Horticulturae

6 pages, 710 KiB

Open AccessBrief Report

The Relationship between Shape and Size of Diaspores Depends on Being Seeds or Fruits

by Luís Silva Dias and Alexandra Soveral Dias

Horticulturae 2019, 5(3), 65; https://doi.org/10.3390/horticulturae5030065 - 09 Sep 2019

Cited by 4 | Viewed by 3110

The relationship between the size and shape of diaspores was investigated in angiosperms and gymnosperms including determining if being a seed or fruit was a factor. Size was expressed as volume and shape as the departure from a perfect idealized sphere. Departure from [...] Read more.

The relationship between the size and shape of diaspores was investigated in angiosperms and gymnosperms including determining if being a seed or fruit was a factor. Size was expressed as volume and shape as the departure from a perfect idealized sphere. Departure from sphericity in seeds was found to be independent from volume. Conversely, an inverse relationship was found between departure from sphericity and volume in fruits. Therefore, whether a diaspore is a seed or a fruit should be considered and included in analyses when ecological, functional or evolutionary correlates of diaspore morphology are under investigation. Full article

(This article belongs to the Special Issue The Geometry of Seeds: Seed Shape Definition and Quantification Based on Geometrical Diversity)

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7 pages, 1629 KiB

Open AccessArticle

In Vitro Propagation and Acclimatization of Dragon Tree (Dracaena draco)

by Alexis Galus, Ali Chenari Bouket and Lassaad Belbahri

Horticulturae 2019, 5(3), 64; https://doi.org/10.3390/horticulturae5030064 - 06 Sep 2019

Cited by 4 | Viewed by 6317

Abstract

In this study, an efficient in vitro procedure was developed for bud induction, rooting of developing shoots and greenhouse acclimatization of young plantlets of dragon tree (Dracaena draco). Effects of media (S1 (1 mg/L KIN and 1 mg/L NAA), S2 (3 [...] Read more.

In this study, an efficient in vitro procedure was developed for bud induction, rooting of developing shoots and greenhouse acclimatization of young plantlets of dragon tree (Dracaena draco). Effects of media (S1 (1 mg/L KIN and 1 mg/L NAA), S2 (3 mg/L KIN and 1 mg/L IAA), S3 (1 mg/L BAP and 2 mg/L IBA) and S4 (1 mg/L BAP and 1 mg/L NAA)) on shoot induction and media (R1 (0 mg/L IBA), R2 (0.5 mg/L IBA), R3 (1 mg/L IBA), and R4 (2 mg/L IBA)) on root induction were examined in order to find optimal plant hormone concentrations for efficient Dracaena draco dormant bud development and subsequent rooting. The best shoot induction and rooting media were S1 and S2, and R3 and R4, respectively. Dormant buds from one-year-old Dracaena draco plants submitted to this in vitro procedure allowed successful recovery of up to 8 individuals per explant used. In vitro grown plants were successfully acclimated in the greenhouse. The potential of this in vitro procedure for multiplication of this endangered tree is discussed in this report. Full article

(This article belongs to the Special Issue Innovation in Propagation of Fruit, Vegetable and Ornamental Plants)

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Graphical abstract

17 pages, 986 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Influence of Preharvest Gibberellic Acid Treatments on Postharvest Quality of Minimally Processed Leaf Lettuce and Rocket

by Alessandro Miceli, Filippo Vetrano, Leo Sabatino, Fabio D’Anna and Alessandra Moncada

Horticulturae 2019, 5(3), 63; https://doi.org/10.3390/horticulturae5030063 - 02 Sep 2019

Cited by 25 | Viewed by 4300

Abstract

Plant growth regulators are used in high-value vegetable crops during cultivation and after harvest to increase yield, enhance crop management, and improve or retain the produce quality. The aim of this work was to evaluate the quality characteristics during cold storage of minimally [...] Read more.

Plant growth regulators are used in high-value vegetable crops during cultivation and after harvest to increase yield, enhance crop management, and improve or retain the produce quality. The aim of this work was to evaluate the quality characteristics during cold storage of minimally processed leaf lettuce and rocket, obtained from plants grown in a hydroponic floating system with mineral nutrient solutions (MNS) containing different levels of gibberellic acid (GA₃). Plants were grown in greenhouse conditions on nutrient solutions containing 0, 10⁻⁸, and 10⁻⁶ M GA₃. At harvest, lettuce and rocket were immediately processed as fresh-cut vegetables and stored for 21 d at 4 °C. After processing, weight loss, total soluble solids, titratable acidity, ascorbic acid and nitrate content, leaf color characteristics, and overall quality were evaluated. Adding 10⁻⁶ M GA₃ to the MNS of a floating system significantly increased the yield of leaf lettuce and rocket plants and of minimally-processed leaves. In addition, preharvest GA₃ treatments had positive effects on delaying senescence and enhancing shelf-life of minimally processed lettuce and rocket. The slowed senescence of GA₃-treated samples maintained an overall quality over the threshold of marketability in both lettuce and rocket for up to 21 d of cold storage. Full article

(This article belongs to the Special Issue Plant Growth Regulators for Improving the Yield and Quality of Horticultural Crops)

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13 pages, 2602 KiB

Open AccessArticle

Methyl Jasmonate and Salinity Increase Anthocyanin Accumulation in Radish Sprouts

by Masaru Sakamoto and Takahiro Suzuki

Horticulturae 2019, 5(3), 62; https://doi.org/10.3390/horticulturae5030062 - 02 Sep 2019

Cited by 18 | Viewed by 3686

Abstract

Plant secondary metabolites with antioxidant properties, such as anthocyanins, are considered to have an important commercial value for some crops. Although anthocyanin concentration increases in response to various stimuli in plants, the mechanism of anthocyanin accumulation under multiple stimuli is not yet well [...] Read more.

Plant secondary metabolites with antioxidant properties, such as anthocyanins, are considered to have an important commercial value for some crops. Although anthocyanin concentration increases in response to various stimuli in plants, the mechanism of anthocyanin accumulation under multiple stimuli is not yet well understood. Here, we examined the effects of methyl jasmonate (MJ) and salinity on anthocyanin accumulation in radish (Raphanus sativus) sprouts. MJ treatments induced anthocyanin accumulation, which was enhanced by simultaneous treatment with salinity (200 mM NaCl), accompanied by growth restrictions. Sprouts treated with salinity alone did not induce anthocyanin accumulation, although sprout growth was restricted. Co-treatment with MJ and salinity increased hydrogen peroxide, total phenol content, and radical scavenging capacity more strongly than was achieved when each treatment was applied singly. Accumulation of anthocyanin was dependent on NaCl concentration and light intensity. Changing MJ and salinity treatment periods had different effects on anthocyanin accumulation and growth restriction, indicating that these phenomena might be differentially regulated. These results may provide an effective anthocyanin accumulation method without reducing plant biomass. Full article

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12 pages, 617 KiB

Open AccessEditor’s ChoiceArticle

Does Inoculation with Arbuscular Mycorrhizal Fungi Reduce Trunk Disease in Grapevine Rootstocks?

by Taylor Holland, Patricia Bowen, Vasilis Kokkoris, Jose Ramon Urbez-Torres and Miranda Hart

Horticulturae 2019, 5(3), 61; https://doi.org/10.3390/horticulturae5030061 - 28 Aug 2019

Cited by 15 | Viewed by 4483

Abstract

Ilyonectria is a weak pathogen known for causing black foot disease in young vines, infecting roots and vascular tissues at the basal end of the rootstock and restricting the movement of water and nutrients. This negatively impacts vine establishment during transplant into the [...] Read more.

Ilyonectria is a weak pathogen known for causing black foot disease in young vines, infecting roots and vascular tissues at the basal end of the rootstock and restricting the movement of water and nutrients. This negatively impacts vine establishment during transplant into the vineyard. Arbuscular mycorrhizal (AM) fungi are symbiotic fungi that associate with most plants and have been shown to mitigate the infection and effect of pathogens. This greenhouse study was designed to determine if the mycorrhizal fungi could mitigate Ilyonectria infection and whether this was dependent on inoculation timing. ‘Riparia gloire’ grapevine rootstocks (Vitis riparia) were infected with Ilyonectria either after AM fungi, at the same time as AM fungi, or to roots that were not inoculated by AM fungi. We measured the abundance using specific markers for both the pathogen and AM fungi. Colonization by AM fungi did not suppress Ilyonectria, but instead increased the abundance of Ilyonectria. Further, mycorrhizal rootstocks did not have enhanced growth effects on physiological parameters when compared to non-mycorrhizal rootstocks. These findings stand in contrast to the general perception that AM fungi provide protection against root pathogens. Full article

(This article belongs to the Special Issue Horticultural Crop Microbiomes)

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18 pages, 6686 KiB

Open AccessFeature PaperOpinion

Seed Shape Description and Quantification by Comparison with Geometric Models

by Emilio Cervantes and José Javier Martín Gómez

Horticulturae 2019, 5(3), 60; https://doi.org/10.3390/horticulturae5030060 - 19 Aug 2019

Cited by 25 | Viewed by 12081

Abstract

Modern methods of image analysis are based on the coordinates of the points making the silhouette of an image and allow the comparison between seed shape in different species and varieties. Nevertheless, these methods miss an important reference point because they do not [...] Read more.

Modern methods of image analysis are based on the coordinates of the points making the silhouette of an image and allow the comparison between seed shape in different species and varieties. Nevertheless, these methods miss an important reference point because they do not take into consideration the similarity of seeds with geometrical figures. We propose a method based on the comparison of the bi-dimensional images of seeds with geometric figures. First, we describe six geometric figures that may be used as models for shape description and quantification and later on, we give an overview with examples of some of the types of seed morphology in angiosperms including families of horticultural plants and addressing the question of how is the distribution of seed shape in these families. The relationship between seed shape and other characteristics of plant species is discussed. Full article

(This article belongs to the Special Issue The Geometry of Seeds: Seed Shape Definition and Quantification Based on Geometrical Diversity)

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13 pages, 5092 KiB

Open AccessArticle

Exploiting Olive Mill Byproducts and Other Waste for Organic Weed Management

by Ashraf M. Tubeileh, Justin T. Schnorf, Israel Mondragon and Gary A. Gray

Horticulturae 2019, 5(3), 59; https://doi.org/10.3390/horticulturae5030059 - 09 Aug 2019

Cited by 6 | Viewed by 3422

Abstract

Weed management represents one of the most serious and costly challenges in organic crop production systems. Agricultural waste/byproducts might present phytotoxicity that can be exploited to control weeds. Two experiments were designed to study the effects of four concentrations of olive vegetation water [...] Read more.

Weed management represents one of the most serious and costly challenges in organic crop production systems. Agricultural waste/byproducts might present phytotoxicity that can be exploited to control weeds. Two experiments were designed to study the effects of four concentrations of olive vegetation water (OVW) and a control water treatment (with no OVW) on cheeseweed (Malva parviflora L.) seed germination in petri dishes and pots. In a third experiment, two rates of four composts (crop residue mix (CR), olive pomace (OP), dairy/horse manure (DM), and an OP/DM mix) were mixed into a clay‒loam soil at 0.10 or 0.20 L L⁻¹, to assess their effects on weed number and biomass, in addition to bell pepper (Capsicum annuum L.) growth. In the petri dish experiment, the three highest OVW concentrations completely prohibited germination during the five-week duration of the study. For the pot experiment, 25 mL application of OVW significantly delayed and reduced cheeseweed germination, with the reduction being proportional to the concentration of OVW. In the third experiment, composts reduced weed dry matter (composed mostly of purslane (Portulaca oleracea L.)), with the CR compost being the most effective, reducing total weed biomass by 67% compared to the control. CR10 and DM10 tended to increase bell pepper yields, although none of the plant parameters was significantly affected by the compost treatments. Full article

(This article belongs to the Special Issue Weed Management in Horticultural Production)

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9 pages, 623 KiB

Open AccessArticle

Incident Light and Leaf Age Influence Leaflet Element Concentrations of Cycas micronesica Trees

by Thomas E. Marler and Murukesan V. Krishnapillai

Horticulturae 2019, 5(3), 58; https://doi.org/10.3390/horticulturae5030058 - 07 Aug 2019

Cited by 7 | Viewed by 2606

Abstract

The need for improved knowledge on conservation and management of cycad species has generated recent interest in compiling a database on leaf nutrient concentrations. However, the sampling protocols have not been consistent among reports and the influences of some plant and habitat traits [...] Read more.

The need for improved knowledge on conservation and management of cycad species has generated recent interest in compiling a database on leaf nutrient concentrations. However, the sampling protocols have not been consistent among reports and the influences of some plant and habitat traits on the plasticity of cycad leaf nutrient concentrations has not been adequately determined. We used Cycas micronesica K.D. Hill trees to determine the role of incident light level and leaf age on leaflet content of 11 essential elements. Shade leaves exhibited increased mass-based concentration for nitrogen, phosphorus, and potassium above that of sun leaves. Shade leaves exhibited decreased area-based concentration for all of the macro- and micronutrients below that of sun leaves. Mass-based concentration of nitrogen, phosphorus, and potassium decreased with leaf age, and that of calcium, magnesium, iron, manganese, and zinc increased with leaf age. These findings indicate the relative leaf age and the amount of shade or incident light at the leaf level must be recorded and reported for leaf tissue studies in cycads in order to reduce ambiguity and ensure repeatability. Full article

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13 pages, 347 KiB

Open AccessArticle

Effective Analysis of Interactive Effects with Non-Normal Data Using the Aligned Rank Transform, ARTool and SAS^® University Edition

by Edward Durner

Horticulturae 2019, 5(3), 57; https://doi.org/10.3390/horticulturae5030057 - 03 Aug 2019

Cited by 9 | Viewed by 4763

Abstract

Most statistical techniques commonly used in horticultural research are parametric tests that are valid only for normal data with homogeneous variances. While parametric tests are robust when the data ‘slightly’ deviate from normality, a significant departure from normality leads to reduced power and [...] Read more.

Most statistical techniques commonly used in horticultural research are parametric tests that are valid only for normal data with homogeneous variances. While parametric tests are robust when the data ‘slightly’ deviate from normality, a significant departure from normality leads to reduced power and the probability of a type I error increases. Transformations often used to normalize non-normal data can be time consuming, cumbersome and confusing and common non-parametric tests are not appropriate for evaluating interactive effects common in horticultural research. The aligned rank transformation allows non-parametric testing for interactions and main effects using standard ANOVA techniques. This has not been widely adapted due to its rigorous mathematical nature, however, a downloadable (ARTool) is now available, which performs the math needed for the transformation. This study provides step-by-step instructions for integrating ARTool with the free edition of SAS (SAS University Edition) in an easily employed method for testing normality, transforming data with aligned ranks, and analysing data using standard ANOVAs. Full article

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10 pages, 2071 KiB

Open AccessFeature PaperReview

Securing Horticulture in a Changing Climate—A Mini Review

by Mehdi B. Bisbis, Nazim S. Gruda and Michael M. Blanke

Horticulturae 2019, 5(3), 56; https://doi.org/10.3390/horticulturae5030056 - 02 Aug 2019

Cited by 25 | Viewed by 6796

Abstract

(1) Background: Climate change is on the rise due to continuous greenhouse gas emissions from anthropogenic activities ever since the industrial revolution. Changing weather conditions are likely to have consequences for horticulture. (2) Objective and Methods: A short literature review was conducted, gathering [...] Read more.

(1) Background: Climate change is on the rise due to continuous greenhouse gas emissions from anthropogenic activities ever since the industrial revolution. Changing weather conditions are likely to have consequences for horticulture. (2) Objective and Methods: A short literature review was conducted, gathering findings on climate change and the impacts on the yield and product quality of special crops. (3) Results: Global warming will result in elevated temperatures and CO₂ concentrations in all seasons. Extreme weather events such as heat waves are also on the increase. In vegetables, physiological processes such as vernalization and winter chilling strongly rely on temperature. Therefore, heat stress may cause irregularities in yield production and planning the harvest. For fruit crops, frost poses a risk that is enhanced through climate change, as does a lack of chilling, as cold temperatures in the winter are required for flowering in the spring. Abiotic disorders in horticulture are also related to changing temperatures and humidity. The nutritional quality of special crops may be threatened by increasing rates of plant development and premature ripening at high temperatures. Quality traits such as sugars, acids, or antioxidant capacity may also shift as well. (4) Conclusions: Adapting to these new climate conditions means developing new climate-resilient varieties to maintain high production levels with superior quality. In this mini review, cultivation measures to mitigate adverse climate impacts are also discussed. Current developments and recent findings are presented, pointing out further steps toward adaptation and sustainable production. Full article

(This article belongs to the Special Issue Abiotic Stress Responses of Plants)

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10 pages, 905 KiB

Open AccessFeature PaperArticle

Improved Propagation and Growing Techniques for Oleander Nursery Production

by Leo Sabatino, Fabio D’Anna and Giovanni Iapichino

Horticulturae 2019, 5(3), 55; https://doi.org/10.3390/horticulturae5030055 - 01 Aug 2019

Cited by 2 | Viewed by 4824

Abstract

In the first trial, we examined rooting of stem cuttings in relation to number of nodes and indole-3-butyric acid (IBA) treatment in several Nerium oleander clones grown in Sicily. In a second trial, we tested the effect of different forcing dates and shading [...] Read more.

In the first trial, we examined rooting of stem cuttings in relation to number of nodes and indole-3-butyric acid (IBA) treatment in several Nerium oleander clones grown in Sicily. In a second trial, we tested the effect of different forcing dates and shading on oleander plants for gardens and natural landscapes. Three- and four-node cuttings, ranging in length from 10 to 14 cm, were significantly superior to two-node cuttings (8–10 cm long) in terms of rooting percentage and number of roots per cutting. The application of IBA improved rooting percentage and root number as compared to untreated control. Irrespective of IBA, rooting percentages ranged from 94% in clone 1 to 52% in clone 4. Shaded plants forced in October were significantly higher than those forced in November and in December. Beginning of flowering was delayed in unforced plants. Plants forced in October flowered significantly sooner (first decade of March) than unforced ones (first decade of May) and reached complete flowering almost two months earlier (last week of March).Shading had little effect on plants forced in October and in November as compared to unshaded plants in terms of start of flowering, but it slightly hastened beginning of flowering of December forced plants as compared to their unshaded counterparts. Full article

(This article belongs to the Special Issue Innovation in Propagation of Fruit, Vegetable and Ornamental Plants)

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11 pages, 3621 KiB

Open AccessFeature PaperArticle

Effect of Orchard Management Factors on Flesh Color of Two Red-Fleshed Apple Clones

by Annika Wellner, Eckhard Grimm and Moritz Knoche

Horticulturae 2019, 5(3), 54; https://doi.org/10.3390/horticulturae5030054 - 29 Jul 2019

Cited by 5 | Viewed by 3151

Abstract

Little is known about factors affecting anthocyanin biosynthesis in red-fleshed apples (Malus × domestica Borkh.). The objective was to establish the effects of orchard management factors on flesh anthocyanin content of dark-colored (DC) and light-colored (LC) apple clones. Flesh color was assessed [...] Read more.

Little is known about factors affecting anthocyanin biosynthesis in red-fleshed apples (Malus × domestica Borkh.). The objective was to establish the effects of orchard management factors on flesh anthocyanin content of dark-colored (DC) and light-colored (LC) apple clones. Flesh color was assessed by measuring color in the L, a, b mode using a spectrophotometer and predicting the anthocyanin content based on relationships between the absorption of a flesh extract at 530 nm and the L-value determined using a spectrophotometer (r² = 0.99 ***). Fruit from the DC clone were red by 86 days after full bloom (DAFB), whereas the LC clone began to color at 136 DAFB. Color intensity in both clones decreased from the top of the tree to the base. Further, the intensity of the flesh color of the DC clone decreased with shading (94% absorption of incident photosynthetic active radiation). Covering a fruit with a UV absorbing film (100% UV absorption) had no effect on flesh color in the DC clone but decreased color in the LC clone. Fruit thinning increased color in DC and LC fruit. There was little change in flesh color during storage. However, the DC clone developed severe flesh browning as storage progressed beyond 30 days. The results demonstrated that light (visible and UV wavelength) stimulated, whereas shade inhibited, anthocyanin biosynthesis in the flesh under orchard conditions. Full article

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13 pages, 2079 KiB

Open AccessArticle

Changes in Acetylene Reduction Activities and nifH Genes Associated with Field-Grown Sweet Potatoes with Different Nursery Farmers and Cultivars

by Kazuhito Itoh, Keisuke Ohashi, Nao Yakai, Fumihiko Adachi and Shohei Hayashi

Horticulturae 2019, 5(3), 53; https://doi.org/10.3390/horticulturae5030053 - 27 Jul 2019

Cited by 5 | Viewed by 3322

Abstract

Sweet potato cultivars obtained from different nursery farmers were cultivated in an experimental field from seedling-stage to harvest, and the acetylene reduction activity (ARA) of different parts of the plant as well as the nifH genes associated with the sweet potatoes were examined. [...] Read more.

Sweet potato cultivars obtained from different nursery farmers were cultivated in an experimental field from seedling-stage to harvest, and the acetylene reduction activity (ARA) of different parts of the plant as well as the nifH genes associated with the sweet potatoes were examined. The relationship between these parameters and the plant weights, nitrogen contents, and natural abundance of ¹⁵N was also considered. The highest ARA was detected in the tubers and in September. Fragments of a single type of nitrogenase reductase gene (nifH) were amplified, and most of them had similarities with those of Enterobacteriaceae in γ-Proteobacteria. In sweet potatoes from one nursery farm, Dickeya nifH was predominantly detected in all of the cultivars throughout cultivation. In sweet potatoes from another farm, on the other hand, a transition to Klebsiella and Phytobacter nifH was observed after the seedling stage. The N₂-fixing ability contributed to plant growth, and competition occurred between autochthonous and allochthonous bacterial communities in sweet potatoes. Full article

(This article belongs to the Special Issue Horticultural Crop Microbiomes)

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9 pages, 446 KiB

Open AccessFeature PaperArticle

Punicalagin Content and Antifungal Activity of Different Pomegranate (Punica ganatum L.) Genotypes

by Domenico Rongai, Patrizio Pulcini, Giovanni Di Lernia, Paolo Nota, Pjerin Preka and Filomena Milano

Horticulturae 2019, 5(3), 52; https://doi.org/10.3390/horticulturae5030052 - 16 Jul 2019

Cited by 29 | Viewed by 4512

Abstract

This study investigated the antifungal activity of a number of pomegranate genotypes. Since the main compound of pomegranate extract is punicalagin, an important substance involved in antifungal and antimicrobial activity, we analyzed the contents of punicalagin (α and β) in 21 different pomegranate [...] Read more.

This study investigated the antifungal activity of a number of pomegranate genotypes. Since the main compound of pomegranate extract is punicalagin, an important substance involved in antifungal and antimicrobial activity, we analyzed the contents of punicalagin (α and β) in 21 different pomegranate genotypes. Ellagic acid content, total phenolic content, acidity and pH were also determined. This work allowed us to determine which genotypes of pomegranate can be used to obtain extracts with the highest content of punicalagin, with the goal of developing a green alternative to synthetic pesticides. To improve the extraction system from pomegranate peel fruits, several different solvents were tested. All the pomegranate genotypes tested showed antifungal activity; some genotypes were able to almost completely inhibit the fungus, while others had very low inhibitory activity. Research results also showed that the use of water as a solvent for extraction is very effective, especially when it is combined with ethanol. This is very important for the practical use of the extracts since water is economical and environmentally friendly. The research showed that among the genotypes there is also great variability regarding the chemical parameters. Genotypes with a high phenolic and punicalagin content were significantly correlated with antifungal activity. All the other chemical parameters (pH, titratable acidity and ellagic acid content) were not correlated with antifungal activity. The results obtained indicate that the fruits of some pomegranate genotypes could be used to obtain extracts very rich in punicalagins and that these substances could be used as an alternative to synthetic products to control plant disease and improve the quality of the plant products, avoiding the impact of synthetic chemicals on the environment. Full article

(This article belongs to the Special Issue Natural Actives Molecules: A Sustainable Solution to Fight against Diseases and Pests of Vegetable and Fruit Crops)

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10 pages, 235 KiB

Open AccessArticle

Effect of LED Lighting and Gibberellic Acid Supplementation on Potted Ornamentals

by Taylor Mills-Ibibofori, Bruce L. Dunn, Niels Maness and Mark Payton

Horticulturae 2019, 5(3), 51; https://doi.org/10.3390/horticulturae5030051 - 15 Jul 2019

Cited by 7 | Viewed by 4143

Abstract

Use of light emitting diode (LED) technology is beginning to replace traditional lighting in greenhouses. This research focused on the effects of LED lighting and gibberellic acid supplementation on growth and flowering of Dahlia spp. ‘Karma Serena’, Liatris spicata ‘Kobold’, and Lilium asiatic [...] Read more.

Use of light emitting diode (LED) technology is beginning to replace traditional lighting in greenhouses. This research focused on the effects of LED lighting and gibberellic acid supplementation on growth and flowering of Dahlia spp. ‘Karma Serena’, Liatris spicata ‘Kobold’, and Lilium asiatic ‘Yellow Cocotte’. Light treatments, used to extend photoperiod, included LED flowering lamps and halogen lamps that emitted a combination of red + far-red + white, red + white, and broad spectrum from late fall to early spring. Gibberellic acid treatments ranged from 40 to 340 mg L⁻¹ for Asiatic lily ‘Yellow Cocotte’, 50 to 250 for gayfeather ‘Kobold’, and 50 to 150 for dahlia ‘Karma Serena’. Results varied within species in response to light and gibberellic acid. A significant interaction of light with gibberellic acid influenced mean flower number and flowering percentage for dahlia ‘Karma Serena’, while flowering percentage and flower diameter were influenced for Asiatic lily ‘Yellow Cocotte’. Effect of light was most significant on growth and flowering measurements, especially for gayfeather ‘Kobold’ and dahlia ‘Karma Serena’. For gayfeather ‘Kobold’, flowering occurred two weeks earlier under sole LED lighting than under other light treatments and no supplemental light. Although flowering occurred the earliest for dahlia ‘Karma Serena’ under no supplemental light, plants under light treatments had greater height, width, and shoot weight. Significant effects of gibberellic acid on growth and flowering measurements for dahlia ‘Karma Serena’ and Asiatic lily ‘Yellow Cocotte’ were observed for height, width, and flower number. Full article

(This article belongs to the Special Issue Advanced Greenhouse Horticulture: New Technologies and Cultivation Practices)

11 pages, 220 KiB

Open AccessArticle

Selection of Heat Tolerant Lettuce (Lactuca sativa L.) Cultivars Grown in Deep Water Culture and Their Marketability

by Sydney C. Holmes, Daniel E. Wells, Jeremy M. Pickens and Joseph M. Kemble

Horticulturae 2019, 5(3), 50; https://doi.org/10.3390/horticulturae5030050 - 13 Jul 2019

Cited by 32 | Viewed by 7386

Abstract

Lettuce is a cool season vegetable often produced in greenhouses and other protective structures to meet market demands. Greenhouses are being increasingly adopted in warm climate zones where excessive heat often leads to physiological disorders of lettuce, such as tipburn and premature bolting. [...] Read more.

Lettuce is a cool season vegetable often produced in greenhouses and other protective structures to meet market demands. Greenhouses are being increasingly adopted in warm climate zones where excessive heat often leads to physiological disorders of lettuce, such as tipburn and premature bolting. Greenhouse lettuce growers in warm climates need cultivar recommendations that can help improve production without ignoring marketability. In the current study, eighteen lettuce cultivars were grown in deep water culture and evaluated for growth, bolting, and tipburn in a greenhouse in Auburn, AL, starting on 30 June and 19 August 2016. Based on the severity of bolting and tipburn, nine cultivars were then selected and evaluated on 17 November 2016 for sensory attributes and marketability by 50 untrained consumer panelists. Cultivars ‘Adriana’, ‘Aerostar’, ‘Monte Carlo’, ‘Nevada’, ‘Parris Island’, ‘Salvius’, ‘Skyphos’, and ‘Sparx’ were selected as having higher heat tolerance than cultivars ‘Bambi’, ‘Buttercrunch’ ‘Coastal Star’, ‘Flashy Trout Back’, ‘Green Forest’, ‘Green Towers’, ‘Jericho’, ‘Magenta’, and ‘Truchas’. Higher crispness, lower bitterness, higher overall texture, and higher overall flavor each correlated to higher marketability, regardless of cultivar, but the strongest predictor of marketability was overall flavor. Overall flavor and overall texture were more strongly correlated to marketability than bitterness and crispness, respectively, suggesting that broader sensory categories may better capture human sensory perceptions of lettuce than narrower categories. Cultivars ‘Aerostar’, ‘Monte Carlo’, ‘Nevada’, ‘Parris Island’, ‘Rex’, ‘Salvius’, and ‘Sparx’ performed well in a hot greenhouse and were preferred by consumers. This step-wise experiment could be an adaptable tool for determining highest performing cultivars under any given production constraint, without ignoring marketability. Full article

(This article belongs to the Special Issue Advances in Knowledge of Hydroponic and Aquaponic Systems)

12 pages, 276 KiB

Open AccessFeature PaperArticle

Applications of Abscisic Acid and Increasing Concentrations of Calcium Affect the Partitioning of Mineral Nutrients between Tomato Leaf and Fruit Tissue

by T. Casey Barickman, Dean A. Kopsell and Carl E. Sams

Horticulturae 2019, 5(3), 49; https://doi.org/10.3390/horticulturae5030049 - 09 Jul 2019

Cited by 7 | Viewed by 3758

Abstract

This study examined how abscisic acid (ABA) and calcium (Ca) concentrations in nutrient solution affect concentrations of mineral nutrients in tomato leaves and fruit. Tomato plants were grown in a greenhouse at 25/20 °C (day/night) under a 16 h photoperiod. Plants were treated [...] Read more.

This study examined how abscisic acid (ABA) and calcium (Ca) concentrations in nutrient solution affect concentrations of mineral nutrients in tomato leaves and fruit. Tomato plants were grown in a greenhouse at 25/20 °C (day/night) under a 16 h photoperiod. Plants were treated with different concentrations of ABA and Ca. Calcium was applied via the irrigation lines at 60, 90, or 180 mg·L⁻¹. ABA was applied as a combination of foliar sprays and root applications. For foliar ABA applications, treatments consisted of deionized (DI) water control (0.0 mg·L⁻¹ ABA) or 500 mg·L⁻¹ ABA. For ABA root applications, treatments consisted of no ABA control (0.0 mg·L⁻¹ ABA) or 50 mg·L⁻¹ ABA applied via the irrigation lines. Results indicate that mineral nutrient concentrations in tomato leaf and fruit tissue varied in connection with each exogenous application of ABA. Variability in mineral nutrient concentration depended on if ABA was applied to the leaf or root tissue. Additionally, increasing Ca treatment concentrations either decreased or did not change mineral nutrients in tomato and fruit tissue. Thus, tomato plants react to acquiring mineral nutrients in numerous mechanisms and, depending on how the applications of exogenous ABA are applied, can have varying effects on these mechanisms. Full article

(This article belongs to the Special Issue Plant Growth Regulators for Improving the Yield and Quality of Horticultural Crops)

11 pages, 4772 KiB

Open AccessArticle

MALDI-TOF MS-Based Analysis of Seed Proteins from Catalogue Varieties of Solanum lycopersicum/Lycopersicon esculentum

by Michael Reeve

Horticulturae 2019, 5(3), 48; https://doi.org/10.3390/horticulturae5030048 - 26 Jun 2019

Cited by 3 | Viewed by 3801

Abstract

Matrix-assisted laser-desorption and ionization time-of-flight mass spectroscopy (MALDI-TOF MS) is a flexible technique for the analysis of protein-containing biological samples. Simple and inexpensive methods have previously been developed for MALDI-TOF MS sample preparation that are able to discriminate between Impatiens species that are [...] Read more.

Matrix-assisted laser-desorption and ionization time-of-flight mass spectroscopy (MALDI-TOF MS) is a flexible technique for the analysis of protein-containing biological samples. Simple and inexpensive methods have previously been developed for MALDI-TOF MS sample preparation that are able to discriminate between Impatiens species that are closely related and also between regional biotypes of the invasive weed Impatiens glandulifera (Himalayan balsam) with leaf material and also seed material. The current article investigates whether MALDI-TOF MS, through acid-soluble protein ‘fingerprinting’, can be used to analyze plant seeds that result from intensive commercial plant-breeding activity. As an initial proof-of-concept study, tomato seeds from eleven seed-catalogue varieties (F1 Pink Baby Plum, F1 Fantasio, F1 Lizzano, F1 Sungold, F1 Tumbler, Faworyt, Golden Sunrise, Hundreds and Thousands, Indigo Rose, Moneymaker, and Red Alert), listed as Solanum lycopersicum or under the synonym Lycopersicon esculentum were analyzed using MALDI-TOF MS. Whilst peak-rich and highly-reproducible spectra were obtained, with very high Bruker comparison scores and low MALDI-TOF MS variance, sample-preparation variance, and seed-to-seed variance, the spectral differences between varieties were only slightly greater than the above combined variances, indicating very close similarity between all eleven varieties studied. These results are discussed in comparison with those previously observed with the naturally-evolving invasive species I. glandulifera. Full article

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Horticulturae, Volume 5, Issue 3 (September 2019) – 18 articles

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