributed in both terrestrial and aquatic environments. They produce a wide range of bioactive compounds that are mostly used in cosmetics, animal feed and human food, nutraceutical and pharmaceutical industries, and [...] Read more.

Cyanobacteria, also called blue-green algae, are a group of prokaryotic microorganisms largely distributed in both terrestrial and aquatic environments. They produce a wide range of bioactive compounds that are mostly used in cosmetics, animal feed and human food, nutraceutical and pharmaceutical industries, and the production of biofuels. Nowadays, the research concerning the use of cyanobacteria in agriculture has pointed out their potential as biofertilizers and as a source of bioactive compounds, such as phycobiliproteins, for plant pathogen control and as inducers of plant systemic resistance. The use of alternative products in place of synthetic ones for plant disease control is also encouraged by European Directive 2009/128/EC. The present up-to-date review gives an overall view of the recent results on the use of cyanobacteria for both their bioprotective effect against fungal and oomycete phytopathogens and their plant biostimulant properties. We highlight the need for considering several factors for a proper and sustainable management of agricultural crops, ranging from the mechanisms by which cyanobacteria reduce plant diseases and modulate plant resistance to the enhancement of plant growth. Full article

(This article belongs to the Special Issue Bioactivity, Phytochemical and Nutritional Composition of Natural Products)

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16 pages, 3378 KiB

Open AccessEditor’s ChoiceArticle

Effects of Yeast Product Addition and Fermentation Temperature on Lipid Composition, Taste and Mouthfeel Characteristics of Pinot Noir Wine

by Quynh Phan, Aubrey DuBois, James Osborne and Elizabeth Tomasino

Horticulturae 2022, 8(1), 52; https://doi.org/10.3390/horticulturae8010052 - 6 Jan 2022

Cited by 7 | Viewed by 2356

Abstract

Lipids have important impacts on wine sensory. By targeting the lipid sources in wine, mainly from grape tissues and yeast cell walls, it was possible to alter the wine lipid profile thus potentially changing the final product quality. This research examined the changes [...] Read more.

Lipids have important impacts on wine sensory. By targeting the lipid sources in wine, mainly from grape tissues and yeast cell walls, it was possible to alter the wine lipid profile thus potentially changing the final product quality. This research examined the changes of wine total lipids, lipid composition and sensory characteristics of Pinot noir wines in response to the winemaking factors, fermentation temperature and yeast product addition. Pinot noir grapes were fermented at 16 °C and 27 °C. After fermentation, Oenolees^® yeast product was added to the wines at three levels (0 g/L, 0.5 g/L and 1.0 g/L). The six wine treatments were subjected to chemical analyses measuring total lipids and an untargeted lipidomic approach analyzing lipid composition. High temperature fermentation wines had significantly higher total lipid content. Random forest analysis distinguished the wine groups based on the 25 main lipids, including free fatty acids, acylcarnitines, diglycerides, triglycerides and phospholipids. Taste and mouthfeel characteristics of each treatment were assessed using descriptive analysis and check-all-that-apply (CATA) techniques. Multivariate analyses showed that changing fermentation temperature significantly impacted sweetness and drying perception in Pinot noir wines. Yeast product addition had nuanced effects on wine lipid profiles and sensory perception. Full article

(This article belongs to the Special Issue Chemical Properties, Nutritional Quality, and Bioactive Components of Horticulture Food)

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10 pages, 2395 KiB

Open AccessEditor’s ChoiceArticle

Low CO₂ Levels Are Detrimental for In Vitro Plantlets through Disturbance of Photosynthetic Functionality and Accumulation of Reactive Oxygen Species

by Naser Askari, Sasan Aliniaeifard and Richard G. F. Visser

Horticulturae 2022, 8(1), 44; https://doi.org/10.3390/horticulturae8010044 - 4 Jan 2022

Cited by 13 | Viewed by 1711

Abstract

Photosynthesis of plantlets in tissue culture containers is not considered important, compared to photosynthesis of ex vitro plants, due to the exogenous source of carbohydrates present in tissue culture media. However, CO₂ starvation can generate a burst of reactive oxygen species (ROS). [...] Read more.

Photosynthesis of plantlets in tissue culture containers is not considered important, compared to photosynthesis of ex vitro plants, due to the exogenous source of carbohydrates present in tissue culture media. However, CO₂ starvation can generate a burst of reactive oxygen species (ROS). We examined this phenomenon in tissue culture, since CO₂ levels may become very low during the light period. The research was carried out with lily scales, regenerating adventitious bulblets, and with Arabidopsis seedlings. CO₂ starvation was achieved by placing a small vial of concentrated KOH solution in the culture container. CO₂ removal reduced the growth of regenerated lily bulblets by 33% or 23%, with or without sucrose in the medium, respectively. In Arabidopsis seedlings, CO₂ removal decreased growth by 50% or 78% in the presence or absence of sucrose in the medium, respectively. Therefore, the addition of sucrose as a replacement for photosynthesis resulted in only partial recovery of growth. Staining with nitroblue tetrazolium (NBT) showed little to no ROS in ex vitro growing seedlings, while abundant ROS were detected in seedlings grown under in vitro CO₂ starvation. Seedlings grown under normal tissue culture conditions (no CO₂ withdrawal) showed low levels of ROS. In lily tissue culture, CO₂ starvation decreased the maximum quantum efficiency of photosystem II (F_v/F_m) from 0.69 to 0.60, and in Arabidopsis from 0.76 to 0.62. F_v/F_m of ex vitro lily and Arabidopsis seedlings was 0.77 and 0.79, respectively. This is indicative of a disturbance in photosynthesis functionality and the occurrence of in vitro stress under reduced CO₂ concentrations. We conclude that poor growth, in the absence of CO₂, was partly due to strongly reduced photosynthesis, while the detrimental effects were most likely due to a burst of ROS. Full article

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18 pages, 2348 KiB

Open AccessEditor’s ChoiceArticle

Transcriptomic Analysis of Sex-Associated DEGs in Female and Male Flowers of Kiwifruit (Actinidia deliciosa [A. Chev] C. F. Liang & A. R. Ferguson)

by Patricio Zapata, Makarena González, Igor Pacheco, Claudia Jorquera, Claudia Silva-Andrade, Marco Isaac Garrido, Rodrigo Infante and Juan Alfonso Salazar

Horticulturae 2022, 8(1), 38; https://doi.org/10.3390/horticulturae8010038 - 30 Dec 2021

Viewed by 26549

Abstract

Kiwifruit (Actinidia deliciosa [A. Chev.], C.V. Liang & A. R. Ferguson, 1984) is a perennial plant, with morphologically hermaphroditic and functionally dioecious flowers. Fruits of this species are berries of great commercial and nutritional importance. Nevertheless, few studies have analyzed the molecular [...] Read more.

Kiwifruit (Actinidia deliciosa [A. Chev.], C.V. Liang & A. R. Ferguson, 1984) is a perennial plant, with morphologically hermaphroditic and functionally dioecious flowers. Fruits of this species are berries of great commercial and nutritional importance. Nevertheless, few studies have analyzed the molecular mechanisms involved in sexual differentiation in this species. To determine these mechanisms, we performed RNA-seq in floral tissue at stage 60 on the BBCH scale in cultivar ‘Hayward’ (H, female) and a seedling from ‘Green Light’ × ‘Tomuri’ (G × T, male). From these analyses, we obtained expression profiles of 24,888 (H) and 27,027 (G × T) genes, of which 6413 showed differential transcript abundance. Genetic ontology (GO) and KEGG analysis revealed activation of pathways associated with the translation of hormonal signals, plant-pathogen interaction, metabolism of hormones, sugars, and nucleotides. The analysis of the protein-protein interaction network showed that the genes ERL1, AG, AGL8, LFY, WUS, AP2, WRKY, and CO, are crucial elements in the regulation of the hormonal response for the formation and development of anatomical reproductive structures and gametophytes. On the other hand, genes encoding four Putative S-adenosyl-L-methionine-dependent methyltransferases (Achn201401, Achn281971, Achn047771 and Achn231981) were identified, which were up-regulated mainly in the male flowers. Moreover, the expression profiles of 15 selected genes through RT-qPCR were consistent with the results of RNA-seq. Finally, this work provides gene expression-based interactions between transcription factors and effector genes from hormonal signaling pathways, development of floral organs, biological and metabolic processes or even epigenetic mechanisms which could be involved in the kiwi sex-determination. Thus, in order to decode the nature of these interactions, it could be helpful to propose new models of flower development and sex determination in the Actinidia genus. Full article

(This article belongs to the Special Issue Physiology and Molecular Biology of Flowering, Fruit Setting, Fruit Quality)

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15 pages, 3252 KiB

Open AccessEditor’s ChoiceArticle

Anticancer Activity of Moringa peregrina (Forssk.) Fiori.: A Native Plant in Traditional Herbal Medicine of the United Arab Emirates

by Salama Khamis Sultan Al Kaabi, Annadurai Senthilkumar, Jaleel Kizhakkayil, Mohammed Abdul Muhsen Alyafei, Shyam Sreedhara Kurup, Ayesha S. Al Dhaheri and Abdul Jaleel

Horticulturae 2022, 8(1), 37; https://doi.org/10.3390/horticulturae8010037 - 30 Dec 2021

Cited by 2 | Viewed by 2451

Abstract

Moringa peregrina (Forssk.) Fiori. is a native desert tree growing in United Arab Emirates (UAE). The plant is being cultivated in many parts of UAE, owing to its uses in traditional medicinal and food systems. In the present study bioactivities of cultivated M. [...] Read more.

Moringa peregrina (Forssk.) Fiori. is a native desert tree growing in United Arab Emirates (UAE). The plant is being cultivated in many parts of UAE, owing to its uses in traditional medicinal and food systems. In the present study bioactivities of cultivated M. peregrina species samples are evaluated with cytotoxic studies in the human breast cancer cell line (MCF-7) and human colon adenocarcinoma cell line (Caco-2). Different extracts with hexane, chloroform, acetone and methanol were prepared from tubers, leaves and stem of M. peregrina for estimating their antioxidant contents and anticancer activities. The study was performed at different concentrations and all the extracts showed dose-depended response on both the cell lines. Among the extracts tested, the chloroform extract of stem showed remarkable anti-proliferative/cell death activity (IC₅₀ = 45.53 µg/mL of 48 h incubation and 33.32 µg/mL of 72 h incubation) on MCF-7 cell lines. Whereas the same extract showed comparatively less activity (IC₅₀ = 93.75 µg/mL of 48 h incubation and 87.76 µg/mL of 72 h incubation) on Caco-2 cell lines. The anti-proliferative effect of leaf extract with chloroform showed a drastic change in cell viability from 48 to 72 h incubation, in MCF-7 cells 220 to 87.5 µg/mL and in Caco-2 cells 500.9 to 72.9 µg/mL, respectively. Moreover, less than 200 µg/mL of IC₅₀ values reported in hexane extracts of tubers (188.6 µg/mL for 48 h and 164.3 µg/mL for 72 h), acetone extracts of tubers (167.4 µg/mL for 72 h) and acetone extracts of stem (171.5 µg/mL for 48 h and 101.7 µg/mL for 72 h) on MCF-7 cells. PARP (Poly (ADP-ribose) polymerase) cleavage assay and DNA fragmentation assay performed to understand the cause of cell death. Treatment of extract on the normal fibroblast cell line required more concentration for cytotoxicity compared to the treatment on the cancer cells. This ability of the extract proved the anti-cancer property of the M. peregrina extract from the stem, tuber and leaves. The information provided in the present study enables further studies on the isolation and characterization of an anticancer molecule from the tubers of M. peregrina. Full article

(This article belongs to the Special Issue Botany, Phytochemistry and Pharmacology in Traditional Herbal Medicine)

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11 pages, 2767 KiB

Open AccessEditor’s ChoiceArticle

Biocontrol of Large Patch Disease in Zoysiagrass (Zoysia japonica) by Bacillus subtilis SA-15: Identification of Active Compounds and Synergism with a Fungicide

by Young-Sun Kim, Kyo-Suk Lee, Hong-Gi Kim and Geung-Joo Lee

Horticulturae 2022, 8(1), 34; https://doi.org/10.3390/horticulturae8010034 - 29 Dec 2021

Cited by 4 | Viewed by 1854

Abstract

Bacillus subtilis SA-15 is a plant growth-promoting bacterium isolated from non-farming soil. We aimed to identify lipopeptides produced by B. subtilis SA-15 and evaluate the control efficacy of B. subtilis SA-15 against large patch disease caused by Rhizoctonia solani AG 2-2 (IV) in [...] Read more.

Bacillus subtilis SA-15 is a plant growth-promoting bacterium isolated from non-farming soil. We aimed to identify lipopeptides produced by B. subtilis SA-15 and evaluate the control efficacy of B. subtilis SA-15 against large patch disease caused by Rhizoctonia solani AG 2-2 (IV) in zoysiagrass (Zoysia japonica). Bacillus subtilis SA-15 inhibited mycelial growth of R. solani AG 2-2 (IV) in vitro and produced fengycin A and dehydroxyfengycin A, which are antifungal compounds. Fengycin A and deghydroxyfengycin A inhibited R. solani mycelial growth by 30.4 and 63.2%, respectively. We formulated B. subtilis SA-15 into a wettable powder and determined its control efficiency against large patch in a field trial. The control efficacy was 51.2–92.0%. Moreover, when B. subtilis SA-15 powder was applied together with half the regular dose of the fungicide pecycuron, the control efficacy was 88.5–100.0%. These results indicate that B. subtilis SA-15 can be used to control soil-borne diseases, including large patch caused by R. solani, because of lipopeptide production. The use of this bacterium can also reduce the amount of fungicide needed, providing an eco-friendly management option for turfgrass. Full article

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21 pages, 1971 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Pheno-Morphological and Essential Oil Composition Responses to UVA Radiation and Protectants: A Case Study in Three Thymus Species

by Hasan Mumivand, Alireza Shayganfar, Georgios Tsaniklidis, Zohreh Emami Bistgani, Dimitrios Fanourakis and Silvana Nicola

Horticulturae 2022, 8(1), 31; https://doi.org/10.3390/horticulturae8010031 - 29 Dec 2021

Cited by 9 | Viewed by 2045

Abstract

Solar ultraviolet (UV) radiation mainly includes UVA (320–400 nm). UVA intensity varies depending on the season and geographic location, while it is projected to rise owing to climate change. Since it elicits secondary metabolism, additional knowledge on the UVA dependence of phytochemical production [...] Read more.

Solar ultraviolet (UV) radiation mainly includes UVA (320–400 nm). UVA intensity varies depending on the season and geographic location, while it is projected to rise owing to climate change. Since it elicits secondary metabolism, additional knowledge on the UVA dependence of phytochemical production is required for both farmers and processors, particularly under natural settings. In this field study, the pheno-morphological traits and essential oil composition responses to UVA intensity were addressed in three Thymus species [T. daenensis (endemic to Iran), T. fedtschenkoi (semi-endemic), T. vulgaris (common thyme)]. During growth, three UVA levels (ambient, enriched, excluded) were realized in combination with spraying protectants [water (control), melatonin, glutathione, iron-zinc nanofertilizer]. In T. daenensis, enriched UVA caused early flowering. The height of T. daenensis was the longest under enriched UVA, and the shortest under excluded UVA. In control plants, enriched and excluded UVA stimulated the accumulation of oxygenated metabolites in T. daenensis and T. fedtschenkoi. Altogether, under enriched UVA some phenolic compounds (e.g., thymol, carvacrol, γ-terpinene) increased in the essential oil of all three species, but others decreased. In all taxa, glutathione caused a significant essential oil content reduction. Iron-zinc nanofertilizer increased essential oil accumulation in T. daenensis and T. vulgaris. Treatments also induced an alteration of the essential oil composition. In conclusion, cultivation regime effects on the essential oil quality (composition) and quantity were strongly species dependent. T. deanensis underwent the most consistent enhancement under UVA, making the species more adaptable to climate change, whereas T. fedtschenkoi the least. Full article

(This article belongs to the Special Issue New Trends and Innovations in Medicinals, Herbs, and Specialty Crops)

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13 pages, 18346 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effects of Selenium on the Chlorophylls, Gas Exchange, Antioxidant Activity and Amino Acid Composition of Lettuce Grown under an Aquaponics System

by María Carmen Piñero, Ginés Otálora, Jacinta Collado-González, Josefa López-Marín and Francisco M. del Amor

Horticulturae 2022, 8(1), 30; https://doi.org/10.3390/horticulturae8010030 - 28 Dec 2021

Cited by 10 | Viewed by 2229

Abstract

Aquaponics is a sustainable technique that is respectful to the environment, as it reuses products and minimizes the consumption of new materials. The combination of this technique with the foliar application of selenium (as Na₂SeO₄) could lead to healthier [...] Read more.

Aquaponics is a sustainable technique that is respectful to the environment, as it reuses products and minimizes the consumption of new materials. The combination of this technique with the foliar application of selenium (as Na₂SeO₄) could lead to healthier and more sustainable products, which are increasingly requested by consumers. Lettuce (Lactuca sativa L.) plants were grown in an aquaponics system (fish water) as compared with a control (conventional soilless fertigation), and sprayed with different concentrations of selenium (0, 4, 8, and 16 µmol L⁻¹). The results showed a reduction in the dry weight and N content of lettuce plants irrigated with the fish water mixture treatment. However, the application of Se relieved this stress, increasing the photosynthetic rate and ABTS, and reducing the content of chlorophylls, β-carotene, and several of the measured amino acids. The best results were observed with the highest concentration of Se (16 µmol L⁻¹), as an increase in nitrogen content was observed, as shown by a greater weight of the plant. Furthermore, this treatment produced the greatest increase in ABTS and the least reduction in amino acid content. This novel study highlights the possibility of improving the efficiency of N utilization in lettuce by applying foliar selenium in combination with an aquaponics system. Full article

(This article belongs to the Collection Recent Advances in Hydroponic and Aquaponic Research)

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15 pages, 1976 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Analysis of Compounds with Oenological Interest in Somatic Variants of Grapevines

by Ana Jiménez-Cantizano, Pau Sancho-Galán, Gerardo F. Barbero, Víctor Palacios and Antonio Amores-Arrocha

Horticulturae 2022, 8(1), 22; https://doi.org/10.3390/horticulturae8010022 - 24 Dec 2021

Cited by 1 | Viewed by 2257

Abstract

Grapevine varieties can be identified genetically by microsatellite markers. However, these molecular markers are not available to discriminate between somatic mutations that give rise to clones. Therefore, the study of compounds with oenological interest could be used to identify variability in grapevine somatic [...] Read more.

Grapevine varieties can be identified genetically by microsatellite markers. However, these molecular markers are not available to discriminate between somatic mutations that give rise to clones. Therefore, the study of compounds with oenological interest could be used to identify variability in grapevine somatic variants. In this research, sugars (glucose, fructose), acids (tartaric and malic acid) and polyphenols (22 phenolic compounds, including 13 anthocyanins) were analyzed in grape berries of two somatic variants known with different names—‘Graciano’ and ‘Tintilla de Rota’—cultivated in the same vineyard under warm climate conditions. The organic acid results show significant differences between the performance of the two accessions. Regarding phenolic compound (excluding anthocyanins) content, significant differences were observed between the two accessions. Kaempferol, caftaric acid and epicatechin were the compounds responsible for the reported differences. Differences in anthocyanin content showed opposite behavior between ‘Tintilla de Rota’ and ‘Graciano’. In this sense, ‘Graciano’ accession showed an increase in all forms of anthocyanins, with a remarkable increment of peonidin 3-O-glucoside. Principal component analysis of polyphenolic compounds revealed clearly distinguished behaviors concerning these compounds, besides showing similar tendencies between the two accessions during the ripening stage. These results could allow for the discrimination of the two accessions into somatic variants highlighting their individual identity. Full article

(This article belongs to the Special Issue Grapevine Breeding and Oenological Potential)

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15 pages, 9039 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Transcriptional Association between mRNAs and Their Paired Natural Antisense Transcripts Following Fusarium oxysporum Inoculation in Brassica rapa L.

by Mst. Arjina Akter, Hasan Mehraj, Naomi Miyaji, Satoshi Takahashi, Takeshi Takasaki-Yasuda, Motoaki Seki, Elizabeth S. Dennis, Ryo Fujimoto and Kenji Osabe

Horticulturae 2022, 8(1), 17; https://doi.org/10.3390/horticulturae8010017 - 23 Dec 2021

Cited by 5 | Viewed by 3256

Abstract

Long noncoding RNAs (lncRNAs) play important roles in abiotic and biotic stress responses; however, studies on the mechanism of regulation of lncRNA expression are limited in plants. The present study examined the relationship between lncRNA expression level and two active histone modifications (H3K4me3 [...] Read more.

Long noncoding RNAs (lncRNAs) play important roles in abiotic and biotic stress responses; however, studies on the mechanism of regulation of lncRNA expression are limited in plants. The present study examined the relationship between lncRNA expression level and two active histone modifications (H3K4me3 and H3K36me3) in Brassica rapa. Both histone marks were enriched in the chromatin regions encoding lncRNAs, especially around the transcription start site. The transcription level of long intergenic noncoding RNAs was positively associated with the level of H3K4me3 and H3K36me3, while this association was not observed in natural antisense RNAs (NATs) and intronic noncoding RNAs. As coordinate expression of mRNAs and paired NATs under biotic stress treatment has been identified, the transcriptional relationship between mRNAs and their paired NATs following Fusarium oxysporum f. sp. conglutinans (Foc) inoculation was examined. A positive association of expression levels between mRNAs and their paired NATs following Foc inoculation was observed. This association held for several defense-response-related genes and their NAT pairs. These results suggest that coordinate expression of mRNAs and paired NATs plays a role in the defense response against Foc. Full article

(This article belongs to the Special Issue Advances of Molecular Breeding for the Vegetable Crops in the Genomic Era)

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19 pages, 3409 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Novel Target (Oxidation Resistant 2) in Arabidopsis thaliana to Reduce Clubroot Disease Symptoms via the Salicylic Acid Pathway without Growth Penalties

by Regina Mencia, Elina Welchen, Susann Auer and Jutta Ludwig-Müller

Horticulturae 2022, 8(1), 9; https://doi.org/10.3390/horticulturae8010009 - 22 Dec 2021

Cited by 4 | Viewed by 2999

Abstract

The clubroot disease (Plasmodiophora brassicae) is one of the most damaging diseases worldwide among brassica crops. Its control often relies on resistant cultivars, since the manipulation of the disease hormones, such as salicylic acid (SA) alters plant growth negatively. Alternatively, the [...] Read more.

The clubroot disease (Plasmodiophora brassicae) is one of the most damaging diseases worldwide among brassica crops. Its control often relies on resistant cultivars, since the manipulation of the disease hormones, such as salicylic acid (SA) alters plant growth negatively. Alternatively, the SA pathway can be increased by the addition of beneficial microorganisms for biocontrol. However, this potential has not been exhaustively used. In this study, a recently characterized protein Oxidation Resistant 2 (OXR2) from Arabidopsis thaliana is shown to increase the constitutive pathway of SA defense without decreasing plant growth. Plants overexpressing AtOXR2 (OXR2-OE) show strongly reduced clubroot symptoms with improved plant growth performance, in comparison to wild type plants during the course of infection. Consequently, oxr2 mutants are more susceptible to clubroot disease. P. brassicae itself was reduced in these galls as determined by quantitative real-time PCR. Furthermore, we provide evidence for the transcriptional downregulation of the gene encoding a SA-methyltransferase from the pathogen in OXR2-OE plants that could contribute to the phenotype. Full article

(This article belongs to the Special Issue Soil-Borne Obligate Parasite of Brassicaceae)

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17 pages, 3096 KiB

Open AccessEditor’s ChoiceArticle

Assessing the Potential of Sentinel-2 Derived Vegetation Indices to Retrieve Phenological Stages of Mango in Ghana

by Benjamin Adjah Torgbor, Muhammad Moshiur Rahman, Andrew Robson, James Brinkhoff and Azeem Khan

Horticulturae 2022, 8(1), 11; https://doi.org/10.3390/horticulturae8010011 - 22 Dec 2021

Cited by 10 | Viewed by 5388

Abstract

In 2020, mango (Mangifera indica) exports contributed over 40 million tons, worth around US$20 billion, to the global economy. Only 10% of this contribution was made from African countries including Ghana, largely due to lower investment in the sector and general [...] Read more.

In 2020, mango (Mangifera indica) exports contributed over 40 million tons, worth around US$20 billion, to the global economy. Only 10% of this contribution was made from African countries including Ghana, largely due to lower investment in the sector and general paucity of research into the mango value chain, especially production, quality and volume. Considering the global economic importance of mango coupled with the gap in the use of the remote sensing technology in the sector, this study tested the hypothesis that phenological stages of mango can be retrieved from Sentinel-2 (S2) derived time series vegetation indices (VIs) data. The study was conducted on four mango farms in the Yilo Krobo Municipal Area of Ghana. Seasonal (temporal) growth curves using four VIs (NDVI, GNDVI, EVI and SAVI) for the period from 2017 to 2020 were derived for each of the selected orchards and then aligned with five known phenology stages: Flowering/Fruitset (F/FS), Fruit Development (FRD), Maturity/Harvesting (M/H), Flushing (FLU) and Dormancy (D). The significance of the variation “within” and “between” farms obtained from the VI metrics of the S2 data were tested using single-factor and two-factor analysis of variance (ANOVA). Furthermore, to identify which specific variable pairs (phenology stages) were significantly different, a Tukey honest significant difference (HSD) post-hoc test was conducted, following the results of the ANOVA. Whilst it was possible to differentiate the phenological stages using all the four VIs, EVI was found to be the best related with p < 0.05 for most of the studied farms. A distinct annual trend was identified with a peak in June/July and troughs in December/January. The derivation of remote sensing based ‘time series’ growth profiles for commercial mango orchards supports the ‘benchmarking’ of annual and seasonal orchard performance and therefore offers a near ‘real time’ technology for identifying significant variations resulting from pest and disease incursions and the potential impacts of seasonal weather variations. Full article

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13 pages, 1761 KiB

Open AccessEditor’s ChoiceArticle

High NH₄⁺/NO₃⁻ Ratio Inhibits the Growth and Nitrogen Uptake of Chinese Kale at the Late Growth Stage by Ammonia Toxicity

by Yudan Wang, Xiaoyun Zhang, Houcheng Liu, Guangwen Sun, Shiwei Song and Riyuan Chen

Horticulturae 2022, 8(1), 8; https://doi.org/10.3390/horticulturae8010008 - 22 Dec 2021

Cited by 13 | Viewed by 2682

Abstract

The aim of this study was to determine the effects of various NH₄⁺/NO₃⁻ ratios in a nutrient solution on the growth and nitrogen uptake of Chinese kale under hydroponic conditions. The four NH₄⁺/NO₃⁻ [...] Read more.

The aim of this study was to determine the effects of various NH₄⁺/NO₃⁻ ratios in a nutrient solution on the growth and nitrogen uptake of Chinese kale under hydroponic conditions. The four NH₄⁺/NO₃⁻ ratios in the nutrient solution were CK (0/100), T1 (10/90), T2 (25/75), and T3 (50/50). An appropriate NH₄⁺/NO₃⁻ ratio (10/90, 25/75) promoted the growth of Chinese kale. T2 produced the highest fresh and dry weight among treatments, and all indices of seedling root growth were the highest under T2. A high NH₄⁺/NO₃⁻ ratio (50/50) promoted the growth of Chinese kale seedlings at the early stage but inhibited growth at the late growth stage. At harvest, the nutrient solution showed acidity. The pH value was the lowest in T3, whereas NH₄⁺ and NH₄⁺/NO₃⁻ ratios were the highest, which caused ammonium toxicity. Total N accumulation and N use efficiency were the highest in T2, and total N accumulation was the lowest in T3. Principal component analysis showed that T2 considerably promoted growth and N absorption of Chinese kale, whereas T3 had a remarkable effect on the pH value. These findings suggest that an appropriate increase in NH₄⁺ promotes the growth and nutrient uptake of Chinese kale by maintaining the pH value and NH₄⁺/NO₃⁻ ratios of the nutrient solution, whereas excessive addition of NH₄⁺ may induce rhizosphere acidification and ammonia toxicity, inhibiting plant growth. Full article

(This article belongs to the Special Issue Greenhouse Management for Better Vegetable Quality, Higher Nutrient Use Efficiency and Healthier Soil)

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21 pages, 5694 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Fruit Quality and Yield of Three Highbush Blueberry (Vaccinium corymbosum L.) Cultivars Grown in Two Planting Systems under Different Protected Environments

by Tina Smrke, Robert Veberic, Metka Hudina, Vid Zitko, Mitja Ferlan and Jerneja Jakopic

Horticulturae 2021, 7(12), 591; https://doi.org/10.3390/horticulturae7120591 - 20 Dec 2021

Cited by 9 | Viewed by 3364

Abstract

Due to the increasing interest in highbush blueberry (Vaccinium corymbosum L.) among consumers, together with the problems of climate change and specific substrate requirements, a novel approach to intensive blueberry production is required. Here, ‘Duke’, ‘Aurora’, and ‘Brigitta’ blueberry cultivars were planted [...] Read more.

Due to the increasing interest in highbush blueberry (Vaccinium corymbosum L.) among consumers, together with the problems of climate change and specific substrate requirements, a novel approach to intensive blueberry production is required. Here, ‘Duke’, ‘Aurora’, and ‘Brigitta’ blueberry cultivars were planted under the protective environments of a high tunnel and black hail net, each using ridge and pot planting systems. The high tunnel increased the maximal air temperature on average by 7.2 °C compared to the hail net. For all three cultivars, harvest began 6 to 18 days earlier under the high tunnel than under the hail net; however, lower yields and individual phenolics contents were obtained for the fruit. In ‘Aurora’ and ‘Brigitta’, environmental conditions under the high tunnel also reduced plant volume and fruit sugar/organic acid ratio. Growing blueberry plants in 60 L pots had no negative effects on plant volume and fruit ripening time, yield, firmness, color, and chemical composition. This study represents the first to compare highbush blueberry grown under the high tunnel and hail net protective environments using ridge and pot planting systems across three different cultivars. Here, we can conclude that optimal highbush blueberry production of ‘Duke’, ‘Aurora’, and ‘Brigitta’ under the climate conditions of the study provides earlier ripening times under the high tunnel. However, according to fruit yield and quality, all three cultivars benefit from the hail net over the high tunnel, while ‘Duke’ and ‘Brigitta’ also benefit in particular from the hail net combined with growth in pots. Full article

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11 pages, 1431 KiB

Open AccessEditor’s ChoiceArticle

Characterization of Genomic Variation from Lotus (Nelumbo Adans.) Mutants with Wide and Narrow Tepals

by Fengluan Liu, Mi Qin, Shuo Li, Dasheng Zhang, Qingqing Liu, Mengxiao Yan and Daike Tian

Horticulturae 2021, 7(12), 593; https://doi.org/10.3390/horticulturae7120593 - 20 Dec 2021

Viewed by 2783

Abstract

Compared with rose, chrysanthemum, and water lily, the absence of short-wide and long-narrow tepals of ornamental lotus (Nelumbo Adans.) limits the commercial value of flowers. In this study, the genomes of two groups of lotus mutants with wide-short and narrow-long tepals were [...] Read more.

Compared with rose, chrysanthemum, and water lily, the absence of short-wide and long-narrow tepals of ornamental lotus (Nelumbo Adans.) limits the commercial value of flowers. In this study, the genomes of two groups of lotus mutants with wide-short and narrow-long tepals were resequenced to uncover the genomic variation and candidate genes associated with tepal shape. In group NL (short for N. lutea, containing two mutants and one control of N. lutea), 716,656 single nucleotide polymorphisms (SNPs) and 221,688 insertion-deletion mutations (Indels) were obtained, while 639,953 SNPs and 134,6118 Indels were obtained in group WSH (short for ‘Weishan Hong’, containing one mutant and two controls of N. nucifera ‘Weishan Hong’). Only a small proportion of these SNPs and Indels was mapped to exonic regions of genome: 1.92% and 0.47%, respectively, in the NL group, and 1.66% and 0.48%, respectively, in the WSH group. Gene Ontology (GO) analysis showed that out of 4890 (NL group) and 1272 (WSH group) annotated variant genes, 125 and 62 genes were enriched (Q < 0.05), respectively. Additionally, in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, 104 genes (NL group) and 35 genes (WSH group) were selected (p < 0.05). Finally, there were 306 candidate genes that were sieved to determine the development of tepal shape in lotus plants. It will be an essential reference for future identification of tepal-shaped control genes in lotus plants. This is the first comprehensive report of genomic variation controlling tepal shape in lotus, and the mutants in this study are promising materials for breeding novel lotus cultivars with special tepals. Full article

(This article belongs to the Special Issue Genetic Improvement of Horticultural Plants with Special Emphasis on Ornamentals)

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16 pages, 1064 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effects of Individual and Simultaneous Selenium and Iodine Biofortification of Baby-Leaf Lettuce Plants Grown in Two Different Hydroponic Systems

by Martina Puccinelli, Fernando Malorgio, Luca Incrocci, Irene Rosellini and Beatrice Pezzarossa

Horticulturae 2021, 7(12), 590; https://doi.org/10.3390/horticulturae7120590 - 19 Dec 2021

Cited by 12 | Viewed by 3504

Abstract

The iodine (I) and selenium (Se) deficiencies affect approximately 30% and 15%, respectively, of the global population. The biofortification of vegetables is a valid way to increase the intake of iodine and selenium through the diet. This study was carried out on baby-leaf [...] Read more.

The iodine (I) and selenium (Se) deficiencies affect approximately 30% and 15%, respectively, of the global population. The biofortification of vegetables is a valid way to increase the intake of iodine and selenium through the diet. This study was carried out on baby-leaf lettuce to investigate the effects on plant growth, leaf quality, and leaf I and Se accumulation of adding potassium iodide and sodium selenate, separately and simultaneously, to the nutrient solution in a floating system and aeroponics. The effect of I and Se biofortification on post-harvest quality of lettuce leaves was also evaluated. Our results evidenced that the Se and I treatments increased the content of the two microelements in lettuce leaves without any negative interactions in the plants, when applied either separately or simultaneously. Both hydroponic systems proved to be suitable for producing Se and/or I enriched lettuce. Biofortification with Se was more effective when performed in aeroponics, whereas I biofortification was more effective in the floating system. Quality of leaves during post-harvest storage was not affected by neither of the treatments. Lettuce leaves enriched with 13 µM Se and 5 µMI could be good dietary sources of Se and I without inducing toxic effects in humans. Full article

(This article belongs to the Special Issue Hydroponics in Vegetable Production)

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19 pages, 5754 KiB

Open AccessEditor’s ChoiceArticle

Monitoring the Green Vegetation Period of Two Narcissus Taxa by Non-Destructive Analysis of Selected Physiological and Morphological Properties

by Katalin Jezdinská Slezák, Aleš Jezdinský, Miroslav Vachůn, Oldřiška Sotolářová, Robert Pokluda and Jiří Uher

Horticulturae 2021, 7(12), 585; https://doi.org/10.3390/horticulturae7120585 - 17 Dec 2021

Cited by 2 | Viewed by 2285

Abstract

In a pot experiment, an early-flowering Narcissus pseudonarcissus cv. ‘Dutch Master’ (DM) and late-flowering N. poeticus cultural form (PO) were examined. The photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), photosynthetic water use efficiency (WUE), relative chlorophyll content (CCI) and chlorophyll fluorescence [...] Read more.

In a pot experiment, an early-flowering Narcissus pseudonarcissus cv. ‘Dutch Master’ (DM) and late-flowering N. poeticus cultural form (PO) were examined. The photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), photosynthetic water use efficiency (WUE), relative chlorophyll content (CCI) and chlorophyll fluorescence (F) were measured regularly. Leaf length, scape length and weight of the plant organs were also measured. The DM cultivar had higher gs and lower E values than the PO on most measuring dates (season average: gs: DM: 165.34, PO: 123.63; E: DM: 1.39, PO: 1.78 mmol H₂O m⁻²s⁻¹). The A curve was similar for the two taxa, except for the first measuring dates. The basic F values (F0, Fm, Fv) for DM were lower and CCI values were higher than for PO (season average of CCI: DM: 94.82, PO: 60.34). The Fm/F0, Fv/F0 and CCI curves were well described by a second order equation. The seasonal change of F and CCI values was the greatest for both taxa near the leaf tip. Bulb growth occurred in the two taxa in approximately the same calendar period, regardless of flowering time. A significant part of the leaf growth in DM occurred after flowering, while the leaves of PO reached their mature size by flowering. Full article

(This article belongs to the Special Issue Factors Affecting Export Flower Quality and Strategies for Prolonging Flowers Vase Life)

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12 pages, 2536 KiB

Open AccessEditor’s ChoiceArticle

Effect of Different Temperature Regimes on the Germination of Pseudolysimachion pusanensis (Y. N. Lee) Y. N. Lee Seeds

by Mi-Hyun Lee, Jin-Hyun Lim, Cho-Hee Park, Jun-Hyeok Kim and Chae-Sun Na

Horticulturae 2021, 7(12), 577; https://doi.org/10.3390/horticulturae7120577 - 14 Dec 2021

Cited by 1 | Viewed by 2355

Abstract

In this study, we determined the germination response in the seeds of the rare plant Pseudolysimachion pusanensis (Y. N. Lee) Y. N. Lee to different temperatures. P. pusanensis seeds were collected from the Baekdudaegan National Arboretum, South Korea, in November 2019, and dried. [...] Read more.

In this study, we determined the germination response in the seeds of the rare plant Pseudolysimachion pusanensis (Y. N. Lee) Y. N. Lee to different temperatures. P. pusanensis seeds were collected from the Baekdudaegan National Arboretum, South Korea, in November 2019, and dried. Dry seeds were placed at constant and alternating temperatures (5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C, and 35 °C) to determine their germination percentage (GP). The seeds were exposed to 59 temperature combinations ranging from 5 °C to 43 °C using a thermal gradient plate. The photoperiod was set at 12:12 h (light:dark) and germination assays were performed five times a week. Subsequently, the seed GP and the number of days required to reach 50% of the germination (T₅₀) were determined. The highest final GP was 94.38%, with a T₅₀ value of 9.26 d at 15 °C. However, the mean germination time was 12.5 d at 15 °C, and linear regression using 1/T₅₀ revealed that the base temperature ranged from 2.69 °C to 4.68 °C. These results for P. pusanensis seeds stored in a seed bank provide useful data for the native plants horticulture industry and can also be utilized for storage management. Full article

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13 pages, 3323 KiB

Open AccessEditor’s ChoiceArticle

Dynamics of Energy Metabolism in Carbon Starvation-Induced Fruitlet Abscission in Litchi

by Qian Wu, Xingshuai Ma, Qingxin Chen, Ye Yuan, Huicong Wang, Xinhua He, Minglei Zhao and Jianguo Li

Horticulturae 2021, 7(12), 576; https://doi.org/10.3390/horticulturae7120576 - 14 Dec 2021

Viewed by 2512

Abstract

Fruit abscission is triggered by multiple changes in endogenous components of the fruit, including energy metabolism. However, it is still unknown how the core energy metabolism pathways are modified during fruit abscission. Here, we investigated the relationship between carbon starvation-induced fruitlet abscission and [...] Read more.

Fruit abscission is triggered by multiple changes in endogenous components of the fruit, including energy metabolism. However, it is still unknown how the core energy metabolism pathways are modified during fruit abscission. Here, we investigated the relationship between carbon starvation-induced fruitlet abscission and energy metabolism changes in litchi. The fruitlet abscission of litchi ‘Feizixiao’ was induced sharply by girdling plus defoliation (GPD), a carbon stress treatment. Using liquid chromatography tandem mass spectrometry (LC-MS/MS) targeted metabolomics analysis, we identified a total of 21 metabolites involved in glycolysis, TCA cycle and oxidative phosphorylation pathways. Among them, the content of most metabolites in glycolysis pathways and TCA cycles was reduced, and the activity of corresponding metabolic enzymes such as ATP-dependent phosphofructokinase (ATP-PFK), pyruvate kinase (PK), citrate synthase (CS), succinate thiokinase (SAT), and NAD-dependent malate dehydrogenase (NAD-MDH) was decreased. Consistently, we further showed that the expression of the relative genes (LcPFK2, LcPK2, LcPK4, LcCS1, LcCS2, LcSAT, LcMDH1 and LcMDH2) was also significantly down-regulated. In contrast, the level of ATP, an important metabolite in the oxidative phosphorylation pathway, was elevated in parallel with both higher activity of H⁺-ATPase and the increased expression level of LcH⁺-ATPase1. In conclusion, our findings suggest that carbon starvation can induce fruitlet abscission in litchi probably by energy depletion that mediated through both the suppression of the glycolysis pathway and TCA cycle and the enhancement of the oxidative phosphorylation pathway. Full article

(This article belongs to the Collection Advances in Tropical Fruit Cultivation and Breeding)

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12 pages, 26913 KiB

Open AccessEditor’s ChoiceArticle

Colloidal Silver Hydrogen Peroxide: New Generation Molecule for Management of Phytopathogens

by Hosapura Shekhararaju Mahesha, Jayasuvarnapura Umapathi Vinay, Medikeripura Rekhyanaik Ravikumar, Suryanarayana Visweswarashastry, Manikyanahalli Chandrashekhara Keerthi, Hanamant Mudakappa Halli, Shadi Shokralla, Tarek K. Zin El-Abedin, Eman A. Mahmoud and Hosam O. Elansary

Horticulturae 2021, 7(12), 573; https://doi.org/10.3390/horticulturae7120573 - 13 Dec 2021

Cited by 5 | Viewed by 9387

Abstract

Plant pathogenic fungi and bacteria are a significant threat to global commercial crop production resulting in increased cost of production, reduced crop establishment and productivity. An effort was made to study the antimicrobial activity of silver hydrogen peroxide (SHP) against selected plant pathogenic [...] Read more.

Plant pathogenic fungi and bacteria are a significant threat to global commercial crop production resulting in increased cost of production, reduced crop establishment and productivity. An effort was made to study the antimicrobial activity of silver hydrogen peroxide (SHP) against selected plant pathogenic fungi and bacteria under in vitro conditions. Higher antibacterial activity of SHP was observed against Xanthomonas axonopodis pv. citri (Xac; 39.67 mm), Xanthomonas citri pv. punicae (Xap; 39.00 mm), and Ralstonia solanacearum (Rs; 36.67 mm) at 500 ppm concentration. SHP was superior to streptocycline (500 ppm) against Xac (25.33 mm) and Xcp (22.67 mm) at 100 ppm. The soil-borne fungi viz., Pythium aphanidermatum and Fusarium solani failed to initiate mycelium growth on PDA at the concentration of 5000 ppm and above. The average size of SHP particles was 462 nm in diameter, and 73.40% of particles had the size of 378 nm, which reflects the particles present in SHP solution in the form of colloids. The effective doses (100–5000 ppm) did not show any phytotoxicity symptoms in plants, while leaf necrosis was noticed at 10,000 ppm after four days of application. SHP (≤5000 ppm) can be used to effectively manage both fungal and bacterial plant pathogens by a single application. Further field studies need to be conducted for validation and commercial use of SHP. Full article

(This article belongs to the Special Issue Plant Disease Management: Latest Advances and Prospects)

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