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Horticulturae, Volume 7, Issue 5 (May 2021) – 31 articles

Cover Story (view full-size image): New cultural techniques have been developed to improve the yield and raw material quality at harvest, and enhance the postharvest shelf life, by standardizing the growing system. The New Growing System (NGS®) is a closed recirculating system that has been designed for open fields and protected cultivations. The present contribution focuses on the investigation of the structural setting of the system and its potential performance in protected systems. A lab-scale pilot plant (LSPP) has been designed with NGS® technology and the technical aspects have been set up to have a standardized and reproducible growing system, usable for reliable experiments. The system has been proved to be adaptable for multiple re-growth of plants, avoiding replanting from seedlings. View this paper
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Article
Heat Treatment in Two Tomato Cultivars: A Study of the Effect on Physiological and Growth Recovery
Horticulturae 2021, 7(5), 119; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050119 - 20 May 2021
Cited by 1 | Viewed by 914
Abstract
High temperature (HT) significantly affects crop physiological traits and reduces productivity in plants. To increase yields as well as survival of crops under HT, developing heat-tolerant plants is one of the main targets in crop breeding programs. The present study attempted to investigate [...] Read more.
High temperature (HT) significantly affects crop physiological traits and reduces productivity in plants. To increase yields as well as survival of crops under HT, developing heat-tolerant plants is one of the main targets in crop breeding programs. The present study attempted to investigate the linkage of the heat tolerance between the seedling and reproductive growth stages of tomato cultivars ’Dafnis‘ and ’Minichal.’ This research was undertaken to evaluate heat tolerance under two experimental designs such as screening at seedling stage and screening from reproductive traits in greenhouses. Survival rate and physiological responses in seedlings of tomatoes with 4-5 true leaves were estimated under HT (40 °C, RH 70%, day/night, respectively) and under two control and HT greenhouse conditions (day time 28 °C and 40 °C, respectively). Heat stress significantly affected physiological–chemical (photosynthesis, electrolyte conductivity, proline) and vegetative parameters (plant height, shoot fresh weight, root fresh weight) in all tomato seedlings. The findings revealed that regardless of tomato cultivars the photosynthesis, chlorophyll, total proline and electrical conductivity parameters were varied in seedlings during the heat stress period. The heat tolerance rate of tomatoes in the seedling stage might not always be associated with reproductive parameters. HT reduced fruit parameters such as fruit weight (31.9%), fruit length (14.1%), fruit diameter (19.1%), and fruit hardness (9.1%) compared to NT under HT in heat-susceptible tomato cultivar ‘Dafnis’, while in heat-tolerant cultivar ‘Minichal’ fruit length (7.1%) and fruit diameter (12.1%) was decreased by the effects of HT, but on the contrary fruit weight (3.6%) and fruit hardness (8.3%) were increased. In conclusion, screening and selection for tomatoes should be evaluated at the vegetative and reproductive stages with consideration of reproductive parameters. Full article
(This article belongs to the Special Issue Factors Affecting the Quality and Shelf Life of Horticultural Crops)
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Article
Optimization of Different Factors for Initiation of Somatic Embryogenesis in Suspension Cultures in Sandalwood (Santalum album L.)
Horticulturae 2021, 7(5), 118; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050118 - 19 May 2021
Cited by 1 | Viewed by 404
Abstract
Santalum album (L.) is a prized tropical tree species of high therapeutic and industrial importance. The wood of these naturally grown plants is extensively harvested to acquire therapeutically important metabolite santalol and be used for additional functions such as in wood statuette industries. [...] Read more.
Santalum album (L.) is a prized tropical tree species of high therapeutic and industrial importance. The wood of these naturally grown plants is extensively harvested to acquire therapeutically important metabolite santalol and be used for additional functions such as in wood statuette industries. Due to high demand, it is crucial to maintain a sufficient plant population. An easy protocol for establishing cell suspension culture initiated from the loose embryogenic callus mass of sandalwood was realized by shifting 6–8-week-old morphogenic calli acquired from the mature embryonic axis and cotyledon explant cultures in fluid media. The asynchronous embryogenic cultures were sloughed with clumps of flourishing cell clumps and embryos of various progressive phases along with diffident non-embryogenic tissues. The frequency of embryo proliferation was evidenced to determinethe expansion pace of embryogenic masses under diverse conditions. The intonation of initiation and creation of cell suspension was under the directive of the influence of exogenous plant growth regulators amended in the nutrient medium at different concentrations and combinations. Maximum relative growth rate (386%) and clumps/embryoids in elevated integers (321.44) were accomplished on MS nutrient medium fortified with 2.0 mg L−1 2,4-D in association with 0.5 mg L−1 BA and 30.0 g L−1 sucrose raised from mature embryonic axis-derived calli. Plantlet regeneration in higher frequency (84.43%) was evidenced on MS medium amended with 1.0 mg L−1 each of TDZ and GA3 in conjunction with 0.5 mg L−1 NAA and 20.0 g L−1 sucrose. Mature embryonic axis-derived calli were found to be constantly better than mature cotyledon-derived calli for raising profitable and reproducible cell suspension cultures. Regenerants displayed normal growth and morphology and were founded successfully in the external environment after hardening. Full article
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Article
CaHSP18.1a, a Small Heat Shock Protein from Pepper (Capsicum annuum L.), Positively Responds to Heat, Drought, and Salt Tolerance
Horticulturae 2021, 7(5), 117; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050117 - 18 May 2021
Viewed by 394
Abstract
Pepper is a thermophilic crop, shallow-rooted plant that is often severely affected by abiotic stresses such as heat, salt, and drought. The growth and development of pepper is seriously affected by adverse stresses, resulting in decreases in the yield and quality of pepper [...] Read more.
Pepper is a thermophilic crop, shallow-rooted plant that is often severely affected by abiotic stresses such as heat, salt, and drought. The growth and development of pepper is seriously affected by adverse stresses, resulting in decreases in the yield and quality of pepper crops. Small heat shock proteins (s HSPs) play a crucial role in protecting plant cells against various stresses. A previous study in our laboratory showed that the expression level of CaHSP18.1a was highly induced by heat stress, but the function and mechanism of CaHSP18.1a responding to abiotic stresses is not clear. In this study, we first analyzed the expression of CaHSP18.1a in the thermo-sensitive B6 line and thermo-tolerant R9 line and demonstrated that the transcription of CaHSP18.1a was strongly induced by heat stress, salt, and drought stress in both R9 and B6, and that the response is more intense and earlier in the R9 line. In the R9 line, the silencing of CaHSP18.1a decreased resistance to heat, drought, and salt stresses. The silencing of CaHSP18.1a resulted in significant increases in relative electrolyte leakage (REL) and malonaldehyde (MDA) contents, while total chlorophyll content decreased under heat, salt, and drought stresses. Overexpression analyses of CaHSP18.1a in transgenic Arabidopsis further confirmed that CaHSP18.1a functions positively in resistance to heat, drought, and salt stresses. The transgenic Arabidopsis had higherchlorophyll content and activities of superoxide dismutase, catalase, and ascorbate peroxidase than the wild type (WT). However, the relative conductivity and MDA content were decreased in transgenic Arabidopsis compared to the wild type (WT). We further showed that the CaHSP18.1a protein is localized to the cell membrane. These results indicate CaHSP18.1a may act as a positive regulator of responses to abiotic stresses. Full article
(This article belongs to the Special Issue Advances in Molecular Breeding of Vegetable Crops)
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Article
Cowpea Ecophysiological Responses to Accumulated Water Deficiency during the Reproductive Phase in Northeastern Pará, Brazil
Horticulturae 2021, 7(5), 116; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050116 - 18 May 2021
Viewed by 346
Abstract
Cowpea (Vigna unguiculata (L.) Walp.) is a leguminous species widely cultivated in northern and northeastern Brazil. In the state of Pará, this crop still has low productivity due to several factors, such as low soil fertility and climatic adversity, especially the water [...] Read more.
Cowpea (Vigna unguiculata (L.) Walp.) is a leguminous species widely cultivated in northern and northeastern Brazil. In the state of Pará, this crop still has low productivity due to several factors, such as low soil fertility and climatic adversity, especially the water deficiency. Therefore, the present study aimed at evaluating the physiological parameters and the productivity of cowpea plants under different water depths. The experiment was conducted in Castanhal/Pará between 2015 and 2016. A randomized block design was applied with six replications and four treatments, represented by the replacement of 100%, 50%, 25% and 0% of the water lost during crop evapotranspiration (ETc), starting from the reproductive stage. The rates of net photosynthesis (A), stomatal conductance (gs), leaf transpiration (Eleaf), substomatal CO2 concentration (Ci), leaf temperature (Tleaf) and leaf water potential (Ψw) were determined in four measurements at the R5, R7, R8 and R9 phenological stages. Cowpea was sensitive to the water availability in the soil, showing a significant difference between treatments for physiological variables and productivity. Upon reaching a Ψw equal to −0.88 MPa, the studied variables showed important changes, which allows establishing this value as a threshold for the crop regarding water stress under such experimental conditions. The different water levels in the soil directly influenced productivity for both years, indicating that the proper water supply leads to better crop growth and development, increasing productivity. Full article
(This article belongs to the Special Issue Drought Stress in Horticultural Plants)
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Review
Phenotyping Brown Rot Susceptibility in Stone Fruit: A Literature Review with Emphasis on Peach
Horticulturae 2021, 7(5), 115; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050115 - 17 May 2021
Viewed by 515
Abstract
Plant disease phenotyping methodologies can vary considerably among testers and often suffer from shortcomings in their procedures and applications. This has been an important challenge in resistance breeding to brown rot, one of the most severe pre-and postharvest stone fruit diseases caused by [...] Read more.
Plant disease phenotyping methodologies can vary considerably among testers and often suffer from shortcomings in their procedures and applications. This has been an important challenge in resistance breeding to brown rot, one of the most severe pre-and postharvest stone fruit diseases caused by Monilinia spp. Literature about methodologies for evaluating stone fruit susceptibility to brown rot is abundant but displays significant variations across the described approaches, limiting the ability to compare results from different studies. This is despite the fact that authors largely agree on the main factors influencing brown rot development, such as Monilinia inocula, environmental conditions, cultivars, fruit stage, and management practices. The present review first discusses ways to control or at least account for major factors affecting brown rot phenotyping studies. The second section describes in detail the different steps of fruit infection assays, comparing different protocols available in the literature with the objective of highlighting best practices and further improvement of phenotyping for brown rot susceptibility. Finally, experimental results from multi-year evaluation trials are also reported, highlighting year-to-year variability and exploring correlations of evaluation outcomes among years and assay types, suggesting that choice of phenotyping methodology must be carefully considered in breeding programs. Full article
(This article belongs to the Special Issue Feature Papers in Horticulturae Ⅱ)
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Article
Phenotypic Characterization and Differential Gene Expression Analysis Reveal That Dwarf Mutant dwf Dwarfism Is Associated with Gibberellin in Eggplant
Horticulturae 2021, 7(5), 114; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050114 - 16 May 2021
Cited by 1 | Viewed by 526
Abstract
Dwarfism is a desirable trait in eggplant breeding, as it confers higher lodging resistance and allows simplified management and harvest. However, a few dwarf mutants have been reported, and the molecular mechanism underlying dwarfism in eggplant is completely unknown. Here, we report a [...] Read more.
Dwarfism is a desirable trait in eggplant breeding, as it confers higher lodging resistance and allows simplified management and harvest. However, a few dwarf mutants have been reported, and the molecular mechanism underlying dwarfism in eggplant is completely unknown. Here, we report a dwarf mutant (dwf) isolated from an ethyl methyl sulfonate (EMS)-induced mutant library. The hypocotyl length, plant height, and length of internode cells of dwf were significantly decreased compared to those of the wild-type parent ‘14-345’ (WT). Differential gene expression analysis revealed that GA-related genes, including GA2ox and DELLA, were up-regulated whereas the gibberellin (GA3) content decreased in dwf. Moreover, exogenous GA3 treatment significantly increased the relative growth rate of dwf compared to WT, further indicating the important roles of GA in regulating the dwarf phenotype of dwf. Collectively, our findings shed light on GA-mediated dwarfism in dwf plants and offer a good germplasm that could be used for eggplant dwarfism breeding in the future. Full article
(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))
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Article
Bruise Damage and Quality Changes in Impact-Bruised, Stored Tomatoes
Horticulturae 2021, 7(5), 113; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050113 - 16 May 2021
Cited by 2 | Viewed by 512
Abstract
This study examined three main possible effects (impact, storage temperature, and duration) that cause and extend the level of bruising and other quality attributes contributing to the deterioration of tomatoes. The impact threshold level required to cause bruising was conducted by subjecting tomato [...] Read more.
This study examined three main possible effects (impact, storage temperature, and duration) that cause and extend the level of bruising and other quality attributes contributing to the deterioration of tomatoes. The impact threshold level required to cause bruising was conducted by subjecting tomato samples to a steel ball with a known mass from different drop heights (20, 40, and 60 cm). The samples were then divided and stored at 10 and 22 °C for 10 days for the further analysis of bruise area and any physiological, chemical, and nutritional changes at two day intervals. Six prediction models were constructed for the bruised area and other quality attribute changes of the tomato. Storage time, bruise area, weight loss, redness, total color change, color index, total soluble solids, and pigments content (lycopene and carotenoids) showed a significant (p < 0.05) increase with the increase of drop height (impact level) and storage temperature. After 10 days of storage, high drop impact and storage at 22 °C generated a higher reduction in firmness, lightness, yellowness, and hue° (color purity). Additionally, regression model findings showed the significant effect of storage duration, storage temperature, and drop height on the measured variables (bruise area, weight loss, firmness, redness, total soluble solids, and lycopene) at a 5% probability level with a determination coefficient (R2) ranging from 0.76 to 0.95. Bruising and other quality attributes could be reduced by reducing the temperature during storage. This study can help tomato transporters, handlers, and suppliers to understand the mechanism of bruising occurrence and how to reduce it. Full article
(This article belongs to the Section Postharvest Biology, Quality, Safety, and Technology)
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Article
Interactive Impacts of Temperature and Elevated CO2 on Basil (Ocimum basilicum L.) Root and Shoot Morphology and Growth
Horticulturae 2021, 7(5), 112; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050112 - 14 May 2021
Cited by 1 | Viewed by 563
Abstract
Recent evidence suggests that the effects of temperature significantly affect the growth and development of basil plants with detrimental impacts on yield. The current research investigated the interactive effects of varying temperature and CO2 levels on the shoot and root morphology and [...] Read more.
Recent evidence suggests that the effects of temperature significantly affect the growth and development of basil plants with detrimental impacts on yield. The current research investigated the interactive effects of varying temperature and CO2 levels on the shoot and root morphology and growth of early and late-season basil plants. Basil plants were subjected to control (30/22 °C), low (20/12 °C), and high (38/30 °C) temperature under ambient (420 μL L−1) and elevated (720 μL L−1) CO2 concentrations. Decreasing the temperature to 20/12 °C caused more adverse effects on the morphological traits of the early-season basil. Relative to the control treatments, low- and high-temperature stresses decreased 71 and 14% in marketable fresh mass, respectively. Basil exhibited an increase in plant height, node and branch numbers, specific leaf area, anthocyanin and nitrogen balance index, root tips, and root crossings when subjected to high-temperature stress. Furthermore, elevated CO2 affected many morphological features compared to ambient CO2 concentrations. The findings of this study suggest that varying the growth temperature of basil plants would more significantly impact the shoot and root morphologies and growth rates of basil than increasing the CO2 concentrations, which ameliorated the adverse impacts of temperature stress. Full article
(This article belongs to the Special Issue Plant Physiology under Abiotic Stresses)
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Article
Plant Production and Leaf Anatomy of Mertensia maritima (L.) Gray: Comparison of In Vitro Culture Methods to Improve Acclimatization
Horticulturae 2021, 7(5), 111; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050111 - 13 May 2021
Viewed by 466
Abstract
Mertensia maritima is a commercially interesting herb with edible leaves and flowers, characterized by oyster flavor and taste. Plant propagation and traditional cultivation are challenging for this species. Therefore, the main purpose of the present study was to establish successful protocols aimed at [...] Read more.
Mertensia maritima is a commercially interesting herb with edible leaves and flowers, characterized by oyster flavor and taste. Plant propagation and traditional cultivation are challenging for this species. Therefore, the main purpose of the present study was to establish successful protocols aimed at ensuring oyster plant shoot propagation, rooting and in vivo acclimatization. Both micropropagation and rooting were tested, comparing the traditional in vitro solid substrate in jar vs. the liquid culture in a temporary immersion system (TIS) bioreactor (Plantform™). A Murashige and Skoog (MS) medium added with 4-μM thidiazuron (TDZ) and 1-μM α-naphthaleneacetic acid (NAA) was employed for micropropagation, while a half-strength MS medium supplemented with 4-μM indole−3-butyric acid (IBA) was used for rooting. Different acclimatization conditions in the greenhouse or in growth chamber were tested. Morphometric and microscopical analyses were performed on the oyster plant leaves at the propagation, rooting and acclimatization stages both in a jar and in a TIS. Micropropagation in a TIS allowed to obtain large shoots, while a great number of shoots was observed in the jar. M. maritima shoots rooted in TIS produced more developed roots, leaves with more developed waxy glands and well-formed stomata; moreover, the plants coming from the TIS showed the best acclimatization performances. Full article
(This article belongs to the Special Issue Application of Tissue Culture to Horticulture)
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Article
Comparative Transcriptome Analysis Reveals Different Low-Nitrogen-Responsive Genes in Pepper Cultivars
Horticulturae 2021, 7(5), 110; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050110 - 13 May 2021
Viewed by 506
Abstract
The molecular mechanisms underlying the variation in N-use efficiency (NUE) in pepper (Capsicum annuum L.) genotypes are poorly understood. In this work, two genotypes (750-1, low-N tolerant; ZCFB, low-N sensitive) with contrasting low-N tolerance were selected from 100 pepper cultivars on the [...] Read more.
The molecular mechanisms underlying the variation in N-use efficiency (NUE) in pepper (Capsicum annuum L.) genotypes are poorly understood. In this work, two genotypes (750-1, low-N tolerant; ZCFB, low-N sensitive) with contrasting low-N tolerance were selected from 100 pepper cultivars on the basis of their relative leaf areas, shoot dry weights, root dry weights, and plant dry weights at the seedling stage. Subsequently, using RNA-Seq, the transcriptome of these two pepper genotypes under N starvation for 28 days was analyzed. We detected 2621/2470 and 3936/4218 different expressed genes (DEGs) in the leaves/roots of 750-1 and ZCFB, respectively. The changes in the expression of basic N metabolism genes were similar between 750-1 and ZCFB. However, different DEGs not directly involved in N metabolism were identified between the 750-1 and ZCFB cultivars. In 750-1, 110 unique DEGs were detected in the leaves, of which 103 were down-regulated, including genes associated with protein metabolism, photosynthesis, secondary metabolism, cell wall metabolism, stress response, and disease resistance. In ZCFB, 142 unique DEGs were detected in the roots, of which 117 were up-regulated, resulting in enhancement of processes such as protein degradation, secondary metabolites synthesis, lipid metabolism, endocytosis, the tricarboxylic acid cycle (TCA), transcriptional regulation, stress response, and disease resistance. Our results not only facilitate an understanding of the different regulatory process in low-N-tolerant and low-N-sensitive pepper cultivars, but also provide abundant candidate genes for improving the low-N tolerance of pepper cultivars. Full article
(This article belongs to the Special Issue Advances in Molecular Breeding of Vegetable Crops)
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Article
Adaptive Morphophysiological Features of Neottia ovata (Orchidaceae) Contributing to Its Natural Colonization on Fly Ash Deposits
Horticulturae 2021, 7(5), 109; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050109 - 11 May 2021
Viewed by 511
Abstract
In previous decades, some species of the Orchidaceae family have been found growing in man-made habitats. Neottia ovata is one of the most widespread orchids in Europe, however it is quite rare in Russia and is included in several regional Red Data Books. [...] Read more.
In previous decades, some species of the Orchidaceae family have been found growing in man-made habitats. Neottia ovata is one of the most widespread orchids in Europe, however it is quite rare in Russia and is included in several regional Red Data Books. The purpose of this study was to compare the chemical composition and morphophysiological parameters of N. ovata from two forest communities of the Middle Urals, Russia: natural and transformed (fly ash dump of Verkhnetagil’skaya Thermal Power Station) for determining orchid adaptive features. The content of most of the studied metals in the underground parts (rhizome + roots) of N. ovata was considerably higher than in the leaves, which diminished the harmful effect of toxic metals on the aboveground organs. The adaptive changes in the leaf mesostructure of N. ovata such as an increase in epidermis thickness, the number of chloroplasts in the cell, and the internal assimilating surface were found for the first time. The orchids from the fly ash deposits were characterized by a higher content of chlorophyll b and carotenoids than plants from the natural forest community that evidenced the compensatory response on the decrease in chlorophyll a. The ability of N. ovata from the transformed habitat to maintain a relatively favorable water balance and stable assimilation indexes further contribute to its high viability. The study of orchid adaptive responses to unfavorable factors is necessary for their successful naturalization and introduction into a new environment. Full article
(This article belongs to the Special Issue Study of the Influence of Abiotic and Biotic Stress Factors on Plants)
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Article
Detecting Maturity in Fresh Lycium barbarum L. Fruit Using Color Information
Horticulturae 2021, 7(5), 108; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050108 - 11 May 2021
Viewed by 411
Abstract
The accurate quantitative maturity detection of fresh Lycium barbarum L. (L. barbarum) fruit is the key to determine whether fruit are suitable for harvesting or not and can also be helpful to improve the quality of post-harvest processing. To achieve this [...] Read more.
The accurate quantitative maturity detection of fresh Lycium barbarum L. (L. barbarum) fruit is the key to determine whether fruit are suitable for harvesting or not and can also be helpful to improve the quality of post-harvest processing. To achieve this goal, abnormal samples were eliminated by the Mahalanobis Distance (MD), and nine components (i.e., R, G, B, H, S, V, L, a, and b) of the ripe fruit, half-ripe fruit, and unripe fruit were extracted, firstly. Then, significant component combinations of the three fruits beneficial to the extraction of their areas were determined. Through binary processing, morphology processing, and other image processing methods, a quantitative maturity detection model of fruit was established based on the support vector machine (SVM) model. On this basis, field experiments were conducted to verify and compare the relationship between the prediction results of the model and the picking forces of fruit. Field experiments showed that the accuracies of both the training set and prediction set were 100% and the prediction results of the model were consistent with the picking forces of fruit. Findings provided a theoretical basis for the accurate quantitative maturity detection of fresh L. barbarum fruit. Full article
(This article belongs to the Section Fruit Production Systems)
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Review
Biochemical, Physiological, and Molecular Aspects of Ornamental Plants Adaptation to Deficit Irrigation
Horticulturae 2021, 7(5), 107; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050107 - 10 May 2021
Cited by 3 | Viewed by 454
Abstract
There is increasing concern regarding global warming and its severe impact on the farming sector and food security. Incidences of extreme weather conditions are becoming more and more frequent, posing plants to stressful conditions, such as flooding, drought, heat, or frost etc. Especially [...] Read more.
There is increasing concern regarding global warming and its severe impact on the farming sector and food security. Incidences of extreme weather conditions are becoming more and more frequent, posing plants to stressful conditions, such as flooding, drought, heat, or frost etc. Especially for arid lands, there is a tug-of-war between keeping high crop yields and increasing water use efficiency of limited water resources. This difficult task can be achieved through the selection of tolerant water stress species or by increasing the tolerance of sensitive species. In this scenario, it is important to understand the response of plants to water stress. So far, the response of staple foods and vegetable crops to deficit irrigation is well studied. However, there is lack of literature regarding the responses of ornamental plants to water stress conditions. Considering the importance of this ever-growing sector for the agricultural sector, this review aims to reveal the defense mechanisms and the involved morpho-physiological, biochemical, and molecular changes in ornamental plant’s responses to deficit irrigation. Full article
(This article belongs to the Special Issue Drought Stress in Horticultural Plants)
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Article
Effects of Hydrogen Peroxide on Organically Fertilized Hydroponic Lettuce (Lactuca sativa L.)
Horticulturae 2021, 7(5), 106; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050106 - 10 May 2021
Viewed by 493
Abstract
Hydroponic production typically uses conventional fertilizers, but information is lacking on the use of organic hydroponic fertilizers. Development of microbial communities and biofilm that can reduce dissolved oxygen availability is a difficulty with organic hydroponics. One potential solution is the use of hydrogen [...] Read more.
Hydroponic production typically uses conventional fertilizers, but information is lacking on the use of organic hydroponic fertilizers. Development of microbial communities and biofilm that can reduce dissolved oxygen availability is a difficulty with organic hydroponics. One potential solution is the use of hydrogen peroxide (H2O2) which can reduce microbial populations and decompose to form oxygen. However, information is lacking on the impact of hydrogen peroxide on hydroponic crop performance. The aim of this study was to determine the effects of H2O2 concentrations in deep water culture hydroponics by assessing how it affects plant size and yield in lettuce (Lactuca sativa L.) “Rouxai”. In this experiment, three H2O2 treatments, namely the application of 0, 37.5 or 75 mg/L H2O2 to 4 L aerated hydroponic containers with either conventional or organic fertilizer, were compared. The containers had either fish-based organic fertilizer (4-4-1, N-P2O5-K2O) or inorganic mineral based conventional nutrient solution (21-5-20, N-P2O5-K2O), both applied at 150 mg/L N. Three replicates of each H2O2 treatment–fertilizer combination were prepared resulting in a total of eighteen mini hydroponic containers each with one head of lettuce. There were two growth cycles: fall 2018 and spring 2019. When added to conventional fertilizers, both 37.5 mg/L and 75 mg/L of H2O2 led to stunted growth or death of lettuce plants. However, when 37.5 mg/L of H2O2 was applied to organic fertilizers, the lettuce yield nearly matched that of the conventionally fertilized control, demonstrating that the application of H2O2 has the potential to make organic hydroponic fertilization a more viable method in the future. Full article
(This article belongs to the Special Issue Hydroponics in Vegetable Production)
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Communication
An Optimized Protocol for In Vitro Indirect Shoot Organogenesis of Impala Bronzovaya and Zanzibar Green Ricinus communis L. Varieties
Horticulturae 2021, 7(5), 105; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050105 - 09 May 2021
Viewed by 560
Abstract
The castor bean is an important industrial and ornamental crop. In the industry, it is used as a source of castor oil. Moreover, it has a large potential as a feed crop, because the seeds contain a high amount of protein. A main [...] Read more.
The castor bean is an important industrial and ornamental crop. In the industry, it is used as a source of castor oil. Moreover, it has a large potential as a feed crop, because the seeds contain a high amount of protein. A main problem with castor bean use is the presence of toxins in the plants. Today, detoxification is carried out using various approaches, including biotechnological methods such as CRISPR/Cas9 technology. A successful application of these methods requires the availability of an efficient in vitro protocol for callus induction and shoot organogenesis. We present the results of in vitro condition optimization for two castor bean varieties (Impala Bronzovaya and Zanzibar Green). Eight different Murashige–Skoog (MS) culture media characterized by different plant growth regulator (PGR) combinations, as well as explant types (hypocotyls, cotyledonous leaves, and cotyledon petioles), were tested. The highest frequency of shoot organogenesis and average number per explant were observed during the cultivation of cotyledon petioles in both varieties on the Murashige and Skoog culture medium (MS) containing 1 or 2 mg/L of zeatin in combination with 0.1 mg/L of 3-indoleacetic acid (IAA). An optimized protocol for in vitro callus induction and shoot organogenesis may be used for biotechnological applications to obtain toxin-free castor bean, as well as Ricinus communis L. plants, with new ornamental traits and their combinations. Full article
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Article
Genetic Diversity and Population Differentiation of Pinus koraiensis in China
Horticulturae 2021, 7(5), 104; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050104 - 09 May 2021
Viewed by 441
Abstract
Pinus koraiensis is a well-known precious tree species in East Asia with high economic, ornamental and ecological value. More than fifty percent of the P. koraiensis forests in the world are distributed in northeast China, a region with abundant germplasm resources. However, these [...] Read more.
Pinus koraiensis is a well-known precious tree species in East Asia with high economic, ornamental and ecological value. More than fifty percent of the P. koraiensis forests in the world are distributed in northeast China, a region with abundant germplasm resources. However, these natural P. koraiensis sources are in danger of genetic erosion caused by continuous climate changes, natural disturbances such as wildfire and frequent human activity. Little work has been conducted on the population genetic structure and genetic differentiation of P. koraiensis in China because of the lack of genetic information. In this study, 480 P. koraiensis individuals from 16 natural populations were sampled and genotyped. Fifteen polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers were used to evaluate genetic diversity, population structure and differentiation in P. koraiensis. Analysis of molecular variance (AMOVA) of the EST-SSR marker data showed that 33% of the total genetic variation was among populations and 67% was within populations. A high level of genetic diversity was found across the P. koraiensis populations, and the highest levels of genetic diversity were found in HH, ZH, LS and TL populations. Moreover, pairwise Fst values revealed significant genetic differentiation among populations (mean Fst = 0.177). According to the results of the STRUCTURE and Neighbor-joining (NJ) tree analyses and principal component analysis (PCA), the studied geographical populations cluster into two genetic clusters: cluster 1 from Xiaoxinganling Mountains and cluster 2 from Changbaishan Mountains. These results are consistent with the geographical distributions of the populations. The results provide new genetic information for future genome-wide association studies (GWAS), marker-assisted selection (MAS) and genomic selection (GS) in natural P. koraiensis breeding programs and can aid the development of conservation and management strategies for this valuable conifer species. Full article
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Article
Artificial Intelligence and Novel Sensing Technologies for Assessing Downy Mildew in Grapevine
Horticulturae 2021, 7(5), 103; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050103 - 08 May 2021
Viewed by 547
Abstract
Plant diseases and pests cause a large loss of world agricultural production. Downy mildew is a major disease in grapevine. Conventional techniques for plant diseases evaluations are time-consuming and require expert personnel. This work investigates novel sensing technologies and artificial intelligence applications for [...] Read more.
Plant diseases and pests cause a large loss of world agricultural production. Downy mildew is a major disease in grapevine. Conventional techniques for plant diseases evaluations are time-consuming and require expert personnel. This work investigates novel sensing technologies and artificial intelligence applications for assessing downy mildew in grapevine under laboratory conditions. In our methodology, machine vision is applied to assess downy mildew sporulation, while hyperspectral imaging is used to explore its potential capability towards early detection of this disease. Image analysis applied to RGB leaf disc images is used to estimate downy mildew (Plamopara viticola) severity in grapevine (Vitis vinifera L. cv Tempranillo). A determination coefficient (R2) of 0.76 ** and a root mean square error (RMSE) of 20.53% are observed in the correlation between downy mildew severity by computer vision and expert’s visual assessment. Furthermore, an accuracy of 81% is achieved to detect downy mildew early using hyperspectral images. These results indicate that non-invasive sensing technologies and computer vision can be applied for assessing and quantify sporulation of downy mildew in grapevine leaves. The severity of this key disease is evaluated in grapevine under laboratory conditions. In conclusion, computer vision, hyperspectral imaging and machine learning could be applied for important disease detection in grapevine. Full article
(This article belongs to the Special Issue Advances in Viticulture Production)
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Article
Evaluation of Air Temperature, Photoperiod and Light Intensity Conditions to Produce Cucumber Scions and Rootstocks in a Plant Factory with Artificial Lighting
Horticulturae 2021, 7(5), 102; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050102 - 08 May 2021
Viewed by 509
Abstract
Air temperature and light conditions are important factors not only to produce high-quality seedlings but also to promote energy efficiency in a plant factory with artificial lighting. In this study, we conducted two experiments in order to investigate the favorable conditions of air [...] Read more.
Air temperature and light conditions are important factors not only to produce high-quality seedlings but also to promote energy efficiency in a plant factory with artificial lighting. In this study, we conducted two experiments in order to investigate the favorable conditions of air temperature, light intensity and photoperiod for the production of cucumber scions and rootstocks in a plant factory with artificial lighting. Cucumber scions and rootstocks were cultivated in two combined treatments: the combination of three different levels of difference between the day and night temperature (DIF), 25/20, 26/18 and 27/16 °C and five different light intensity conditions of photosynthetic photon flux, 50, 100, 150, 200 and 250 μmol·m−2·s−1 was set for the first experiment, and the combination of three different photoperiod conditions, 12, 16 and 20 h·d−1 and five different light intensity conditions, 50, 100, 150, 200 and 250 μmol·m−2·s−1 was set for the second experiment. In the air temperature and light intensity treatments, the hypocotyl elongation of cucumber scions and rootstocks was affected more largely by light intensity than DIF. The highest DIF treatment (27/16 °C) affected negatively on the accumulation of dry mass. On the contrary, the smallest DIF treatment (25/20 °C) was favorable for seedling growth due to lesser stress by rapid change of air temperature between photo- and dark-period. In the photoperiod and light intensity treatments, an increased DLI (daily light integral) promoted the growth of scions and rootstocks. Under the same DLI condition, the growth of scions and rootstocks increased with increasing photoperiod and decreasing light intensity. In both of experiments, while the dry weight increased with increasing the light intensity, the light use efficiencies were reduced by increasing the light intensity. Considering the growth and quality of seedlings and energy efficiency, the optimal environment conditions were represented by 25/20 °C of air temperature, 150 μmol·m−2·s−1 of light intensity and 16 h·d−1 of photoperiod. Full article
(This article belongs to the Special Issue Smart Farming Techniques for Protected Horticulture Facilities)
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Article
In-Vivo In-Vitro Screening of Ocimum basilicum L. Ecotypes with Differential UV-B Radiation Sensitivity
Horticulturae 2021, 7(5), 101; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050101 - 07 May 2021
Viewed by 482
Abstract
Elevated UV-B radiation (UV-B) has been previously reported to affect plant development, physiology, and promote the biosynthesis of UV-absorbing compounds. Sweet basil (Ocimum basilicum L.) is an aromatic herb, widely cultivated worldwide for its use in the food, pharmaceuticals, and cosmetics industry. [...] Read more.
Elevated UV-B radiation (UV-B) has been previously reported to affect plant development, physiology, and promote the biosynthesis of UV-absorbing compounds. Sweet basil (Ocimum basilicum L.) is an aromatic herb, widely cultivated worldwide for its use in the food, pharmaceuticals, and cosmetics industry. This species exhibits high diversity among different ecotypes based on their geographical locations. There has been little research on intra-specific photosynthetic and metabolic differences in UV-B tolerance across ecotypes from different geographical areas. This study evaluated the protection responses to high UV-B radiation of nine O. basilicum accessions with different geographic origins. Specifically, the changes in chlorophyll a fluorescence parameters and the leaf rosmarinic acid (RA) compound were assessed using an “in vivo-vitro system” in a closed-type plant production system. Our results revealed a significant variation in UV-B protection mechanisms among accessions when plants were treated with high UV-B doses. The accumulation of RA increased significantly by UV-B light treatment in OCI142, OCI148, OCI30, OCI160, and OCI102, with the highest concentration measured in OCI160 plants. This ecotype showed the highest value of the Fv/Fm ratio, 0.70, after 48 h. Recovery of leaf functionality was more rapid in OCI160 than in other sweet basil accessions, which may indicate better photosynthetic capacity associated with enhanced biosynthesis of UV absorbing compounds. This study shows that the biosynthesis of the UV-absorbing compound (RA) represents an effective mechanism to reduce the photoinhibitory and photooxidative damage caused by high UV stress. Full article
(This article belongs to the Special Issue Application of Tissue Culture to Horticulture)
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Article
Effects of Vermicompost Leachate versus Inorganic Fertilizer on Morphology and Microbial Traits in the Early Development Growth Stage in Mint (Mentha spicata L.) And Rosemary (Rosmarinus officinalis L.) Plants under Closed Hydroponic System
Horticulturae 2021, 7(5), 100; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050100 - 06 May 2021
Viewed by 388
Abstract
The objective of this study was to compare the morphology of M. spicata and R. officinalis plants, and the relative abundance quantification, colony-forming units, ribotypes, and biofilm former bacteria under an inorganic fertilizer and the use of vermicompost leachate in the rhizosphere under [...] Read more.
The objective of this study was to compare the morphology of M. spicata and R. officinalis plants, and the relative abundance quantification, colony-forming units, ribotypes, and biofilm former bacteria under an inorganic fertilizer and the use of vermicompost leachate in the rhizosphere under a closed hydroponic system. In mint (Mentha spicata) plants treated with the vermicompost leachate, growth increase was determined mainly in root length from an average of 38 cm in plants under inorganic fertilizer to 74 cm under vermicompost leachate. In rosemary (Rosmarinus officinalis), no changes were determined between the two treatments. There were differences in the compositions of microbial communities: For R. officinalis, eight ribotypes were identified, seven for inorganic fertilizer and four for vermicompost leachate. For M. spicata, eight ribotypes were identified, three of them exclusive to vermicompost leachate. However, no changes were observed in microbial communities between the two treatments. Otherwise, some changes were observed in the compositions of these communities over time. In both cases, the main found phylum was Firmicutes, with 60% for R. officinalis and 80% for M. spicata represented by the Bacillus genus. In conclusion, the use of vermicompost leachate under the hydroponic system is a viable alternative to achieve an increase in the production of M. spicata, and for both plants (mint and rosemary), the quality of the product and the microbial communities that inhabited them remained unaltered. Full article
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Article
Rootstock–Scion Hydraulic Balance Influenced Scion Vigor and Yield Efficiency of Malus domestica cv. Honeycrisp on Eight Rootstocks
Horticulturae 2021, 7(5), 99; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050099 - 03 May 2021
Viewed by 617
Abstract
Rootstocks with internal hydraulic limitations can effectively restrict scion growth, influence crop load, and improve yield efficiency in apple production. The characteristics of xylem vessels in rootstock and scion play essential roles in determining the hydraulic properties of the grafted tree; however, much [...] Read more.
Rootstocks with internal hydraulic limitations can effectively restrict scion growth, influence crop load, and improve yield efficiency in apple production. The characteristics of xylem vessels in rootstock and scion play essential roles in determining the hydraulic properties of the grafted tree; however, much remains unknown for commonly available rootstocks. In this study, we extracted secondary xylem using an increment borer from living Honeycrisp scion (Malus domestica cv. ‘Honeycrisp’), and two Malling rootstocks, one Budagovsky rootstock, and five Geneva rootstocks. The size and density of xylem vessels in rootstocks and scions were analyzed in relation to trunk cross-section area (TCSA), tree–water relations, and fruit dry matter of 2019, as well as with cumulative yield efficiency during 2014–2019. Honeycrisp scion exceeded most of the rootstocks in cross-section size and density of vessel elements. Scion vigor and cumulative yield were positively correlated with TCSA and total vessel cross-section area (VCSA) of the rootstock, with G.202 being the highest, and B.9 being the lowest with small xylem vessels in high density. In the rootstocks with the highest cumulative yield efficiency, the rootstock/scion ratio in VCSA was equal to or slightly higher than 1. Lower scion vessel density in G.214 was associated with lower fruit dry matter weight, more restricted water relations, and worsened leaf chlorosis. G.935 with larger rootstock vessels led to both high yield and high yield efficiency. This suggested that higher scion vessel density and larger rootstock vessel size can be advantageous characteristics for early-stage evaluation. Full article
(This article belongs to the Special Issue Rootstocks: History, Physiology, Management and Breeding)
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Article
Superior Line from Anther Culture of Dendrocalamus latiflorus Selected after Field Trial
Horticulturae 2021, 7(5), 98; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050098 - 03 May 2021
Viewed by 363
Abstract
The selection of superior lines is extremely important to improve the utilization rate and economic value of bamboo. In this research, 120 anther-regenerated bamboo lines were planted in the field, and the survival rate reached 84.2% one year after planting. During five years [...] Read more.
The selection of superior lines is extremely important to improve the utilization rate and economic value of bamboo. In this research, 120 anther-regenerated bamboo lines were planted in the field, and the survival rate reached 84.2% one year after planting. During five years of observations, we continuously measured and recorded the number of shoots and the size of the new bamboo of these regenerated lines. The results showed that there were considerable differences in culm size and growth rate among the different lines. After comprehensive evaluation, we found that one of the lines (P82) had obvious advantages in culm size and growth rate compared with the others. The chromosome ploidy of line P82 and the other three lines (P38, P84, and P34) was detected. It was found that P82 was hexaploid, while the other three lines were dodecaploid. Nutritional components of the P82 shoots were further detected. The results showed that the content of soluble sugar was 1.4%, the content of free amino acid was 3.5 g·kg−1 (FW, fresh weight), and the content of protein was 14.8 g·kg−1 (FW), and there were no significant differences compared with the local wild mature bamboo. Anatomical analysis showed that the vascular bundle size of the line P82 (hexaploid) was significantly larger than that of line P38 (dodecaploid), and the length of parenchyma cells in the culm wall of line P82 was similar to that of line P38, however, the cell width of line P82 was significantly wider than that of line P38. In this study, the breeding of superior lines of regenerated bamboo plants from an anther culture was realized, which provided an example for a new method for selecting superior lines from an anther culture, and also enriched the resources of superior lines of D. latiflorus. Full article
(This article belongs to the Special Issue Application of Tissue Culture to Horticulture)
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Article
Genome-Wide Identification and Expression Analysis of MYB Transcription Factors and Their Responses to Abiotic Stresses in Woodland Strawberry (Fragaria vesca)
Horticulturae 2021, 7(5), 97; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050097 - 02 May 2021
Viewed by 514
Abstract
Woodland strawberry (Fragaria vesca) is a diploid strawberry that is widely used as a model of cultivated octoploid strawberry (Fragaria × ananassa). It has also been used as a model for Rosaceae fruits, non-climacteric fruits, and stolons. The MYB [...] Read more.
Woodland strawberry (Fragaria vesca) is a diploid strawberry that is widely used as a model of cultivated octoploid strawberry (Fragaria × ananassa). It has also been used as a model for Rosaceae fruits, non-climacteric fruits, and stolons. The MYB superfamily is the largest transcription factor family in plants, and its members play important roles in plant growth and development. However, the complete MYB superfamily in woodland strawberry has not been studied. In this study, a total of 217 MYB genes were identified in woodland strawberry and classified into four groups: one 4R-MYB protein, five 3R-MYB proteins, 113 2R-MYB proteins, and 98 1R-MYB proteins. The phylogenetic relationship of each MYB subgroup was consistent in terms of intron/exon structure and conserved motif composition. The MYB genes in woodland strawberry underwent loss and expansion events during evolution. The transcriptome data revealed that most FveMYB genes are expressed in several organs, whereas 15 FveMYB genes exhibit organ-specific expression, including five genes (FveMYB101, -112, -44, and -8; FveMYB1R81) in roots, two genes (FveMYB62 and -77) in stolon tips, three genes (FveMYB99 and -35; FveMYB1R96) in open flowers, and five genes (FveMYB76 and -100; FveMYB1R4, -5, and -86) in immature fruits. During fruit ripening of woodland strawberry, the expression levels of 84 FveMYB genes were decreased, of which five genes (FveMYB4, -22, -50, and -66; FveMYB1R57) decreased more than 10-fold, whereas those 18 FveMYB genes were increased, especially FveMYB10 and FveMYB74 increased more than 30-fold. In addition, the expression levels of 36, 68, 52, and 62 FveMYB genes were altered by gibberellic acid, abscisic acid, cold, and heat treatments, respectively, and among them, several genes exhibited similar expression patterns for multiple treatments, suggesting possible roles in the crosstalk of multiple signaling pathways. This study provides candidate genes for the study of stolon formation, fruit development and ripening, and abiotic stress responses. Full article
(This article belongs to the Section Genetics, Genomics, Breeding, and Biotechnology (G2B2))
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Article
Quality Evaluation of Indoor-Grown Microgreens Cultivated on Three Different Substrates
Horticulturae 2021, 7(5), 96; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050096 - 02 May 2021
Viewed by 724
Abstract
The microgreens are innovative products in the horticultural sector. They are appreciated by consumers thanks to their novelty and health-related benefits, having a high antioxidant concentration. This produce can be adopted for indoor production using hydroponic systems. The aim of the present work [...] Read more.
The microgreens are innovative products in the horticultural sector. They are appreciated by consumers thanks to their novelty and health-related benefits, having a high antioxidant concentration. This produce can be adopted for indoor production using hydroponic systems. The aim of the present work was to investigate the influence of three growing media (vermiculite, coconut fiber, and jute fabric) on yield and quality parameters of two basil varieties (Green basil—Ocimum basilicum L., Red basil—Ocimum basilicum var. Purpurecsens) and rocket (Eruca sativa Mill.) as microgreens. Microgreens were grown in floating, in a Micro Experimental Growing (MEG®) system equipped with LED lamps, with modulation of both energy and spectra of the light supplied to plants. Results showed high yield, comprised from 2 to 3 kg m−2. Nutritional quality varied among species and higher antioxidant compounds were found in red basil on vermiculite and jute. Coconut fiber allowed the differentiation of crop performance in terms of sucrose and above all nitrate. In particular, our results point out that the choice of the substrate significantly affected the yield, the dry matter percentage and the nitrate concentration of microgreens, while the other qualitative parameters were most influenced by the species. Full article
(This article belongs to the Special Issue Urban Horticulture - New Trends and Technologies)
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Article
Effect of 5-Aminolevulinic Acid (5-ALA) on Leaf Chlorophyll Fast Fluorescence Characteristics and Mineral Element Content of Buxus megistophylla Grown along Urban Roadsides
Horticulturae 2021, 7(5), 95; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050095 - 02 May 2021
Viewed by 501
Abstract
It is well known that trees grown on roadsides suffer from stressful environments, including poor soils, bad weather, and harmful gases from automobile exhaust. Improving the adaptability of roadside trees to adverse environments is important for urban management. An experiment was carried out [...] Read more.
It is well known that trees grown on roadsides suffer from stressful environments, including poor soils, bad weather, and harmful gases from automobile exhaust. Improving the adaptability of roadside trees to adverse environments is important for urban management. An experiment was carried out with six-year-old Buxus megistophylla Levl. hedgerows, where 20 mg/L 5-aminolevulinic acids (5-ALA) solution was sprayed on the blade surface at the end of April. Three months later, plant morphology, chlorophyll fast fluorescence characteristics, antioxidant enzyme activities and the mineral element content were investigated. The results showed that leaf size and thickness were significantly greater with 5-ALA treatment, and the leaf color was also greener than those of the control. 5-ALA treatment significantly promoted the electron transfer activity of the PSII reaction center on the donor side, the reaction center itself and the receptor side. It reduced energy dissipation through the heat with increased photochemical quantum yields. The activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in leaves and roots, were stimulated by 5-ALA treatment. The content of soluble sugars and free proline in leaves was significantly increased by 5-ALA treatment, as were the absorption and accumulation of several kinds of mineral nutrient elements, such as nitrogen, phosphate, calcium, magnesium, iron, copper and boron. Additionally, 5-ALA application significantly increased the content of cadmium, mercury, chromium and lead in the roots but decreased them in the leaves. This implies that 5-ALA may induce a mechanism in B. megistophylla in which toxic elements were intercepted in roots to avoid accumulation in leaves, which ensured healthy growth of the aboveground tissues. 5-ALA may regulate the absorption and utilization of mineral nutrient elements in soil with the interception of toxic heavy metal elements in roots, promote leaf photosynthetic performance, induce the accumulation of soluble sugars and free proline, and improve the antioxidant enzyme systems for plants to adapt to the stressful environment of urban roads. These results provide a basis for 5-ALA applications alongside city roads. Full article
(This article belongs to the Special Issue Study of the Influence of Abiotic and Biotic Stress Factors on Plants)
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Article
Multi-Omics Analysis to Visualize Ecotype-Specific Heterogeneity of the Metabolites in the Mesocarp Tissue of Three Avocado (Persea Americana Mill.) Ecotypes
Horticulturae 2021, 7(5), 94; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050094 - 01 May 2021
Viewed by 470
Abstract
The huge amount of metabolites in avocado mesocarp influences the commercial production of specific avocado fruits for consumption and for industrial applications. Additionally, the diversity in the metabolite content may be used as biomarker for differentiating among various avocado ecotypes. However, the differences [...] Read more.
The huge amount of metabolites in avocado mesocarp influences the commercial production of specific avocado fruits for consumption and for industrial applications. Additionally, the diversity in the metabolite content may be used as biomarker for differentiating among various avocado ecotypes. However, the differences in metabolites in avocado remain unclear among various avocado ecotypes. In this study, we first compared the lipid droplets, fatty acid compositions, and gene expression profiles of the mature avocado mesocarps of three ecotypes, and confirmed the differences in the mesocarp oil contents. Furthermore, the lipidomics and metabolomics based on the ultra-high-performance liquid chromatography-triple and time-of-flight mass spectrometry and ultra-high performance liquid chromatography-Q exactive-mass spectrometry were completed, respectively, which revealed considerable differences in the relative amounts of lipids from 10 classes and other metabolites from seven super-classes among the examined avocado ecotypes. The profiles of 65 lipids and 15 other metabolites could be potential candidate biomarkers useful for identifying diverse avocado ecotypes. This is the first comprehensive metabolomics-based comparative investigation of lipid and other metabolites among three avocado ecotypes. Full article
(This article belongs to the Special Issue Physico-Chemical Characterization of Fruits and Vegetables)
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Article
Effects of Shade Net Colors on Mineral Elements and Postharvest Shelf Life and Quality of Fresh Fig (Ficus carica L.) under Rain-Fed Condition
Horticulturae 2021, 7(5), 93; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050093 - 01 May 2021
Cited by 1 | Viewed by 446
Abstract
Photoselective netting is well known for filtering the intercepted solar radiation, thus affecting light quality. While its effects on leaf mineral elements have been well investigated, how color netting affects fruit mineral nutrients remains elusive. This study was conducted to evaluate the effects [...] Read more.
Photoselective netting is well known for filtering the intercepted solar radiation, thus affecting light quality. While its effects on leaf mineral elements have been well investigated, how color netting affects fruit mineral nutrients remains elusive. This study was conducted to evaluate the effects of shade provided by blue and yellow nets on mineral nutrients of fig trees under rain-fed conditions. The experiment was arranged as a split-plot treatment in a randomized complete block design with three replications. Cultivars “Sabz” and “Siah” were covered with color nets or left uncovered (as the control group). The highest nitrogen content (8710 ppm) was recorded for cultivar “Sabz” covered with blue net. Color nets enhanced calcium concentration in cultivar “Siah”. Covering fig trees with yellow net increased magnesium content in cultivar “Siah” and phosphorus content in cultivar “Sabz”. Our observation showed the significant positive effect of photo selective nets on postharvest quality, by decreasing fig fruit weight loss and extending shelf life of fruits. In general, color nets as a new agro-technological approach can maintain fruit nutrition under rain-fed conditions and increase postharvest shelf life and quality of fresh fig. Full article
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Article
Generation of a High-Density Genetic Map of Pepper (Capsicum annuum L.) by SLAF-seq and QTL Analysis of Phytophthora capsici Resistance
Horticulturae 2021, 7(5), 92; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050092 - 01 May 2021
Viewed by 571
Abstract
Pepper (Capsicum annuum L.) is an economically significant global crop and condiment. Its yield can be severely reduced by the oomycete plant pathogen, Phytophthora capsici (P. capsici). Here, a high-density genetic map was created with a mapping panel of F [...] Read more.
Pepper (Capsicum annuum L.) is an economically significant global crop and condiment. Its yield can be severely reduced by the oomycete plant pathogen, Phytophthora capsici (P. capsici). Here, a high-density genetic map was created with a mapping panel of F2 populations obtained from 150 individuals of parental lines PI201234 and 1287 and specific-locus amplified fragment sequencing (SLAF) that was then utilized to identify loci that are related to resistance to P. capsici. The sequencing depth of the genetic map was 108.74-fold for the male parent, 126.25-fold for the female parent, and 22.73-fold for the offspring. A high-resolution genetic map consisting of 5565 markers and 12 linkage groups was generated for pepper, covering 1535.69 cM and an average marker distance of 0.28 cM. One major quantitative trait locus (QTL) for the P. capsici resistance (CQPc5.1) was identified on Chr05 that explained the observed 11.758% phenotypic variance. A total of 23 candidate genes located within the QTL CQPc5.1 interval were identified, which included the candidate gene Capana05g000595 that encodes the RPP8-like protein as well as two candidate genes Capana05g000596 and Capana05g000597 that encodes a RPP13-like protein. Quantitative reverse-transcription PCR (qRT-PCR) revealed higher expression levels of Capana05g000595, Capana05g000596, and Capana05g000597 in P. capsici resistance accessions, suggesting their association with P. capsici resistance in pepper. Full article
(This article belongs to the Special Issue Advances in Molecular Breeding of Vegetable Crops)
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Article
Phytochemical Profile and Antioxidant Properties of Italian Green Tea, a New High Quality Niche Product
Horticulturae 2021, 7(5), 91; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050091 - 27 Apr 2021
Viewed by 409
Abstract
The hot beverage commonly known as tea results from the infusion of dried leaves of the plant Camellia sinensis (L.) O. Kuntze. Ranking second only to water for its consumption worldwide, it has always been appreciated since antiquity for its aroma, taste characteristics, [...] Read more.
The hot beverage commonly known as tea results from the infusion of dried leaves of the plant Camellia sinensis (L.) O. Kuntze. Ranking second only to water for its consumption worldwide, it has always been appreciated since antiquity for its aroma, taste characteristics, and beneficial effects on human health. There are many different processed tea types, including green tea, a non-fermented tea which, due to oxidation prevention maintains the structure of the bioactive compounds, especially polyphenols; these bioactive compounds show a number of benefits for the human health. The main producers of tea are China and India, followed by Kenya, Sri Lanka, Turkey, and Vietnam, however recently new countries are entering the market, with quality niche productions, among which also Italy. The present research aimed to assess the bioactive compounds (polyphenols) and the antioxidant activity of two green teas (the “Camellia d’Oro” tea—TCO, and the “Compagnia del Lago” tea—TCL) produced in Italy, in the Lake Maggiore district, where nurserymen have recently started to cultivate C. sinensis. In this area the cultivation of acidophilic plants as ornamentals has been known since around 1820. Due to the crisis of the floricultural sector, producers have been trying to diversify their product in order to increase their competitiveness, starting to cultivate Italian tea. Their antioxidant activity was assessed, finding a similar or higher antioxidant capacity than in other green teas, as reported in literature. TCO showed a higher antioxidant activity (42,758.86 mmol Fe2+ kg−1; 532.37 µmol TE g−1 DW; 881.08 µmol TE g−1 DW) and phenolic content (14,918.91 mg GAE 100 g−1 DW) than TCL (25,796.61 mmol Fe2+ kg−1; 302.35 µmol TE g−1 DW; 623.44 µmol TE g−1 DW; 8540.42 mg GAE 100 g−1 DW). Through HPLC, a total of thirteen phenolic compounds were identified quantitatively, including catechins, benzoic acids, cinnamic acids, and flavonols, in TCO while only 9 in TCL, and mainly in lower amounts. Albeit with differences, both teas were found to be of quality proving that Italy could have the possibility to grow profitably C. sinensis. Full article
(This article belongs to the Special Issue Nutritional and Antioxidant Value of Horticulturae Products)
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Article
Setting Up a Lab-Scale Pilot Plant to Study the New Growing System (NGS®) for Leafy Vegetable and Culinary Herb Growth
Horticulturae 2021, 7(5), 90; https://0-doi-org.brum.beds.ac.uk/10.3390/horticulturae7050090 - 27 Apr 2021
Viewed by 578
Abstract
New cultural techniques have been developed to improve the yield and raw material quality at harvest, and enhance the postharvest shelf life, by standardizing the growing system. Among the different Soilless Cultivation Systems, the New Growing System (NGS®) is a closed-recirculating [...] Read more.
New cultural techniques have been developed to improve the yield and raw material quality at harvest, and enhance the postharvest shelf life, by standardizing the growing system. Among the different Soilless Cultivation Systems, the New Growing System (NGS®) is a closed-recirculating system that was designed for open fields and protected cultivations. The aim of this work was to investigate the structural setting of the system and its functioning to harness the full potentiality of NGS®. A lab-scale pilot plant (LSPP) was designed with NGS® technology and the technical aspects have been set up to have a standardized and reproducible growing system. The trials were conducted on growing mature-leaf vegetable species; that is, on both head and multi-leaf vegetables, and on culinary herbs at high plant densities. Positive yield results were found for culinary herbs and leafy vegetables. Mints showed high yields for the two re-growths carried out after the first harvest. The LSPP can also be used in a series of reliable experiments and enable researches to test several species, substrates, hydroponic nutrient solutions, and fertigation scheduling. Full article
(This article belongs to the Special Issue Feature Papers in Horticulturae Ⅱ)
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