Horticulturae

17 pages, 4294 KiB

Open AccessArticle

Evaluation of Effect of Brassinolide in Brassica juncea Leaves under Drought Stress in Field Conditions

by Naveen Naveen, Nisha Kumari, Ram Avtar, Minakshi Jattan, Sushil Ahlawat, Babita Rani, Kamla Malik, Anubhuti Sharma and Manjeet Singh

Horticulturae 2021, 7(11), 514; https://doi.org/10.3390/horticulturae7110514 - 22 Nov 2021

Cited by 8 | Viewed by 2490

Abstract

Drought stress is considered to be a major factor responsible for reduced agricultural productivity, because it is often linked to other major abiotic stresses, such as salinity and heat stress. Understanding drought-tolerance mechanisms is important for crop improvement. Moreover, under drought conditions, it [...] Read more.

Drought stress is considered to be a major factor responsible for reduced agricultural productivity, because it is often linked to other major abiotic stresses, such as salinity and heat stress. Understanding drought-tolerance mechanisms is important for crop improvement. Moreover, under drought conditions, it is possible that growth regulators are able to protect the plants. Brassinosteroids not only play a regulatory role in plant growth, but also organize defense mechanisms against various tresses. This study aimed to evaluate the effect of brassinolide on physio-biochemical amendment in two contrasting cultivars (drought-tolerant RH 725, and drought-sensitive RH 749) of Brassica juncea under drought stress. Two foliar sprayings with brassinolide (10 and 20 mg/L) were carried out in both cultivars (RH 725 and RH 749) at two stages—i.e., flower initiation, and 50% flowering—under stress conditions. The results clearly revealed that the activities of antioxidative enzymes and non-enzymatic antioxidants (carotenoids, ascorbic acid, and proline) increased significantly in RH 725 at 50% flowering, whereas 20 mg/L of brassinolide showed the most promising response. The different oxidative stress indicators (i.e., hydrogen peroxide, malondialdehyde, and electrolyte leakage) decreased to a significant extent at 20 mg/L of brassinolide spray in RH 725 at 50% flowering. This study indicates that brassinolide intensifies the physio-biochemical attributes by improving the antioxidant system and photosynthetic efficiency in RH 725 at 50% flowering. It is assumed that enhanced production of proline, improvement of the antioxidant system, and reduction in the amount of stress indicators impart strength to the plants to combat the stress conditions. Full article

(This article belongs to the Special Issue Advances in Brassica Crops Genomics and Breeding)

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18 pages, 1489 KiB

Open AccessReview

The Applications of Molecular Hydrogen in Horticulture

by Longna Li, Yan Zeng, Xu Cheng and Wenbiao Shen

Horticulturae 2021, 7(11), 513; https://doi.org/10.3390/horticulturae7110513 - 22 Nov 2021

Cited by 10 | Viewed by 3535

Abstract

Improvements in the growth, yield, and quality of horticultural crops require the development of simply integrated, cost-efficient, and eco-friendly solutions. Hydrogen gas (H₂) has been observed to have fertilization effects on soils by influencing rhizospheric microorganisms, resulting in improvements in crop [...] Read more.

Improvements in the growth, yield, and quality of horticultural crops require the development of simply integrated, cost-efficient, and eco-friendly solutions. Hydrogen gas (H₂) has been observed to have fertilization effects on soils by influencing rhizospheric microorganisms, resulting in improvements in crop yield and quality. Ample studies have shown that H₂ has positive effects on horticultural crops, such as promoting root development, enhancing tolerance against abiotic and biotic stress, prolonging storage life, and improving postharvest quality of fruits, vegetables and cut flowers. In this review, we aim to evaluate the feasibility of molecular hydrogen application in horticulture and the strategies for its application, including H₂ delivery methods, treatment timing, and the concentration of H₂ applied. The discussion will be accompanied by outlining the effects of H₂ and the likely mechanisms of its efficacy. In short, the application of H₂ may provide novel opportunities for simple and cost efficient improvements of horticultural production in terms of increased yield and product quality but with low carbon dioxide emissions. Full article

(This article belongs to the Special Issue Uses of Hydrogen Gas in Horticulture)

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10 pages, 1360 KiB

Open AccessArticle

Suitability of On-Farm Green Compost for the Production of Baby Leaf Species

by Enrica De Falco, Antonella Vitti, Giuseppe Celano and Domenico Ronga

Horticulturae 2021, 7(11), 512; https://doi.org/10.3390/horticulturae7110512 - 20 Nov 2021

Cited by 6 | Viewed by 2194

Abstract

This study evaluated, for the first time, the suitability of on-farm green compost (GC) from the fourth range sector for the production, in a controlled environment, of six baby leaf species (radish, lettuce, rocket, chard, sorrel and dill), characterized by short cultivation cycles. [...] Read more.

This study evaluated, for the first time, the suitability of on-farm green compost (GC) from the fourth range sector for the production, in a controlled environment, of six baby leaf species (radish, lettuce, rocket, chard, sorrel and dill), characterized by short cultivation cycles. The pH and electrical conductivity of potting soil-compost mixtures were affected by the different amounts of GC added to the potting soil. Germination tests on Lactuca sativa seeds indicated no phytotoxic effects when GC was used to prepare aqueous extracts diluted at 50% and 25% (v/v). In the pot experiment, GC was used at four different dosages in the growing medium, inducing different impacts on growth parameters, depending on the species and applied dose. The greatest plant growth responses were determined by using less than 3.5 g of GC in 100 g of potting soil. Significant positive correlations between the dry weights of root and shoot (r = 0.77 **), seedling height (r = 0.51 **) and the number of true leaves number (r = 0.56 **) confirmed the close relationship between the root system biomass and the growth parameters of aboveground organs. The study highlights that on-farm green compost, used as partial growing substrate, provides a good opportunity to obtain baby leaf species with well-developed root systems. Full article

(This article belongs to the Section Vegetable Production Systems)

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11 pages, 6182 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Somatic Embryogenesis in Vitis for Genome Editing: Optimization of Protocols for Recalcitrant Genotypes

by Lucia Rosaria Forleo, Margherita D’Amico, Teodora Basile, Antonio Domenico Marsico, Maria Francesca Cardone, Flavia Angela Maria Maggiolini, Riccardo Velasco and Carlo Bergamini

Horticulturae 2021, 7(11), 511; https://doi.org/10.3390/horticulturae7110511 - 19 Nov 2021

Cited by 5 | Viewed by 2024

Abstract

New Plant Breeding Techniques (NPBTs) protocols have been developed to produce new grape varieties with improved quantitative and qualitative characteristics. Reliable transformation protocols for grapes are based on the generation/induction of embryogenic callus cells that are then transformed. Varieties such as Italia have [...] Read more.

New Plant Breeding Techniques (NPBTs) protocols have been developed to produce new grape varieties with improved quantitative and qualitative characteristics. Reliable transformation protocols for grapes are based on the generation/induction of embryogenic callus cells that are then transformed. Varieties such as Italia have proven to be very recalcitrant to regeneration via somatic embryogenesis. In this work, the development of a protocol for improved production of embryogenic calluses is described. Two sterilization protocols were tested: (a) a lower active chlorine concentration for a longer time (LS); and (b) a higher chlorine concentration for a shorter time (HS), in combination with the absence or presence of citric acid in the growing substrate in the first growth media. The embryogenic calluses formation in Chardonnay, a cv. with a high embryogenic response, was significantly higher in presence of citric acid in the initial growing substrate regardless of the sterilization protocol. In Aglianico, a cv. with a lower embryogenic response, no significant differences were observed. Instead, in a recalcitrant cv. as Italia, we obtained a 13-fold increase in embryogenic calluses formation performing sterilization of flowers with the HS protocol compared to LS. Full article

(This article belongs to the Collection Application of Tissue Culture to Horticulture)

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17 pages, 2537 KiB

Open AccessArticle

Mitigation of Drought Damages by Exogenous Chitosan and Yeast Extract with Modulating the Photosynthetic Pigments, Antioxidant Defense System and Improving the Productivity of Garlic Plants

by Khaled Abdelaal, Kotb A. Attia, Gniewko Niedbała, Tomasz Wojciechowski, Yaser Hafez, Salman Alamery, Talal K. Alateeq and Sally A. Arafa

Horticulturae 2021, 7(11), 510; https://doi.org/10.3390/horticulturae7110510 - 19 Nov 2021

Cited by 34 | Viewed by 2793

Abstract

Garlic is an important vegetable in terms of its economic value and also as a medicinal plant. In this study, chitosan (300 mM) and yeast extract (8 g/L) were used individually or in combination to improve the yields of garlic plants under drought [...] Read more.

Garlic is an important vegetable in terms of its economic value and also as a medicinal plant. In this study, chitosan (300 mM) and yeast extract (8 g/L) were used individually or in combination to improve the yields of garlic plants under drought conditions (i.e., 75% and 50% of the water they would normally receive from irrigation) for two seasons. Significant decreases in numbers of leaves per plant and plant height, plant dry weight, relative water content, and chlorophyll a and b concentrations were found in stressed garlic plants in both seasons. The greatest reductions in these characters were recorded in plants that received only 50% of the normal irrigation in both seasons. Levels of hydrogen peroxide, products of lipid peroxidation such as malondialdehyde, and superoxide, as well as percentages of electrolyte leakage, were elevated considerably and were signals of oxidative damage. The application of the yeast extract (8 g/L) or chitosan (300 mM) individually or in combination led to a remarkable increase in the most studied characters of the stressed garlic plants. The combination of yeast extract (8 g/L) plus chitosan (300 mM) led to increase plant height (44%), ascorbic acid levels (30.2%), and relative water content (36.8%), as well as the chlorophyll a (50.7%) and b concentrations (79%), regulated the proline content and levels of antioxidant enzymes in stressed garlic plants that received 75% of the normal irrigation, and this decreased the signs of oxidative stress (i.e., percentage of electrolyte leakage and levels of malondialdehyde, hydrogen peroxide, and superoxide). Full article

(This article belongs to the Special Issue Plant Physiology under Abiotic Stresses)

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19 pages, 2888 KiB

Open AccessEditor’s ChoiceArticle

Impact of Elevated CO₂ and Temperature on Growth, Development and Nutrient Uptake of Tomato

by Tejaswini C. Rangaswamy, Shankarappa Sridhara, Konapura Nagaraja Manoj, Pradeep Gopakkali, Nandini Ramesh, Shadi Shokralla, Tarek K. Zin El-Abedin, Khalid F. Almutairi and Hosam O. Elansary

Horticulturae 2021, 7(11), 509; https://doi.org/10.3390/horticulturae7110509 - 19 Nov 2021

Cited by 6 | Viewed by 2603

Abstract

Elevated carbon dioxide (EC) can increase the growth and development of different C₃ fruit crops, which may further increase the nutrient demand by the accumulated biomass. In this context, the current investigation was conceptualized to evaluate the growth performance and nutrient uptake [...] Read more.

Elevated carbon dioxide (EC) can increase the growth and development of different C₃ fruit crops, which may further increase the nutrient demand by the accumulated biomass. In this context, the current investigation was conceptualized to evaluate the growth performance and nutrient uptake by tomato plants under elevated CO₂ (EC₇₀₀ and EC₅₅₀ ppm) and temperature (+2 °C) in comparison to ambient conditions. Significant improvement in the growth indicating parameters like leaf area, leaf area index, leaf area duration and crop growth rate were measured at EC₇₀₀ and EC₅₅₀ at different stages of crop growth. Further, broader and thicker leaves of plants under EC₇₀₀ and EC₅₅₀ have intercepted higher radiation by almost 11% more than open field plants. Conversely, elevated temperature (+2 °C) had negative influence on crop growth and intercepted almost 7% lower radiation over plants under ambient conditions. Interestingly, earliness of phenophases viz., branch initiation (3.0 days), flower initiation (4.14 days), fruit initiation (4.07 days) and fruit maturation (7.60 days) were observed at EC₇₀₀ + 2 °C, but it was statistically on par with EC₇₀₀ and EC₅₅₀ + 2 °C. Irrespective of the plant parts and growth stages, plants under EC₇₀₀ and EC₅₅₀ have showed significantly higher nutrient uptake due to higher root biomass. At EC₇₀₀, the tune of increase in total nitrogen, phosphorus and potassium uptake was almost 134%, 126% and 135%, respectively compared to open field crop. This indicates higher nutrient demand by the crop under elevated CO₂ levels because of higher dry matter accumulation and radiation interception. Thus, nutrient application is needed to be monitored at different growth stages as per the crop needs. Full article

(This article belongs to the Special Issue Nutrient Use Efficiency under Optimal and Stressful Conditions of Horticulture Plants)

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16 pages, 7696 KiB

Open AccessArticle

Flowering Biology of Rhododendron pulchrum

by Jie Qiu, Chao Gao, Hongli Wei, Biao Wang, Yang Hu, Zhiyan Guo, Li Long, Lu Yang and Huie Li

Horticulturae 2021, 7(11), 508; https://doi.org/10.3390/horticulturae7110508 - 18 Nov 2021

Cited by 3 | Viewed by 2485

Abstract

To study the flowering biology of Rhododendron pulchrum, we used scanning electron microscopy (SEM) and paraffin sectioning to observe the microstructures of its floral organs, a methyl thiazolyl tetrazolium (MTT) colorimetric assay to detect pollen viability in different periods, continuous observations to study [...] Read more.

To study the flowering biology of Rhododendron pulchrum, we used scanning electron microscopy (SEM) and paraffin sectioning to observe the microstructures of its floral organs, a methyl thiazolyl tetrazolium (MTT) colorimetric assay to detect pollen viability in different periods, continuous observations to study flowering phenology, and artificial pollination and a benzidine-hydrogen peroxide method to determine stigma receptivity. R. pulchrum exhibited a centralized flowering phenology. The protogynous stigmas of R. pulchrum were able to receive pollen before flowering. The pollen grains of R. pulchrum fused into tetrads, the average ratio of the polar axis length to the equatorial axis length (P/E) was 1.05, and the pollen viability was highest in the initial flowering period, reaching 88.98%. The pollen/ovule (P/O) ratio was 266–328, and the outcrossing index (OCI) was 4; the vitality of R. pulchrum pollen remained high in the initial flowering and blooming periods. Compared with the lifespan of a single flower, pollen vitality remained high for most of the experimental period, thereby improving male fitness. The P/O ratio suggests that R. pulchrum may have a facultative outcrossing breeding system. The OCI estimation suggests that R. pulchrum is partially self-compatible, most likely requiring pollinators to complete pollination. Full article

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16 pages, 4135 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Effects of Different Fertilization Practices in Combination with the Use of PGPR on the Sugar and Amino Acid Content of Asparagus officinalis

by Nikolaos Xekarfotakis, Theocharis Chatzistathis, Magkdi Mola, Triantafyllia Demirtzoglou and Nikolaos Monokrousos

Horticulturae 2021, 7(11), 507; https://doi.org/10.3390/horticulturae7110507 - 18 Nov 2021

Cited by 5 | Viewed by 2290

Abstract

The present study examined the effects of different nitrogen (NH₄NO₃) and potassium (KNO₃) fertilization levels in combination with a nitrogen-fixing, plant growth-promoting rhizobacteria (PGPR) inoculation on the carbohydrate (CHO), amino acid content, and nutrient concentrations (N, P, [...] Read more.

The present study examined the effects of different nitrogen (NH₄NO₃) and potassium (KNO₃) fertilization levels in combination with a nitrogen-fixing, plant growth-promoting rhizobacteria (PGPR) inoculation on the carbohydrate (CHO), amino acid content, and nutrient concentrations (N, P, K) in the spears and the root system of asparagus plants. No significant differences were indicated between the different fertilization treatments regarding N, P, and K in the leaves and roots of asparagus. The inoculation of the asparagus fields with PGPR, no matter the type of the inorganic fertilizer, resulted in increased CHO and amino acid content of the foliage and roots of asparagus. The highest CHO content and amino acid content were recorded in the treatment that combined PGPR inoculation along with KNO₃ fertilizer, indicating that higher K applications acted synergistically with the added PGPR. Full article

(This article belongs to the Special Issue Nutrient Use Efficiency under Optimal and Stressful Conditions of Horticulture Plants)

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18 pages, 1807 KiB

Open AccessArticle

Improving Shelf Life, Maintaining Quality, and Delaying Microbial Growth of Broccoli in Supply Chain Using Commercial Vacuum Cooling and Package Icing

by Pimonphat Dirapan, Danai Boonyakiat and Pichaya Poonlarp

Horticulturae 2021, 7(11), 506; https://doi.org/10.3390/horticulturae7110506 - 18 Nov 2021

Cited by 9 | Viewed by 3612

Abstract

Poor and inconsistent quality is a major barrier to increasing produce consumption, and the lack of shelf-life after purchase is the quality issue at retail displays of produce. This research aimed to investigate and identify cooling techniques, namely vacuum cooling and package icing [...] Read more.

Poor and inconsistent quality is a major barrier to increasing produce consumption, and the lack of shelf-life after purchase is the quality issue at retail displays of produce. This research aimed to investigate and identify cooling techniques, namely vacuum cooling and package icing used in supply chains, and any resulting extension of broccoli shelf-life, maintenance of physicochemical quality, and delay in microbial growth at retail stores. Broccoli (Brassica oleracea var. italica cv. Montop) sustainably grown in the highlands of northern Thailand, Chiang Mai Province, under the Royal Project Foundation was experimented on vacuum cooling and package icing were selected to precool broccoli to 4 ± 1 °C. The effects of vacuum cooling using a final pressure of 0.6 kPa for 30 min and package icing using liner Styrofoam boxes (the best ratio of broccoli to crushed ice was 1:1 w/w) on physicochemical qualities, microbial growth, and shelf-life in simulated refrigerated retail displays were examined. The results illustrated that the shelf-life and quality of broccoli could be extended using both vacuum cooling and package icing. Both precooling techniques inhibited the yellowing of florets, provided high sensory scores, delayed microbial growth, and could be able to extend the shelf-life of broccoli. However, package icing offered greater potential for maintaining quality, especially retaining bioactive compounds, and extending shelf-life, thereby increasing the produce market window from 5 to 12 days at 8 ± 1 °C with 85% RH. Therefore, package icing was recommended in the supply chain for fresh broccoli cv. Montop grown in northern Thailand. Full article

(This article belongs to the Topic New Trends in Agri-Food Sector: Environmental, Economic and Social Perspectives)

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11 pages, 2953 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Urban Double-Crop: Can Fall Vegetables and a Warm-Season Lawn Co-Exist?

by Ellen M. Bauske, Sheri Dorn, Freddie Clinton Waltz, Jr. and Lauren Garcia Chance

Horticulturae 2021, 7(11), 505; https://doi.org/10.3390/horticulturae7110505 - 18 Nov 2021

Viewed by 1657

Abstract

A gardening methodology using double-cropped cool-season vegetables and warm-season turfgrass, thereby capitalizing on the ideal growing season for each, was developed in field trials and tested in volunteers’ landscapes. Broccoli (Brassica oleracea), lettuce (Lactuca sativa), and Swiss chard ( [...] Read more.

A gardening methodology using double-cropped cool-season vegetables and warm-season turfgrass, thereby capitalizing on the ideal growing season for each, was developed in field trials and tested in volunteers’ landscapes. Broccoli (Brassica oleracea), lettuce (Lactuca sativa), and Swiss chard (Beta vulgaris subsp. Cicla) were planted into an established hybrid bermudagrass lawn (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy ‘Tifsport’) in September. The vegetables were planted into tilled strips, 5 cm × 10 cm holes and 10 cm × 10 cm holes in the turf. All treatments produced harvestable yield, though the yield of vegetables planted in the tilled treatments and larger holes was greater than in smaller holes. Efforts to reduce turfgrass competition with vegetables by the application of glyphosate or the use of the Veggie Lawn Pod (an easily installed plastic cover on the lawn) did not increase yield. Tilled treatments left depressions that discouraged spring turfgrass recovery. The double-crop was tested by seven volunteers on their lawns. Though lawn-planted vegetables did not produce as much yield as those planted in the volunteers’ gardens, the volunteers were enthusiastic about this methodology. The volunteers reported that lawn vegetables were more difficult to plant but not more difficult to maintain, and they were easier to harvest than vegetables in their gardens. All volunteers reported satisfactory recovery of their lawns in the spring. Full article

(This article belongs to the Special Issue Consumer Horticulture Advancement)

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11 pages, 1292 KiB

Open AccessArticle

A Potential Application of Endophytic Bacteria in Strawberry Production

by Chuansheng Mei, B. Sajeewa Amaradasa, Robert L. Chretien, Danyang Liu, George Snead, Jayesh B. Samtani and Scott Lowman

Horticulturae 2021, 7(11), 504; https://doi.org/10.3390/horticulturae7110504 - 18 Nov 2021

Cited by 9 | Viewed by 2825

Abstract

Endophytic bacteria could be used as a tool to promote plant growth, enhance abiotic stress tolerance, and inhibit plant pathogen growth. More than 100 bacteria, previously tested to have biocontrol activity against fungal pathogens from our lab, were chosen for pathogen inhibition in [...] Read more.

Endophytic bacteria could be used as a tool to promote plant growth, enhance abiotic stress tolerance, and inhibit plant pathogen growth. More than 100 bacteria, previously tested to have biocontrol activity against fungal pathogens from our lab, were chosen for pathogen inhibition in vitro with antibiosis assays against strawberry specific pathogens. Three potential endophytic bacteria were tested in the greenhouse for disease reduction and growth performance. Finally, field trials were conducted for fruit yield production. Our results showed that three endophytic bacteria significantly inhibited the growth of the strawberry pathogen Colletotrichum gloeosporioides from antibiosis assays and were identified as Bacillus velezensis strains IALR308, IALR585, and IALR619. Inoculation of these bacteria significantly reduced strawberry disease in greenhouse conditions with pathogen infection. Field trials showed that IALR619 has potential to influence marketable fruit yield when strawberry plants were inoculated twice over the growing season. All three bacteria had the ability to produce auxin and to solubilize phosphate. The antibiotics surfactin and iturin were also detected in IALR585 and IALR619. In conclusion, Bacillus velezensis IALR619 has potential inhibition of strawberry pathogen growth in the greenhouse and possible ability to increase marketable fruit yield in the field. Full article

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12 pages, 1756 KiB

Open AccessArticle

Water Use Efficiency and Nutritional Status of a New Grapevine Rootstock Selection

by Davide Bianchi and Lucio Brancadoro

Horticulturae 2021, 7(11), 503; https://doi.org/10.3390/horticulturae7110503 - 18 Nov 2021

Cited by 6 | Viewed by 2035

Abstract

The production and quality of grapes are determined by the hydric and nutritional status of the vine. In modern viticulture, the interface between grapevine and soil is represented by the rootstock, which modulates the uptake of water and nutrients. Thus, selection of new [...] Read more.

The production and quality of grapes are determined by the hydric and nutritional status of the vine. In modern viticulture, the interface between grapevine and soil is represented by the rootstock, which modulates the uptake of water and nutrients. Thus, selection of new rootstocks for abiotic stress tolerance represents an adaptation strategy for viticulture to the new environmental conditions imposed by climate change. The aim of this work is to evaluate the water-use efficiency (WUE) and the nutritional status of a selection of 30 new rootstock genotypes, originating from several breeding programs. WUE and gas exchange were measured for each genotype in two environments characterized by different water availability, and the levels of N, P, K, Mg, Ca, Na, Fe, Mn, and Zn in the leaf blades were determined during the phenological stages of flowering and ripening. Water availability was different in the two environments, affecting gas exchange, with mean values of carbon assimilation of 10.43 ± 0.32 and 3.84 ± 0.34 µmol CO₂ m⁻² s⁻¹, respectively. Genotypes were classified according to their water stress tolerance, vigor, and affinity for macronutrients and micronutrients. A total of 14 genotypes showed tolerance to water stress, and 10 of them reported high vigor and carbon assimilation. Furthermore, the majority of water-stress-tolerant genotypes had greater affinity for Mg than for K. In further studies, the most promising rootstocks will be evaluated in grafting combination with Vitis vinifera. Full article

(This article belongs to the Special Issue Rootstock Genetics and Improvement in Breeding)

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17 pages, 5189 KiB

Open AccessArticle

Comparative Transcriptomic Analyses Provide Insights into the Enzymatic Browning Mechanism of Fresh-Cut Sand Pear Fruit

by Jing Fan, Wei Du, Qi-Liang Chen, Jing-Guo Zhang, Xiao-Ping Yang, Syed Bilal Hussain and Hong-Ju Hu

Horticulturae 2021, 7(11), 502; https://doi.org/10.3390/horticulturae7110502 - 16 Nov 2021

Cited by 8 | Viewed by 3176

Abstract

Pear (Pyrus spp.) is one of the most commonly consumed temperate fruits, having considerable economic and health importance. Fresh-cut or processed pear fruits are prone to browning because of the abundant phenolic compounds; however, little is known about the molecular mechanisms underlying [...] Read more.

Pear (Pyrus spp.) is one of the most commonly consumed temperate fruits, having considerable economic and health importance. Fresh-cut or processed pear fruits are prone to browning because of the abundant phenolic compounds; however, little is known about the molecular mechanisms underlying enzymatic browning of fresh-cut sand pear fruit. In this study, fruits of two sand pear genotypes (low browning cultivar ‘Eli No.2′ and high browning cultivar ‘Weiningdahuangli’) were used to analyze the molecular mechanism of enzymatic browning by SMRT-seq and RNA-seq. The results generated 69,122 consensus isoforms, 21,336 new transcripts, 7105 alternative splicing events, and 254 long non-coding RNAs (lncRNAs). Furthermore, five genes related to enzymatic browning were predicted to be targets of six lncRNAs, and 9930 differentially expressed genes (DEGs) were identified between two different flesh browning cultivars. Meanwhile, most DEGs (e.g., PAL, 4CL, CAD, CCR, CHS, and LAR) involved in the phenylpropanoid biosynthesis pathway were up-regulated, and the expression of PPO and POD were highly expressed in the high-browning cultivar. Interestingly, the transcript level of PbrPPO4 (Pbr000321.4) was significantly higher than other PPO and POD genes, and a high level of total polyphenol and PPO activity were observed in the high browning cultivar. We found that the expression of lncRNA PB.156.1 was significantly positively correlated with the target gene PbrPPO4 (Pbr000321.4). The results suggest that PbrPPO4 might act as a major contributor and a key enzyme encoding gene in regulating fresh-cut sand pear fruit enzymatic browning; the expression of PbrPPO4 was probably regulated by lncRNA PB.156.1. Altogether, the transcriptomic and physiological analyses expand the knowledge of sand pear flesh enzymatic browning at the molecular level and provide a foundation for germplasm resources for molecular breeding of high polyphenol and low browning cultivars in sand pears. Full article

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

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16 pages, 3771 KiB

Open AccessArticle

Key Proteins and Metabolic Pathways Involved in 24-Epibrasionlide Improving Drought Tolerance of Rhododendron delavayi Franch

by Yan-Fei Cai, Lu Zhang, Lv-Chun Peng, Shi-Feng Li, Jie Song, Wei-Jia Xie and Ji-Hua Wang

Horticulturae 2021, 7(11), 501; https://doi.org/10.3390/horticulturae7110501 - 16 Nov 2021

Cited by 2 | Viewed by 1715

Abstract

Rhododendron delavayi Franch. is a famous ornamental plant. However, seasonal drought caused by a monsoon climate seriously limits its growth and flowering performance in urban gardens. Our previous study has found that brassinosteroids (BRs) can improve the tolerance of R. delavayi to drought [...] Read more.

Rhododendron delavayi Franch. is a famous ornamental plant. However, seasonal drought caused by a monsoon climate seriously limits its growth and flowering performance in urban gardens. Our previous study has found that brassinosteroids (BRs) can improve the tolerance of R. delavayi to drought stress. Here, we employed a data-independent acquisition (DIA) approach to compare the protein expression profiles under drought treatment (D) and pre-treatment with BR before drought treatment (BR). With an increase in drought stress, the net photosynthetic rate, stomatal conductance, and transpiration rate in the BR treatment showed more stable changes that were significantly higher than those in the D treatment. However, the contents of malondialdehyde, soluble sugar, soluble protein, and the activity of superoxide dismutase (SOD), peroxidase, and catalase showed opposite trends. The pre-treatment with BR alleviated the negative effect of drought stress on the photosynthetic performance of R. delavayi. A total of 3453 differentially expressed proteins (DEPs) were identified, and 683 DEPs were significantly expressed in the D and BR treatments. The DEPs uniquely expressed in the BR treatment participated in the pathways of “ribosome”, “ether lipid metabolism”, “photosynthesis”, and “oxidative phosphorylation”. The improvement effect of the BR treatment on the drought tolerance of R. delavayi was mainly attributed to improved photosynthesis by alleviating stomatal closure and oxidative stress, maintaining the integrity and stability of the ribosomal complex to mediate protein synthesis and the balance between energy metabolism and carbon metabolism. Our study presents a comprehensive understanding of the key proteins and metabolic pathways related to the response of R. delavayi to drought and will contribute to the breeding of drought-tolerant rhododendrons. Full article

(This article belongs to the Topic Physiological and Molecular Characterization of Crop Tolerance to Abiotic Stresses)

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17 pages, 1923 KiB

Open AccessArticle

The Effect of Microbial Fertilizer on the Growth, Rhizospheric Environment and Medicinal Quality of Fritillaria taipaiensis

by Nong Zhou, Maojun Mu, Min Yang, You Zhou and Mingguo Ma

Horticulturae 2021, 7(11), 500; https://doi.org/10.3390/horticulturae7110500 - 15 Nov 2021

Cited by 6 | Viewed by 2043

Abstract

Fritillaria taipaiensis is a valuable traditional Chinese medicinal plant affected by germplasm degradation during cultivation. To find a suitable solution for this problem, F. taipaiensis was inoculated with exogenous arbuscular mycorrhiza (AM) fungi, potassium-solubilizing bacteria, and phosphorus-solubilizing bacteria in pot experiments. The effects [...] Read more.

Fritillaria taipaiensis is a valuable traditional Chinese medicinal plant affected by germplasm degradation during cultivation. To find a suitable solution for this problem, F. taipaiensis was inoculated with exogenous arbuscular mycorrhiza (AM) fungi, potassium-solubilizing bacteria, and phosphorus-solubilizing bacteria in pot experiments. The effects of inoculation on the AM colonization, photosynthetic pigment, and superoxide dismutase contents, rhizospheric enzyme activities, alkaloid, and nucleotide content of F. taipaiensis were studied. The results showed that the inoculation increased mycorrhizal infection intensity of F. taipaiensis. Compared to the control group, the photosynthetic pigment contents in the leaf of the inoculation groups were increased; the content of soluble protein, the activities of the superoxide dismutase, catalase, and peroxidase in leaves were all significantly increased, and the content of malondialdehyde was decreased. The microbial inoculum also increased the content of active ingredients in F. taipaiensis bulbs and increased the enzyme activities, total microorganism number, bacteria/fungi, and actinomycetes/fungi ratios in the rhizosphere. To sum up, microbial fertilizer can significantly improve the rhizospheric environment and medicinal quality of F. taipaiensis. This research provides a theoretical basis and experimental evidence for the sustainable development of an F. taipaiensis industry. Full article

(This article belongs to the Special Issue Mycorrhizal Roles in Horticultural Plants)

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19 pages, 6427 KiB

Open AccessEditor’s ChoiceArticle

Postharvest Treatment of ‘Florida Prince’ Peaches with a Calcium Nanoparticle–Ascorbic Acid Mixture during Cold Storage and Its Effect on Antioxidant Enzyme Activities

by Lo’ay A. A., Hamed Ismail and Hazem S. Kassem

Horticulturae 2021, 7(11), 499; https://doi.org/10.3390/horticulturae7110499 - 15 Nov 2021

Cited by 7 | Viewed by 2267

Abstract

Chilling injury (CI) is a physiological disorder resulting from low storage temperatures that affects the fruit quality and marketing of the ‘Florida Prince’ peach. In this study, the exogenous application of a mixture of calcium nanoparticles (CaNPs) and ascorbic acid was found to [...] Read more.

Chilling injury (CI) is a physiological disorder resulting from low storage temperatures that affects the fruit quality and marketing of the ‘Florida Prince’ peach. In this study, the exogenous application of a mixture of calcium nanoparticles (CaNPs) and ascorbic acid was found to significantly alleviate the symptoms of CI in peaches during cold storage. Fruits were treated with CaNPs plus different concentrations of ascorbic acid (AA; 0, 3, 6, and 9 mM). Peaches were immersed in CaNP–AA for 15 min before being stored at 4 ± 1 °C and 95 ± 1% RH for 30 days. We observed that the 9 mM CaNP–AA treatment lowered the values for the CI index, ion leakage, and malondialdehyde (MDA) content and increased antioxidant enzyme activities (AEAs), such as for ascorbate oxidase (APX), catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR). Furthermore, the treatment reduced the accumulation of both H₂O₂ and O₂^•− and increased the level of DPPH reduction throughout the duration of cold storage. Our results suggest that 9 mM CaNP–AA treatment suppresses the incidence of CI in peach fruit throughout cold storage, possibly because 9 mM CaNP–AA is at least partly involved in enhancing the antioxidant system via its effect on antioxidant substances. The results indicate that applying the 9 mM CaNP–AA treatment afforded peaches with enhanced tolerance against cold storage stress. Full article

(This article belongs to the Collection Postharvest Handling of Horticultural Crops)

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19 pages, 5550 KiB

Open AccessArticle

On the Biochemical and Physiological Responses of ‘Crimson Seedless’ Grapes Coated with an Edible Composite of Pectin, Polyphenylene Alcohol, and Salicylic Acid

by A. A. Lo’ay, M. M. Rabie, Haifa A. S. Alhaithloul, Suliman M. S. Alghanem, Aly M. Ibrahim, Mohamed A. Abdein and Zinab A. Abdelgawad

Horticulturae 2021, 7(11), 498; https://doi.org/10.3390/horticulturae7110498 - 15 Nov 2021

Cited by 5 | Viewed by 2565

Abstract

The ‘Crimson seedless’ grape encountered several difficulties during shelf life, including weight loss, rachis browning, and berry shattering. The effect of exogenous pectin (PE) and polyphenol alcohol (PVA) with supporting salicylic acid (SA) at different concentrations (0, 1, and 2 mM) was applied. [...] Read more.

The ‘Crimson seedless’ grape encountered several difficulties during shelf life, including weight loss, rachis browning, and berry shattering. The effect of exogenous pectin (PE) and polyphenol alcohol (PVA) with supporting salicylic acid (SA) at different concentrations (0, 1, and 2 mM) was applied. The coating was applied to bunches for 5 min and stored at room temperature (26 ± 1 °C and RH 65 ± 3%) for 4 days. In this study, postharvest application of PE + PVA-SA can significantly reduce the cell wall degradation enzyme activities of ‘Crimson seedless’ grape during shelf life. ‘Crimson seedless’ bunches, treated with PE + PVA-SA _{2 mmol L⁻¹}, had a lowered rachis browning index (RB index), weight loss (WL%), and berry shattering percentage (BS%) and preserved berry color hue angle (h^o) compared to untreated bunches during shelf-life duration. Moreover, the PE + PVA-SA _{2 mM} improved berry firmness (BF) and removal force (BRF). It also improved the soluble solid content (SSC%), titratable acidity (TA%), and SSC: TA-ratio, for assessing berry maturity. The cellular metabolism enzyme activities (CMEAs) of the cell wall such as polygalacturonase (PG), cellulase (CEL), xylanase (XYL), and pectinase (PT) were minimized by applying PE + PVA-SA _{2 mM} coatings throughout storage duration. The accumulation of malondialdehyde (MDA) and cell wall damage, as well as the electrolyte leakage percentage (EL%), was reduced. PE + PVA-SA _{2 mM} maintained DPPH radical quenching activities and minimized O₂⁻ and H₂O₂ production rates. Collectively, these findings suggest that PE + PVA with the presence of SA as a coating treatment preserved ‘Crimson seedless’ bunches during shelf life. PE + PVA-SA _{2 mM} might be at least partially ascribed to the enhancement of bunches’ quality traits as well as inhibiting cell wall damage during the shelf-life period. Full article

(This article belongs to the Special Issue Alternatives to Chemicals in Fruits and Vegetables Production and Storage)

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11 pages, 5258 KiB

Open AccessEditor’s ChoiceArticle

Somatic Embryogenesis and Indirect In Vitro Plant Regeneration in Amorphophallus konjac K. Koch by One-Step Seedling Formation

by Dandan Li, Mohammad Aqa Mohammadi, Yuan Qin and Zongshen Zhang

Horticulturae 2021, 7(11), 497; https://doi.org/10.3390/horticulturae7110497 - 15 Nov 2021

Cited by 1 | Viewed by 3300

Abstract

Konjac (Amorphophallus konjac K. Koch) is a well-known tuberous vegetable belonging to the important medicinal family Araceae, and the plant grows from an underground tuber. Here, we used a “one-step seedling regeneration” tissue culture system to improve the plantlet regeneration efficiency [...] Read more.

Konjac (Amorphophallus konjac K. Koch) is a well-known tuberous vegetable belonging to the important medicinal family Araceae, and the plant grows from an underground tuber. Here, we used a “one-step seedling regeneration” tissue culture system to improve the plantlet regeneration efficiency of konjac using young leaves as an explant source. In the current study, we used several sterilization methods for tuber sterilization. Moreover, various plant growth regulator combinations were applied to achieve efficient somatic embryogenesis and plantlet regeneration. Our results showed that the optimal tuber sterilization was method C (75% alcohol for 15 s + 0.1% HgCl₂ for 15 min + washing by double-sterilized water three times). Three types of embryogenic calli were induced on full-strength Murashige and Skoog (MS) basal medium supplemented with 0.5 mg/L of 6-benzylaminopurine (6-BA), 0.5 mg/L of naphthaleneacetic acid (NAA), 1.0 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D), and 30 g/L of sucrose. Of the three types of embryogenic calli, only type Ⅲ further regenerated plantlets, with a callus induction rate of 55.73% and a seedling induction rate of 92.73%. This suggests that the addition of the above hormones gives the optimal callus induction. The proliferation rate achieved was 38% on the MS basal medium containing 1.0 mg/L of 6-BA, 1.0 mg/L of indolebutyric acid (IBA), 0.2 mg/L of kinetin (KT), and 50 g/L of sucrose. The one-step seedling formation achieved in MS medium contained 2.0 mg/L of 6-BA, 0.5 mg/L of NAA, 0.1 mg/L of gibberellic acid (GA₃), and 30 g/L of sucrose, and the number of regenerated shoots per explants was 6 ± 2. Therefore, we establish a one-step seedling regeneration system through indirect plant regeneration, which shortens the time for konjac in vitro regeneration, significantly increased the micropropagation efficiency, and decreased the cost of the konjac tissue culture. Full article

(This article belongs to the Special Issue Metabolic Engineering or Tissue Culture Technology for Medicinal and Horticultural Plants)

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15 pages, 2848 KiB

Open AccessArticle

Inferring the Potential Geographic Distribution and Reasons for the Endangered Status of the Tree Fern, Sphaeropteris lepifera, in Lingnan, China Using a Small Sample Size

by Xueying Wei, AJ Harris, Yuwen Cui, Yangwu Dai, Hanjia Hu, Xiaoling Yu, Rihong Jiang and Faguo Wang

Horticulturae 2021, 7(11), 496; https://doi.org/10.3390/horticulturae7110496 - 15 Nov 2021

Cited by 3 | Viewed by 3728

Abstract

In this study, we investigated suitable habitats for the endangered tree fern, Sphaeropteris lepifera (J. Sm. ex Hook.) R.M. Tryon, based on fieldwork, ecological niche modeling, and regression approaches. We combined these data with the characterization of spore germination and gametophytic development in [...] Read more.

In this study, we investigated suitable habitats for the endangered tree fern, Sphaeropteris lepifera (J. Sm. ex Hook.) R.M. Tryon, based on fieldwork, ecological niche modeling, and regression approaches. We combined these data with the characterization of spore germination and gametophytic development in the laboratory to assess the reasons why S. lepifera is endangered and to propose a conservation strategy that focuses on suitable sites for reintroduction and accounts for the ecology and biphasic life cycle of the species. Our methods represent an integration of process- and correlation-based approaches to understanding the distributional patterns of this species, and this combined approach, while uncommonly applied, is a more robust strategy than either approach used in isolation. Our ecological niche models indicated that cold temperature extremes, temperature stability over long- and short-terms, and the seasonality of precipitation were among the most important abiotic environmental factors affecting the distribution of S. lepifera among the variables that we measured. Moreover, distribution of this fern species is also strongly influenced by the timing of development of male and female gametes. Additionally, we observed that slope aspect, specifically south-facing slopes, facilitates more incoming sunlight for mature trees, and simultaneously, provides greater, much-needed shade for fiddleheads on account of the canopy being denser. We believe that our study can provide important guidance on the restoration of S. lepifera in the wild. Specifically, potential restoration areas can be screened for the specific environmental factors that we infer to have a critical impact on the survival of the species. Full article

(This article belongs to the Special Issue Neglected and Underutilized Plant Species in Horticultural and Ornamental Systems: Perspectives for Biodiversity, Nutraceuticals and Agricultural Sustainability)

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23 pages, 1247 KiB

Open AccessArticle

Mango Endophyte and Epiphyte Microbiome Composition during Fruit Development and Post-Harvest Stages

by Malick Bill, Lizyben Chidamba, Jarishma Keriuscia Gokul and Lise Korsten

Horticulturae 2021, 7(11), 495; https://doi.org/10.3390/horticulturae7110495 - 15 Nov 2021

Cited by 9 | Viewed by 2912

Abstract

The influence of the development stage and post-harvest handling on the microbial composition of mango fruit plays a central role in fruit health. Hence, the composition of fungal and bacterial microbiota on the anthoplane, fructoplane, stems and stem-end pulp of mango during fruit [...] Read more.

The influence of the development stage and post-harvest handling on the microbial composition of mango fruit plays a central role in fruit health. Hence, the composition of fungal and bacterial microbiota on the anthoplane, fructoplane, stems and stem-end pulp of mango during fruit development and post-harvest handling were determined using next-generation sequencing of the internal transcribed spacer and 16S rRNA regions. At full bloom, the inflorescence had the richest fungal and bacterial communities. The young developing fruit exhibited lower fungal richness and diversities in comparison to the intermediate and fully developed fruit stages on the fructoplane. At the post-harvest stage, lower fungal and bacterial diversities were observed following prochloraz treatment both on the fructoplane and stem-end pulp. Ascomycota (52.8%) and Basidiomycota (43.2%) were the most dominant fungal phyla, while Penicillium, Botryosphaeria, Alternaria and Mucor were detected as the known post-harvest decay-causing fungal genera. The Cyanobacteria (35.6%), Firmicutes (26.1%) and Proteobacteria (23.1%) were the most dominant bacterial phyla. Changes in the presence of Bacillus subtilis following post-harvest interventions such as prochloraz suggested a non-target effect of the fungicide. The present study, therefore, provides the primary baseline data on mango fungal and bacterial diversity and composition, which can be foundational in the development of effective disease (stem-end rot) management strategies. Full article

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10 pages, 2158 KiB

Open AccessFeature PaperArticle

Cryopreservation of Hazelnut (Corylus avellana L.) Axillary Buds from In Vitro Shoots Using the Droplet Vitrification Method

by Alessandra Sgueglia, Andrea Frattarelli, Adele Gentile, Gaia Urbinati, Simona Lucioli, Maria Antonietta Germanà and Emilia Caboni

Horticulturae 2021, 7(11), 494; https://doi.org/10.3390/horticulturae7110494 - 15 Nov 2021

Cited by 2 | Viewed by 1953

Abstract

Cryopreservation by droplet vitrification was applied to hazelnut (Corylus avellana L.). axillary buds of the Italian cultivated variety Tonda Gentile Romana, which were collected from in vitro growing shoots, immersed in ice cooled PVS2 or PVS3 for 60 or 90 min, then [...] Read more.

Cryopreservation by droplet vitrification was applied to hazelnut (Corylus avellana L.). axillary buds of the Italian cultivated variety Tonda Gentile Romana, which were collected from in vitro growing shoots, immersed in ice cooled PVS2 or PVS3 for 60 or 90 min, then transferred to a droplet of vitrification solution, placed on a strip of aluminium foil, and plunged into liquid nitrogen (LN). Additionally, the effect on the recovery of the mother plant after cryopreservation was evaluated, following a cold pre-treatment at 4 °C for 3 months. The highest regrowth percentage (56.7%) was obtained after applying PVS3 for 60 min, while the application of PVS2 for the same amount of time reduced regrowth to 41.5%. Increasing the exposure to vitrification solutions to 90 min reduced regrowth to 43.3% when PVS3 was applied, and 35.6% if PVS2 was used. The cold pre-treatment on the mother plant did not significantly improve overall regrowth. The cryopreservation process did not decline the rooting ability of the recovered shoots. Full article

(This article belongs to the Collection Application of Tissue Culture to Horticulture)

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51 pages, 1031 KiB

Open AccessFeature PaperReview

Sterols and Triterpene Diols in Virgin Olive Oil: A Comprehensive Review on Their Properties and Significance, with a Special Emphasis on the Influence of Variety and Ripening Degree

by Marina Lukić, Igor Lukić and Tihomir Moslavac

Horticulturae 2021, 7(11), 493; https://doi.org/10.3390/horticulturae7110493 - 13 Nov 2021

Cited by 21 | Viewed by 5719

Abstract

Olive oil is considered one of the most valuable vegetable oils and is highly appreciated by consumers for its specific and distinguishable taste and aroma, as well as its nutritional value. Sterols and triterpene diols are important carriers of bioactive properties of olive [...] Read more.

Olive oil is considered one of the most valuable vegetable oils and is highly appreciated by consumers for its specific and distinguishable taste and aroma, as well as its nutritional value. Sterols and triterpene diols are important carriers of bioactive properties of olive oil and are responsible for some of the beneficial effects of its consumption on human health, such as lowering serum LDL-cholesterol levels and significantly reducing the risk of cardiovascular diseases. The concentration of total sterols and the proportions of particular sterols and triterpene diols are among the parameters used to verify and prove the authenticity of olive oil in accordance with the EU and other countries’ regulations. Finally, their composition has been shown to have high discrimination potential for ensuring traceability with respect to variety, geographical origin, harvest date, and other factors. For these reasons, the research on sterols and triterpene diols in olive oil is an ever-growing field of scientific interest with great practical importance. This review focuses on all the important aspects of sterols and triterpene diols in olive oil, from their chemical structure, biosynthesis, occurrence and role in plants, health benefits, and their use in official controls of olive oil purity and authenticity, to a conclusive survey on the recent findings about the effects of different factors of influence on their content and composition, with a detailed comparative analysis of studies that investigated the effects of the two most important factors, variety and ripening degree. Full article

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

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17 pages, 70548 KiB

Open AccessArticle

SwinGD: A Robust Grape Bunch Detection Model Based on Swin Transformer in Complex Vineyard Environment

by Jinhai Wang, Zongyin Zhang, Lufeng Luo, Wenbo Zhu, Jianwen Chen and Wei Wang

Horticulturae 2021, 7(11), 492; https://doi.org/10.3390/horticulturae7110492 - 12 Nov 2021

Cited by 33 | Viewed by 4655

Abstract

Accurate recognition of fruits in the orchard is an important step for robot picking in the natural environment, since many CNN models have a low recognition rate when dealing with irregularly shaped and very dense fruits, such as a grape bunch. It is [...] Read more.

Accurate recognition of fruits in the orchard is an important step for robot picking in the natural environment, since many CNN models have a low recognition rate when dealing with irregularly shaped and very dense fruits, such as a grape bunch. It is a new trend to use a transformer structure and apply it to a computer vision domain for image processing. This paper provides Swin Transformer and DETR models to achieve grape bunch detection. Additionally, they are compared with traditional CNN models, such as Faster-RCNN, SSD, and YOLO. In addition, the optimal number of stages for a Swin Transformer through experiments is selected. Furthermore, the latest YOLOX model is also used to make a comparison with the Swin Transformer, and the experimental results show that YOLOX has higher accuracy and better detection effect. The above models are trained under red grape datasets collected under natural light. In addition, the dataset is expanded through image data augmentation to achieve a better training effect. After 200 epochs of training, SwinGD obtained an exciting mAP value of 94% when IoU = 0.5. In case of overexposure, overdarkness, and occlusion, SwinGD can recognize more accurately and robustly compared with other models. At the same time, SwinGD still has a better effect when dealing with dense grape bunches. Furthermore, 100 pictures of grapes containing 655 grape bunches are downloaded from Baidu pictures to detect the effect. The Swin Transformer has an accuracy of 91.5%. In order to verify the universality of SwinGD, we conducted a test under green grape images. The experimental results show that SwinGD has a good effect in practical application. The success of SwinGD provides a new solution for precision harvesting in agriculture. Full article

(This article belongs to the Special Issue Recent Advances in Horticultural Practices for Strawberries and Other Small Fruit Crops)

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12 pages, 1748 KiB

Open AccessArticle

Optimization of Caffeic Acid Extraction from Dendropanax morbifera Leaves Using Response Surface Methodology and Determination of Polyphenols and Antioxidant Properties

by Ming Zhang, Ting Bu, Shuilin Liu and Sooah Kim

Horticulturae 2021, 7(11), 491; https://doi.org/10.3390/horticulturae7110491 - 12 Nov 2021

Cited by 5 | Viewed by 1996

Abstract

The aim of this study was to optimize the extraction method for caffeic acid from the leaves of Dendropanax morbifera using response surface methodology (RSM), and subsequently determine the polyphenolic content and antioxidant capacity of the D. morbifera leaves extracts. The extraction process [...] Read more.

The aim of this study was to optimize the extraction method for caffeic acid from the leaves of Dendropanax morbifera using response surface methodology (RSM), and subsequently determine the polyphenolic content and antioxidant capacity of the D. morbifera leaves extracts. The extraction process considered operating variables such as solvent concentration, extraction temperature, and extraction time, which were optimized via Box–Behnken experimental design. In addition, the antioxidant capacity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The optimal extraction conditions of 41.23% (v/v) methanol concentration, at 88.61 °C, and 1.86 h produced a maximum caffeic acid (CA) yield of 20.35 mg/g. Additionally, total polyphenols, total tannins, and total flavonoids contents in the leaves extracts of D. morbifera were 32.48 ± 2.05 mg GAE (gallic acid equivalents)/g, 17.61 ± 2.61 mg GAE/g, and 9.14 ± 0.17 mg QE (quercetin equivalents)/g, respectively. The results showed that methanol extracts exhibited an IC50 of approximately 14.3 mg AAE (ascorbic acid equivalent)/g. The results suggested that the extracts of D. morbifera leaves contain potential antioxidant activity, and could be a good source of functional food and used in medicinal applications. Full article

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12 pages, 1344 KiB

Open AccessArticle

Non-Deep Physiological Dormancy in Seed and Germination Requirements of Lysimachia coreana Nakai

by Saeng Geul Baek, Jin Hyun Im, Myeong Ja Kwak, Cho Hee Park, Mi Hyun Lee, Chae Sun Na and Su Young Woo

Horticulturae 2021, 7(11), 490; https://doi.org/10.3390/horticulturae7110490 - 12 Nov 2021

Cited by 4 | Viewed by 2240

Abstract

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA₃) on seed germination at different [...] Read more.

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA₃) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L⁻¹ GA₃. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA₃ demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L⁻¹ GA₃ (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA₃ treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L⁻¹ GA₃ treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking. Full article

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24 pages, 5430 KiB

Open AccessArticle

Using a Hybrid Neural Network Model DCNN–LSTM for Image-Based Nitrogen Nutrition Diagnosis in Muskmelon

by Liying Chang, Daren Li, Muhammad Khalid Hameed, Yilu Yin, Danfeng Huang and Qingliang Niu

Horticulturae 2021, 7(11), 489; https://doi.org/10.3390/horticulturae7110489 - 12 Nov 2021

Cited by 8 | Viewed by 3410

Abstract

In precision agriculture, the nitrogen level is significantly important for establishing phenotype, quality and yield of crops. It cannot be achieved in the future without appropriate nitrogen fertilizer application. Moreover, a convenient and real-time advance technology for nitrogen nutrition diagnosis of crops is [...] Read more.

In precision agriculture, the nitrogen level is significantly important for establishing phenotype, quality and yield of crops. It cannot be achieved in the future without appropriate nitrogen fertilizer application. Moreover, a convenient and real-time advance technology for nitrogen nutrition diagnosis of crops is a prerequisite for an efficient and reasonable nitrogen-fertilizer management system. With the development of research on plant phenotype and artificial intelligence technology in agriculture, deep learning has demonstrated a great potential in agriculture for recognizing nondestructive nitrogen nutrition diagnosis in plants by automation and high throughput at a low cost. To build a nitrogen nutrient-diagnosis model, muskmelons were cultivated under different nitrogen levels in a greenhouse. The digital images of canopy leaves and the environmental factors (light and temperature) during the growth period of muskmelons were tracked and analyzed. The nitrogen concentrations of the plants were measured, we successfully constructed and trained machine-learning- and deep-learning models based on the traditional backpropagation neural network (BPNN), the emerging convolution neural network (CNN), the deep convolution neural network (DCNN) and the long short-term memory (LSTM) for the nitrogen nutrition diagnosis of muskmelon. The adjusted determination coefficient (R²) and mean square error (MSE) between the predicted values and measured values of nitrogen concentration were adopted to evaluate the models’ accuracy. The values were R² = 0.567 and MSE = 0.429 for BPNN model; R² = 0.376 and MSE = 0.628 for CNN model; R² = 0.686 and MSE = 0.355 for deep convolution neural network (DCNN) model; and R² = 0.904 and MSE = 0.123 for the hybrid model DCNN–LSTM. Therefore, DCNN–LSTM shows the highest accuracy in predicting the nitrogen content of muskmelon. Our findings highlight a base for achieving a convenient, precise and intelligent diagnosis of nitrogen nutrition in muskmelon. Full article

(This article belongs to the Topic Soil Fertility and Plant Nutrition for Sustainable Agriculture)

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11 pages, 4896 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Selenium Enrichment of Green and Red Lettuce and the Induction of Radical Scavenging Potential

by Muna Ali Abdalla, Jürgen E. Wick, Ibukun M. Famuyide, Lyndy J. McGaw and Karl H. Mühling

Horticulturae 2021, 7(11), 488; https://doi.org/10.3390/horticulturae7110488 - 11 Nov 2021

Cited by 8 | Viewed by 2172

Abstract

Selenium (Se)-enriched vegetables are promising dietary sources of Se, which provides beneficial biological effects in humans. In this study, we investigated the effects of foliar application of Se on hydroponically grown multi-leaf green (V1) and red (V2) lettuce plants. Three selenate (SeIV) amendment [...] Read more.

Selenium (Se)-enriched vegetables are promising dietary sources of Se, which provides beneficial biological effects in humans. In this study, we investigated the effects of foliar application of Se on hydroponically grown multi-leaf green (V1) and red (V2) lettuce plants. Three selenate (SeIV) amendment levels were evaluated for their influence on plant growth, elemental composition and radical scavenging capacity. Lettuce heads biofortified with 0.598 mg Se plant⁻¹ accumulated 19.6–23.6 and 14.9–17.6 μg Se g⁻¹ DM in the multi-leaf green (V1) and red (V2) lettuce plants, respectively. The accumulated Se levels can contribute significantly to the recommended dietary allowance of 70 µg day⁻¹ for adult men and 60 µg day⁻¹ for adult women. Accordingly, both V1 and V2 lettuce cultivars grown under the Se3 foliar application condition can cover the daily requirement for adult men by approximately 100% and 85% to 100%, respectively, by consuming 75–90 g or 100 g fresh weight from V1 or V2, respectively. The ABTS radical scavenging potential of green lettuce was induced at Se2 and Se3 foliar application levels, where the IC₅₀ was 1.124 ± 0.09 μg mL⁻¹ at Se0 and improved to 0.795 ± 0.03 and 0.697 ± 0.01 μg mL⁻¹, respectively. There was no cytotoxicity against Vero kidney cells among all treated lettuce plants at the highest concentration tested of 1 mg/mL. Finally, a further focused investigation of the metabolic profile of lettuce plants under varied Se levels needs to be investigated in future studies. Full article

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

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12 pages, 2426 KiB

Open AccessEditor’s ChoiceArticle

Effects of Berry Thinning on the Physicochemical, Aromatic, and Sensory Properties of Shine Muscat Grapes

by Kyeong-Ok Choi, Dongjun Im, Seo Jun Park, Dong Hoon Lee, Su Jin Kim and Youn Young Hur

Horticulturae 2021, 7(11), 487; https://doi.org/10.3390/horticulturae7110487 - 11 Nov 2021

Cited by 11 | Viewed by 5022

Abstract

The effects of the level of berry thinning (30% and 50% berry removal) on the quality and sensory properties of Shine Muscat grapes were investigated. As berry thinning increased, the total soluble solids content increased and titratable acidity decreased. Berry thinning increased berry [...] Read more.

The effects of the level of berry thinning (30% and 50% berry removal) on the quality and sensory properties of Shine Muscat grapes were investigated. As berry thinning increased, the total soluble solids content increased and titratable acidity decreased. Berry thinning increased berry size and cluster weight but caused no change in individual berry weight. Phenolic concentrations as measured by total phenolic, proanthocyanidin, and polymeric tannin concentrations tended to increase with an increase in berry thinning. Gas chromatographic analysis indicated that C6-compounds were the significant constituents of volatile alcohols and aldehydes; linalool was the most abundant monoterpene. Odor activity analysis indicated that (E)-2-hexen-1-ol, (E)-2-hexenal, 1-hexanal, (Z)-3-hexenal, (E)-β-damascenone, linalool, and (E)-linalool oxide were active odorants. Berry thinning increased the accumulation of linalool contributing to high sensory flavor scores in thinned berries. Furthermore, its oxidized derivative-linalool oxide-contributed to enhancing the Muscat flavor. In conclusion, berry thinning induced compositional changes in Shine Muscat grape berries by accelerating the ripening rate, contribution to improved sensory properties. Full article

(This article belongs to the Section Viticulture)

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14 pages, 1682 KiB

Open AccessArticle

Assessment of Plant Growth Regulators and Carbon Sources on the Germination and Growth Process of Dandelion (Taraxacum officinale G.H. Weber ex Wiggers) under In Vitro Conditions

by María Eugenia Martínez, Lorena Jorquera, Paola Poirrier, Katy Díaz and Rolando Chamy

Horticulturae 2021, 7(11), 486; https://doi.org/10.3390/horticulturae7110486 - 11 Nov 2021

Cited by 1 | Viewed by 1988

Abstract

There are several studies on the medicinal properties of dandelions (Taraxacum officinale), but few studies are aimed at understanding the in vitro germination process of this plant to improve its propagation. This research was focused on studying in vitro seed germination [...] Read more.

There are several studies on the medicinal properties of dandelions (Taraxacum officinale), but few studies are aimed at understanding the in vitro germination process of this plant to improve its propagation. This research was focused on studying in vitro seed germination and development of seedlings under different carbon sources, glucose (GLU) or sucrose (SUC) and its concentrations (1.0–5.5%). Additionally, the effect of supplementation with plant growth regulators (PGRs) was studied, measuring the germination capacity, uncertainty and synchrony. Germination was promoted under low carbon source concentrations (≤2.3%), whereas higher concentrations (≥3.2%) had a detrimental effect on this process. GLU allowed the final germination percentages to be slightly better than SUC. Uniformity and synchrony values improved with the presence of PGRs. Results suggested that the best condition to assess T. officinale seed germination is in a medium containing GLU 2.3%, 0.5 mg/L 1-Naphthaleneacetic acid (NAA) and 0.5 mg/L 6-Benzylaminopurine acid (BAP). After germination, the best condition for optimal growth of T. officinale seedlings was 1.0% SUC supplemented with 0.225 mg/L of NAA and 3.0 mg/L of BAP for initial shoot development. The survival rate was 97% after greenhouse acclimatization. This new method of germination was implemented for the massive propagation of T. officinale for further medicinal studies. Full article

(This article belongs to the Section Propagation and Seeds)

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Open AccessFeature PaperArticle

Supplementary Light with Increased Blue Fraction Accelerates Emergence and Improves Development of the Inflorescence in Aechmea, Guzmania and Vriesea

by Elahe Javadi Asayesh, Sasan Aliniaeifard, Naser Askari, Mahmood Reza Roozban, Mohammadhadi Sobhani, Georgios Tsaniklidis, Ernst J. Woltering and Dimitrios Fanourakis

Horticulturae 2021, 7(11), 485; https://doi.org/10.3390/horticulturae7110485 - 10 Nov 2021

Cited by 23 | Viewed by 3301

Abstract

In protected cultivation, increasing the light level via supplementary lighting (SL) is critical to improve external quality, especially in periods with low light availability. Despite wide applications, the effect of light quality remains understated. In this study, the effect of SL quality and [...] Read more.

In protected cultivation, increasing the light level via supplementary lighting (SL) is critical to improve external quality, especially in periods with low light availability. Despite wide applications, the effect of light quality remains understated. In this study, the effect of SL quality and nutrient solution electrical conductivity (EC) on growth and flowering of three bromeliad species was investigated. Treatments included solar light, and this supplemented with R90B10 [90% red (R) and 10% blue (B)], R80B20 (80% R and 20% B), and R70B30 (70% R and 30% B). These were combined with an EC of 1 and 2 dS m^-l. Irrespective of the light treatment, the higher EC promoted growth, inflorescence emergence, and development in Aechmea fasciata (Lindl.) Baker, whereas adverse effects were noted in Guzmania and Vriesea. The higher EC-induced negative effect in Guzmania and Vriesea was slightly alleviated by SL. With few notable exceptions, SL exerted limited effects on photosynthetic functionality. Depending on the species, SL improved external quality traits. In all species, SL increased root and inflorescence weight and stimulated biomass allocation to generative organs. It also accelerated inflorescence emergence and promoted inflorescence development. In this way, the time to commercial development stage was considerably shortened. These effects were more prominent at R80B20 and R70B30. Under those conditions, for instance, inflorescence emergence occurred 3–5 weeks earlier than in the control, depending on the species. In conclusion, SL with increased B proportion leads to shorter production period owing to faster emergence and improved development of the inflorescence and is recommended for commercial use. Full article

(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)

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Horticulturae, Volume 7, Issue 11 (November 2021) – 99 articles

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