Horticulturae

18 pages, 4029 KiB

Open AccessEditor’s ChoiceArticle

Rootstock-Mediated Transcriptional Changes Associated with Cold Tolerance in Prunus mume Leaves

by Faisal Hayat, Chengdong Ma, Shahid Iqbal, Xiao Huang, Ouma Kenneth Omondi, Zhaojun Ni, Ting Shi, Rezwan Tariq, Ummara Khan and Zhihong Gao

Horticulturae 2021, 7(12), 572; https://doi.org/10.3390/horticulturae7120572 - 13 Dec 2021

Cited by 10 | Viewed by 3130

Abstract

Japanese apricot (Prunus mume) is remarkably valuable for its high ornamental and economic importance due to its distinctive features. Low temperature is a serious environmental constraint for this species, restricting its cultivation and dispersal in the north of China. To address [...] Read more.

Japanese apricot (Prunus mume) is remarkably valuable for its high ornamental and economic importance due to its distinctive features. Low temperature is a serious environmental constraint for this species, restricting its cultivation and dispersal in the north of China. To address this issue, breeding requires an understanding of the molecular mechanisms underlying responses to cold stress. We examined the leaf physiological and transcriptome profile by RNA sequencing in ‘Bungo’ scion cultivar grafted onto Prunus mume (cold-sensitive) and Prunus armeniaca (cold-tolerant) rootstocks at 4 °C for 0, 6, and 24 h. Our results revealed that the increased MDA concentration in the leaves of P. mume cultivar (cold-sensitive) suggests that cold stress might cause oxidative damage and increased sensitivity. Moreover, the cold-tolerant cultivar (P. armeniaca) considerably enhances the enzyme activities (i.e., SOD, POD, and CAT), as well as osmo-protectants (soluble sugars and proline) compared with sensitive cultivar, which helps plants to withstand oxidative damage caused by cold stress. Additionally, differentially expressed genes were shown to be enriched in plant hormone signal transduction, ribosome, MAPK signaling, and circadian rhythm pathway. After 24 h of cold stress, genes related to PYL4, histidine kinase 1, SAUR36, bHLH130, bHLH123, TIFY 6B-like, WRKY 40, WRKY 57, and 60S acidic ribosomal protein P1 were differentially expressed, implying that these DEGs involved in multiple pathways are involved in cold tolerance in Japanese apricot. This study improved our current understanding of the mechanism of cold tolerance in Japanese apricot, and the findings could be utilized for other related fruit species. Full article

(This article belongs to the Collection Epigenetic Modifications and Breeding Application in Horticultural Plants)

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13 pages, 1305 KiB

Open AccessEditor’s ChoiceArticle

A Pivotal Role of Chitosan Nanoparticles in Enhancing the Essential Oil Productivity and Antioxidant Capacity in Matricaria chamomilla L.

by Ragia Mazrou, Esmat F. Ali, Sabry Hassan and Fahmy A. S. Hassan

Horticulturae 2021, 7(12), 574; https://doi.org/10.3390/horticulturae7120574 - 13 Dec 2021

Cited by 6 | Viewed by 2277

Abstract

Chitosan is a biopolymer with several biological and agricultural applications. Recently, development of chitosan nanoparticles (CSNPs) adds additional value by further using it as an eco-friendly biostimulant. Therefore, the impact of CSNPs foliar application on the growth, essential oil productivity and antioxidant capacity [...] Read more.

Chitosan is a biopolymer with several biological and agricultural applications. Recently, development of chitosan nanoparticles (CSNPs) adds additional value by further using it as an eco-friendly biostimulant. Therefore, the impact of CSNPs foliar application on the growth, essential oil productivity and antioxidant capacity of chamomile was investigated. Treatments comprised 0, 100, 200, 300 and 400 mg L⁻¹ of CSNPs applied to plants as a foliar spray. CSNPs foliar application improved the growth and productivity of chamomile plants. Relative to the control, the flower yield was increased by 52.10 and 55.74% while the essential oil percentage was increased by 57.14 and 47.06% due to CSNPs at 300 mg L⁻¹ during the two seasons of study. Moreover, CSNPs enhanced the photosynthetic pigments, total soluble sugars and N, P and K percentages. Interestingly, CSNPs increased the antioxidant capacity as measured by total phenolics and the antioxidant activity (DPPH). Collectively, it is suggested that CSNPs might be a promising eco-friendly bio-stimulant and it could be an alternative strategy to improve the productivity, quality and decrease the production cost of chamomile and possibly some other medicinal species. Full article

(This article belongs to the Section Medicinals, Herbs, and Specialty Crops)

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16 pages, 4397 KiB

Open AccessEditor’s ChoiceArticle

Foliar Application of Potassium Mitigates Salinity Stress Conditions in Spinach (Spinacia oleracea L.) through Reducing NaCl Toxicity and Enhancing the Activity of Antioxidant Enzymes

by Tayyaba Naz, Muhammad Mazhar Iqbal, Muhammad Tahir, Montaser M. Hassan, Muhammad Ishaq Asif Rehmani, Mazhar Iqbal Zafar, Umber Ghafoor, Muhammad Akram Qazi, Ayman EL Sabagh and Mohamed I. Sakran

Horticulturae 2021, 7(12), 566; https://doi.org/10.3390/horticulturae7120566 - 9 Dec 2021

Cited by 17 | Viewed by 4630

Abstract

Agronomic biofortification is the purposeful utilization of mineral fertilizers to increase the concentration of desired minerals in edible plant parts for enhancing their dietary intake. It is becoming crucial to enhance the dietary intake of K for addressing hidden hunger and related health [...] Read more.

Agronomic biofortification is the purposeful utilization of mineral fertilizers to increase the concentration of desired minerals in edible plant parts for enhancing their dietary intake. It is becoming crucial to enhance the dietary intake of K for addressing hidden hunger and related health issues such as cardiac diseases and hypertension. This study was designed to enhance the potassium concentration in edible parts of spinach through its foliar application under saline environment. The salinity levels of electrical conductivity (EC) = 4, 6, and 8 dS m⁻¹ were applied using sodium chloride (NaCl) along with control. The levels of K for foliar sprays were 5 and 10 mM, along with control. The present experiment was performed under two factorial arrangements in a completely randomized design (CRD). After 60 days of sowing, the crop was harvested. Data regarding growth, ionic, physiological, and biochemical parameters, i.e., shoot dry weight, relative water content, electrolyte leakage, total chlorophyll content, tissue sodium (Na) and K concentration, activities of superoxide dismutase (SOD), and catalase (CAT) were recorded and those were found to be significantly (p ≤ 0.05) affected by foliar application of K on spinach under saline conditions. The highest growth, physiological and biochemical responses of spinach were observed in response to foliar-applied K at 10 mM. It is concluded that agronomic bio-fortification by foliar use of K can be a useful strategy to increase tissue K intakes and minimize Na toxicity in the vegetables studied under saline conditions. Full article

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

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18 pages, 2791 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

UV-B Radiation as Abiotic Elicitor to Enhance Phytochemicals and Development of Red Cabbage Sprouts

by Lorena Martínez-Zamora, Noelia Castillejo and Francisco Artés-Hernández

Horticulturae 2021, 7(12), 567; https://doi.org/10.3390/horticulturae7120567 - 9 Dec 2021

Cited by 11 | Viewed by 2881

Abstract

Background: The main objective of this study was to evaluate the effect of periodical UV-B illumination during red cabbage germination on morphological development and the phenolics and carotenoid accumulation. Methods: During a sprouting period of 10 days at 20 °C in darkness, seedlings [...] Read more.

Background: The main objective of this study was to evaluate the effect of periodical UV-B illumination during red cabbage germination on morphological development and the phenolics and carotenoid accumulation. Methods: During a sprouting period of 10 days at 20 °C in darkness, seedlings received 5, 10, or 15 kJ m⁻² UV-B (T5, T10, and T15) applied in four steps (25% on days 3, 5, 7, and 10). UV untreated sprouts were used as control (CTRL). After 10 days of germination, the sprouts were harvested and stored 10 days at 4 °C as a minimally processed product. Phenolic and carotenoid compounds were analysed 1 h after each UV-B application and on days 0, 4, 7, and 10 during cold storage. Results: The longest hypocotyl length was observed in T10-treated sprouts. The total phenolic content (TPC), total flavonoid content (TFC), and total antioxidant capacity (TAC) increased during germination following a sigmoidal kinetic, especially in the UV-B-treated samples, which reported a dose-dependent behaviour. In this way, T10-treated sprouts increased the TPC by 40% after 10 days at 4 °C compared to CTRL, while TAC and TFC increased by 35 and 30%, respectively. Carotenoids were enhanced with higher UV-B doses (T15). Conclusions: We found that UV-B stimulated the biosynthesis of bioactive compounds, and a dose of 10 kJ m⁻² UV-B, proportionally applied on days 3, 5, 7, and 10 days, is recommended. Full article

(This article belongs to the Special Issue Quality and Safety of Fresh Fruits and Vegetables)

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13 pages, 2416 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Efficiency of Reductive Soil Disinfestation Affected by Soil Water Content and Organic Amendment Rate

by Rui Zhu, Xinqi Huang, Jinbo Zhang, Zucong Cai, Xun Li and Teng Wen

Horticulturae 2021, 7(12), 559; https://doi.org/10.3390/horticulturae7120559 - 7 Dec 2021

Cited by 5 | Viewed by 2390

Abstract

Reductive Soil Disinfestation (RSD) is a good method which can restore degraded greenhouse soil and effectively inactivate soil-borne pathogens. However, the approach needs to be optimized in order to facilitate its practical application in various regions. In the present work, we investigated the [...] Read more.

Reductive Soil Disinfestation (RSD) is a good method which can restore degraded greenhouse soil and effectively inactivate soil-borne pathogens. However, the approach needs to be optimized in order to facilitate its practical application in various regions. In the present work, we investigated the effect of soil water content (60% water holding capacity (WHC), 100% WHC and continuous flooding) and maize straw application rates (0, 5, 10, and 20 g kg⁻¹ soil) on the improvement of soil properties and suppression of soil-borne pathogens (Fusarium oxysporum, Pythium and Phytophthora). The results showed that increasing the soil water content and maize straw application rate accelerated the removal of excess sulfate and nitrate in the soil and elevated the soil pH. Elevating the water content and maize straw application rate also produced much more organic acids, which could strongly inhibit soil-borne pathogens. Soil properties were improved significantly after RSD treatment with a maize straw amendment rate of more than 5 g kg⁻¹, regardless of the water content. However, RSD treatments with 60% WHC could not effectively inactivate soil-borne pathogens and even stimulated their growth by increasing the maize application rate. RSD treatments of both 100% WHC and continuous flooding could inactivate soil-borne pathogens and increase the pathogens mortality indicated by cultural cells relatively effectively. The inhibited pathogens were significantly increased with the increasing maize application rate from 5 g kg⁻¹ to 10 g kg⁻¹, but were not further increased from 10 g kg⁻¹ to 20 g kg⁻¹. A further increased mortality of F. oxysporum, indicated by gene copies, was also observed when the soil water content and maize straw application rate were increased. Therefore, RSD treatment with 60% WHC could improve soil properties significantly, whereas irrigation with 100% WHC or continuous flooding was a necessity for effective soil-borne pathogens suppression. Holding 100% WHC and applicating maize straw at 10 g kg⁻¹ soil were optimum conditions for RSD field operation to restore degraded greenhouse soil. Full article

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

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21 pages, 43808 KiB

Open AccessEditor’s ChoiceArticle

Effect of Three Water Regimes on the Physiological and Anatomical Structure of Stem and Leaves of Different Citrus Rootstocks with Distinct Degrees of Tolerance to Drought Stress

by Waqar Shafqat, Yasser S. A. Mazrou, Sami-ur-Rehman, Yasser Nehela, Sufian Ikram, Sana Bibi, Summar A. Naqvi, Mansoor Hameed and Muhammad Jafar Jaskani

Horticulturae 2021, 7(12), 554; https://doi.org/10.3390/horticulturae7120554 - 6 Dec 2021

Cited by 15 | Viewed by 4461

Abstract

Citrus is grown globally throughout the subtropics and semi-arid to humid tropics. Abiotic stresses such as soil water deficit negatively affect plant growth, physiology, biochemistry, and anatomy. Herein, we investigated the effect(s) of three water regimes (control, moderate drought, and severe drought) on [...] Read more.

Citrus is grown globally throughout the subtropics and semi-arid to humid tropics. Abiotic stresses such as soil water deficit negatively affect plant growth, physiology, biochemistry, and anatomy. Herein, we investigated the effect(s) of three water regimes (control, moderate drought, and severe drought) on the physiological and anatomical structure of 10 different citrus rootstocks with different degrees of tolerance to drought stress. Brazilian sour orange and Gadha dahi performed well by avoiding desiccation and maintaining plant growth, plant water status, and biochemical characters, while Rangpur Poona nucellar (C. limonia) and Sunki × bentake were the most sensitive rootstocks at all stress conditions. At severe water stress, the highest root length (24.33 ± 0.58), shoot length (17.00 ± 1.00), root moisture content (57.67 ± 1.53), shoot moisture content (64.59 ± 1.71), and plant water potential (−1.57 ± 0.03) was observed in tolerant genotype, Brazilian sour orange. Likewise, chlorophyll a (2.70 ± 0.06), chlorophyll b (0.87 ± 0.06) and carotenoids (0.69 ± 0.08) were higher in the same genotype. The lowest H₂O₂ content (77.00 ± 1.00) and highest proline content (0.51 ± 0.06) were also recorded by Brazilian sour orange. The tolerance mechanism of tolerant genotypes was elucidated by modification in anatomical structures. Stem anatomy at severe drought, 27.5% increase in epidermal cell thickness, 25.4% in vascular bundle length, 30.5% in xylem thickness, 27.7% in the phloem cell area, 8% in the pith cell area, and 43.4% in cortical thickness were also observed in tolerant genotypes. Likewise, leaf anatomy showed an increase of 27.9% in epidermal cell thickness, 11.4% in vascular bundle length, 21% in xylem thickness, and 15% in phloem cell area in tolerant genotypes compared with sensitive ones. These modifications in tolerant genotypes enabled them to maintain steady nutrient transport while reducing the risk of embolisms, increasing water-flow resistance, and constant transport of nutrients across. Full article

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

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15 pages, 3586 KiB

Open AccessEditor’s ChoiceArticle

Seaweed Extract Improves Lagenaria siceraria Young Shoot Production, Mineral Profile and Functional Quality

by Beppe Benedetto Consentino, Leo Sabatino, Rosario Paolo Mauro, Carlo Nicoletto, Claudio De Pasquale, Giovanni Iapichino and Salvatore La Bella

Horticulturae 2021, 7(12), 549; https://doi.org/10.3390/horticulturae7120549 - 3 Dec 2021

Cited by 11 | Viewed by 2640

Abstract

Vegetable landraces represent the main source of biodiversity in Sicily. Lagenaria siceraria is appreciated by Southern Mediterranean consumers for its immature fruits and young shoots. Plant-based biostimulants supply, such as seaweed extract (SwE), is a contemporary and green agricultural practice applied to ameliorate [...] Read more.

Vegetable landraces represent the main source of biodiversity in Sicily. Lagenaria siceraria is appreciated by Southern Mediterranean consumers for its immature fruits and young shoots. Plant-based biostimulants supply, such as seaweed extract (SwE), is a contemporary and green agricultural practice applied to ameliorate the yield and quality of vegetables. However, there are no studies concerning the effects of SwE on L. siceraria. The current study evaluated the effects of SwE foliar application (0 or 3 mL L⁻¹) on five L. siceraria landraces (G1, G2, G3, G4 and G5) grown in greenhouses. Growth traits, first female flower emission, fruit yield, young shoot yield, fruit firmness, young shoot nitrogen use efficiency (NUE_ys) and specific young shoot quality parameters, such as soluble solids content (SSC), mineral profile, ascorbic acid, and polyphenols, were appraised. Plant height and number of leaves at 10, 20 and 30 days after transplant (DAT) were significantly higher in plants treated with SwE as compared with untreated plants. Treating plants with SwE increased marketable fruit yield, fruit mean mass, young shoot yield and number of young shoots by 14.4%, 15.0%, 22.2%, 32.4%, and 32.0%, respectively as compared with untreated plants. Relevant increments were also recorded for NUE_ys, P, K, Ca, Mg, ascorbic acid and polyphenols concentration. SwE application did not significantly affect total yield and SSC. Furthermore, SwE treated plants produced a lower number of marketable fruits than non-treated plants. The present study showed that SwE at 3 mL L⁻¹ can fruitfully enhance crop performance, young shoot yield and quality of L. siceraria. Full article

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

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7 pages, 207 KiB

Open AccessEditor’s ChoiceReview

The Pour-Through Procedure for Monitoring Container Substrate Chemical Properties: A Review

by James E. Altland

Horticulturae 2021, 7(12), 536; https://doi.org/10.3390/horticulturae7120536 - 2 Dec 2021

Cited by 10 | Viewed by 1711

Abstract

The pour-through procedure is a nondestructive method commonly used by horticultural crop producers and research scientists to measure chemical properties and nutrient availability in container substrates. It is a method that uses water as a displacement solution to push the substrate solution out [...] Read more.

The pour-through procedure is a nondestructive method commonly used by horticultural crop producers and research scientists to measure chemical properties and nutrient availability in container substrates. It is a method that uses water as a displacement solution to push the substrate solution out of the bottom of the container so it can be analyzed for pH, electrical conductivity, and nutrient concentrations. The method was first introduced in the early 1980s. Since then, research has been conducted to determine factors that affect the results of the pour-through including volume, nature and timing of application of the displacement solution, container size, and substrate stratification. It has also been validated against other common methods for determining container substrate pH, EC, and nutrient concentration, most notably the saturated media extraction procedure. Over the past 40 years, the method has been proven to be simple, robust, and consistent in providing crop producers and researchers valuable information on substrate chemical properties from which management decisions and experimental inferences can be made. Full article

(This article belongs to the Special Issue Feature Reviews in Floriculture, Nursery and Landscape, and Turf)

16 pages, 8560 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Gene Expression Analysis in Cold Stress Conditions Reveals BBX20 and CLO as Potential Biomarkers for Cold Tolerance in Almond

by Beatriz Bielsa, Jorge Israel Ávila-Alonso, Ángel Fernández i Martí, Jérôme Grimplet and María José Rubio-Cabetas

Horticulturae 2021, 7(12), 527; https://doi.org/10.3390/horticulturae7120527 - 29 Nov 2021

Cited by 4 | Viewed by 2230

Abstract

Late spring frosts can become one of the limiting factors for the expansion of cultivation area towards a harsher climate for the almond [Prunus amygdalus Batsch syn P. dulcis (Mill.) D.A. Webb] crop as spring frost can damage up to 90% of [...] Read more.

Late spring frosts can become one of the limiting factors for the expansion of cultivation area towards a harsher climate for the almond [Prunus amygdalus Batsch syn P. dulcis (Mill.) D.A. Webb] crop as spring frost can damage up to 90% of the harvest. In order to identify key genes favoring cold tolerance in almonds, branches from three late-blooming genotypes: ‘Guara’, ‘Soleta’ and ‘Belona’ were exposed at −4 °C during 24 h in a constant climate chamber. Phenotype analysis showed that ‘Guara’ and ‘Soleta’ had a greater acclimation capacity to cold than ‘Belona’. The qRT-PCR BioMark System technology was used to monitor the relative expression of 30 candidate genes with a potential relation to cold response, which are either involved in the ICE-CBF-COR pathway or the independent CBF pathway, and also genes not yet characterized or with unknown function in almond genome. Differences in the gene expression profiles were found among the three studied genotypes and the three time-points of cold exposure (0, 2 and 24 h). BBX20 and CLO genes behaved as differentiator genes between tolerant and susceptible genotypes in cold stress response in almond pistils. In addition, the differences of expression among the tolerant genotypes suggested the intervention of different mechanisms responding to cold stress in almonds. Full article

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

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14 pages, 492 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Multiple Effects of Nitrogen Fertilization on Grape Vegetative Growth, Berry Quality and Pest Development in Mediterranean Vineyards

by Arturo Cocco, Luca Mercenaro, Enrico Muscas, Alessandra Mura, Giovanni Nieddu and Andrea Lentini

Horticulturae 2021, 7(12), 530; https://doi.org/10.3390/horticulturae7120530 - 29 Nov 2021

Cited by 8 | Viewed by 2511

Abstract

Nitrogen is a key macronutrient for the quantitative and qualitative yield of grapes; in addition, it influences the development and reproduction of grape pests. The multiple effects of different nitrogen rates were investigated on the red berry cultivar ‘Carignano’ and the grape pest [...] Read more.

Nitrogen is a key macronutrient for the quantitative and qualitative yield of grapes; in addition, it influences the development and reproduction of grape pests. The multiple effects of different nitrogen rates were investigated on the red berry cultivar ‘Carignano’ and the grape pest Planococcus ficus in a two-year field trial. Different amounts of ammonium nitrate were compared: 0, 80 and 160 Units ha⁻¹ for mineral nitrogen. The amount of nitrogen fertilization supplied influenced the nitrogen status of vines and increased the pruning weight and leaf area, as well as the overall grape yield, by increasing the cluster weight. However, doubling the nitrogen rate did not generally increase the vegetative and productive parameters of grapevines. At harvest, nitrogen supply did not influence the anthocyanin content, tritatable acidity, and soluble solids, although the latter parameter showed a clear, yet not significant, decreasing trend. Planococcus ficus exhibited higher fecundity, survival and shorter development time on grapevines provided with nitrogen, whereas its fertility was unaffected by nitrogen fertilization. Ultimately, nitrogen had a direct and positive effect on grape yield and vine mealybug development, highlighting the importance of integrated cultural and pest control practices to promote grape production. Full article

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16 pages, 5094 KiB

Open AccessEditor’s ChoiceArticle

Identification of Long Non-Coding RNAs Associated with Tomato Fruit Expansion and Ripening by Strand-Specific Paired-End RNA Sequencing

by Jinyu Wang, Yan Feng, Xiaotao Ding, Jingtian Huo and Wen-Feng Nie

Horticulturae 2021, 7(12), 522; https://doi.org/10.3390/horticulturae7120522 - 25 Nov 2021

Cited by 5 | Viewed by 1941

Abstract

As emerging essential regulators in plant development, long non-coding RNAs (lncRNAs) have been extensively investigated in multiple horticultural crops, as well as in different tissues of plants. Tomato fruits are an indispensable part of people’s diet and are consumed as fruits and vegetables. [...] Read more.

As emerging essential regulators in plant development, long non-coding RNAs (lncRNAs) have been extensively investigated in multiple horticultural crops, as well as in different tissues of plants. Tomato fruits are an indispensable part of people’s diet and are consumed as fruits and vegetables. Meanwhile, tomato is widely used as a model to study the ripening mechanism in fleshy fruit. Although increasing evidence shows that lncRNAs are involved in lots of biological processes in tomato plants, the comprehensive identification of lncRNAs in tomato fruit during its expansion and ripening and their functions are partially known. Here, we performed strand-specific paired-end RNA sequencing (ssRNA-seq) of tomato Heinz1706 fruits at five different developmental stages, as well as flowers and leaves. We identified 17,674 putative lncRNAs by referencing the recently released SL4.0 and annotation ITAG4.0 in tomato plants. Many lncRNAs show different expression patterns in fleshy fruit at different developmental stages compared with leaves or flowers. Our results indicate that lncRNAs play an important role in the regulation of tomato fruit expansion and ripening, providing informative lncRNA candidates for further studies in tomato fruits. In addition, we also summarize the recent advanced progress in lncRNAs mediated regulation on horticultural fruits. Hence, our study updates the understanding of lncRNAs in horticultural plants and provides resources for future studies relating to the expansion and ripening of tomato fruits. Full article

(This article belongs to the Collection Epigenetic Modifications and Breeding Application in Horticultural Plants)

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19 pages, 3890 KiB

Open AccessEditor’s ChoiceArticle

Impact of Chitosan, Sucrose, Glucose, and Fructose on the Postharvest Decay, Quality, Enzyme Activity, and Defense-Related Gene Expression of Strawberries

by Yuanhua Wang, Zhiming Yan, Weihua Tang, Qing Zhang, Bei Lu, Qiong Li and Geng Zhang

Horticulturae 2021, 7(12), 518; https://doi.org/10.3390/horticulturae7120518 - 24 Nov 2021

Cited by 10 | Viewed by 3859

Abstract

Strawberry is one of the most highly consumed fruits worldwide, but is extremely perishable. This study systematically compared the effects of chitosan, sucrose, glucose, and fructose immersion on the physiology and disease development in harvested strawberries. After storage at 15 °C for 9 [...] Read more.

Strawberry is one of the most highly consumed fruits worldwide, but is extremely perishable. This study systematically compared the effects of chitosan, sucrose, glucose, and fructose immersion on the physiology and disease development in harvested strawberries. After storage at 15 °C for 9 days, all sugar treatment groups had significantly higher total soluble solids and total anthocyanin content than those of the control group. All sugar treatment groups inhibited malondialdehyde accumulation. At the end of the storage, chitosan, glucose, and fructose maintained higher superoxide dismutase activity and chitosan maintained higher catalase activity. The chitosan and glucose groups had lowest fruit decay index, followed by sucrose and fructose groups. The fruit firmness and luster were better maintained in the glucose group. Furthermore, genes related to sucrose metabolism (e.g., FaSUS1 and FaSUS2), titratable acidity accumulation (e.g., FaMDH1, FaMDH2, FaCS1, and FaCS2), disease resistance (e.g., FaPGIP1, FaWRKY1, and FaWRKY33) and to anabolic jasmonic acid and abscisic acid pathways (e.g., FaJAZ1, FaJAZ2, FaOPR3, FaNCED1, and FaNCED2) were regulated to varying degrees, suggesting that chitosan and glucose participate in plants’ immune signaling networks and regulate disease resistance in fruit through hormone pathways. The findings provide new insights into the physiological regulation of harvested strawberries. Full article

(This article belongs to the Section Postharvest Biology, Quality, Safety, and Technology)

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19 pages, 2888 KiB

Open AccessEditor’s ChoiceArticle

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

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

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

Cited by 6 | Viewed by 2782

Abstract

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

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

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

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11 pages, 6182 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

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

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

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

Cited by 5 | Viewed by 2175

Abstract

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

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

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

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11 pages, 2953 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

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

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

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

Viewed by 1740

Abstract

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

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

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

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16 pages, 4135 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

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

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

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

Cited by 5 | Viewed by 2450

Abstract

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

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

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

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19 pages, 6427 KiB

Open AccessEditor’s ChoiceArticle

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

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

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

Cited by 8 | Viewed by 2421

Abstract

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

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

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

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11 pages, 5258 KiB

Open AccessEditor’s ChoiceArticle

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

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

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

Cited by 3 | Viewed by 3539

Abstract

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

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

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

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11 pages, 4896 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

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

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

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

Cited by 8 | Viewed by 2261

Abstract

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

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

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

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12 pages, 2426 KiB

Open AccessEditor’s ChoiceArticle

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

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

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

Cited by 11 | Viewed by 5341

Abstract

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

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

(This article belongs to the Section Viticulture)

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17 pages, 13231 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Seed Micromorphology, In Vitro Germination, and Early-Stage Seedling Morphological Traits of Cattleya purpurata (Lindl. & Paxton) Van den Berg

by Miriam Bazzicalupo, Jacopo Calevo, Martino Adamo, Annalisa Giovannini, Andrea Copetta and Laura Cornara

Horticulturae 2021, 7(11), 480; https://doi.org/10.3390/horticulturae7110480 - 10 Nov 2021

Cited by 5 | Viewed by 2763

Abstract

In the context of a symbiotic plant-fungus interaction study concerning Cattleya purpurata, we focused on some aspects of seed morphology and biology, and the early stages of seedling development. Seed morphology was characterized using light and scanning electron microscopy. In vitro seed [...] Read more.

In the context of a symbiotic plant-fungus interaction study concerning Cattleya purpurata, we focused on some aspects of seed morphology and biology, and the early stages of seedling development. Seed morphology was characterized using light and scanning electron microscopy. In vitro seed germination capability was evaluated, comparing symbiotic and asymbiotic methods. The morphology of the seeds was overall comparable to that of other congeneric species, showing classical adaptations related to the aerodynamic properties and to the wettability of seeds, but calcium oxalate druses were identified inside the suspensor cells. Asymbiotic seed germination was successful in all tested media (17.1–46.5%) but was higher on 1/2 Murashige & Skoog. During symbiotic interaction with the fungal strain MUT4178 (Tulasnella calospora), germination rate was significantly lower than that obtained with the best three asymbiotic media, suggesting a low fungal compatibility. Seedling morphology was in line with other taxa from the same genus, showing typical characteristics of epiphytic species. Our observations, in particular, highlighted the presence of stomata with C-shaped guard cells in the leaves, rarely found in Cattleyas (where usually they are reniform), and confirm the presence of tilosomes in the roots. Idioblasts containing raphides were observed in both roots and leaves. Full article

(This article belongs to the Special Issue Feature Papers in Horticulturae Ⅱ)

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24 pages, 8066 KiB

Open AccessEditor’s ChoiceArticle

Effects of Temperature and Photoperiod on the Flower Potential in Everbearing Strawberry as Evaluated by Meristem Dissection

by Samia Samad, Denis Butare, Salla Marttila, Anita Sønsteby and Sammar Khalil

Horticulturae 2021, 7(11), 484; https://doi.org/10.3390/horticulturae7110484 - 10 Nov 2021

Cited by 7 | Viewed by 3275

Abstract

The growing interest in using everbearing (EB) strawberry cultivars to extend the cultivation period has faced some challenges. These include poor runner production due to its perpetual flowering nature; irregular flowering behavior and extended periods of high temperature have caused floral inhibition and [...] Read more.

The growing interest in using everbearing (EB) strawberry cultivars to extend the cultivation period has faced some challenges. These include poor runner production due to its perpetual flowering nature; irregular flowering behavior and extended periods of high temperature have caused floral inhibition and reduced yield. As flowering is an interplay between temperature and photoperiod, it is important to investigate the effects of this interaction on the cultivation. Therefore, this study used meristem dissection as a tool to study the effect of temperature and photoperiod on meristem development. Tray plants of two EB strawberry cultivars ‘Florentina’ and ‘Favori’ were grown at 20 °C, 25 °C, and 30 °C under short day (SD) conditions, and subsequently at 20 °C under long day (LD) conditions. The meristem development was analysed every 6 weeks for a 15-week period in SD and for 14 weeks in LD conditions using meristem dissection. The plants showed similar flowering patterns to previously studied everbearing cultivars, which was qualitative LD plants at high temperatures and quantitative LD plants at lower temperatures. Our results show that meristem dissection can be used to determine the temperature and photoperiodic effect on meristem development, and for the occurrence of cropping peaks, and can therefore be used to decide the environmental input and to evaluate yield potential. Full article

(This article belongs to the Collection New Challenges in Productivity of Berry Fruits)

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18 pages, 3089 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Application of Rosemary and Eucalyptus Essential Oils and Their Main Component on the Preservation of Apple and Pear Fruits

by Panayiota Xylia, Antonios Chrysargyris, Zienab F. R. Ahmed and Nikolaos Tzortzakis

Horticulturae 2021, 7(11), 479; https://doi.org/10.3390/horticulturae7110479 - 9 Nov 2021

Cited by 31 | Viewed by 3464

Abstract

Nowadays, increase fruit losses are being reported due to the development of fungal postharvest diseases. In an attempt to reduce the use of synthetic fungicides, a turn towards natural products such as essential oils (EOs) and natural compounds has been made. The objective [...] Read more.

Nowadays, increase fruit losses are being reported due to the development of fungal postharvest diseases. In an attempt to reduce the use of synthetic fungicides, a turn towards natural products such as essential oils (EOs) and natural compounds has been made. The objective of this study was to investigate the effects of eucalyptus (Euc), rosemary (Ros) EO, their mixture (50:50 v/v) and their common main component (i.e., eucalyptol) on the quality parameters, fruit response and inhibition of blue rot (Penicillium expansum) in apple and pear fruits during their shelf life. The results of the present study revealed that fungal colony growth decreased in vitro with exposure at eucalyptus EO (Euc-300 μL/L), rosemary EO (Ros-300 μL/L) and their mixture (Euc + Ros 100 and 300 μL/L). The exposure at Ros-100 μL/L stimulated spore production, whilst Euc + Ros (100 and 300 μL/L) and eucalyptol (100 and 300 μL/L) decreased spore germination. Moreover, the in vivo applied treatments resulted in decreased lesion growth of P. expansum in apple and pear fruits. Respiration rate increased with the application of Euc + Ros at 300 μL/L and eucalyptus EO (Euc-100 μL/L and Euc-300 μL/L) for both assessed fruits. On the other hand, no significant differences were reported on apples and pears total soluble solids and acidity values. The application of Euc + Ros-300 μL/L in apples increased hydrogen peroxide (H₂O₂) levels, whilst Euc-100 and Euc-300 μL/L increased lipid peroxidation levels. Regarding pear fruits, exposure to Euc-100 μL/L and Ros-100 μL/L resulted in increased H₂O₂ whereas, Euc-100 μL/L, Ros- (100 and 300 μL/L) and eucalyptol (100 and 300 μL/L) also increased lipid peroxidation. The findings of this study indicate that the investigated natural products can be explored for the preservation of fresh apples and pears, as alternative natural fungicides with consideration of the fresh produce quality attributes. Full article

(This article belongs to the Special Issue Biological Control of Pre- and Postharvest Fungal Diseases)

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11 pages, 614 KiB

Open AccessEditor’s ChoiceArticle

Screening of Amaranthus sp. Varieties for Resistance to Bacterial Wilt Caused by Ralstonia solanacearum

by Rachidatou Sikirou, Marie Epiphane Dossoumou, Judith Honfoga, Victor Afari-Sefa, Ramasamy Srinivasan, Mathews Paret and Wubetu Bihon

Horticulturae 2021, 7(11), 465; https://doi.org/10.3390/horticulturae7110465 - 4 Nov 2021

Cited by 2 | Viewed by 2187

Abstract

Bacterial wilt, caused by Ralstonia solanacearum, is an emerging constraint in amaranth production in Benin. Host resistance is the most sustainable disease control measure. Ten amaranth varieties including A2002, Bresil (B) -Sel, Madiira 2, AC-NL, GARE ES13-7, Madiira 1, UG-AMES13-2, AM-NKGN, IP-5-Sel [...] Read more.

Bacterial wilt, caused by Ralstonia solanacearum, is an emerging constraint in amaranth production in Benin. Host resistance is the most sustainable disease control measure. Ten amaranth varieties including A2002, Bresil (B) -Sel, Madiira 2, AC-NL, GARE ES13-7, Madiira 1, UG-AMES13-2, AM-NKGN, IP-5-Sel and a local variety from Benin were screened for resistance to bacterial wilt. The study was conducted in a screen house and in the naturally contaminated open field during a consecutive rainy and dry season using a randomized complete block design with four and three replications, respectively. In the screen house, plants were inoculated by drenching a 40 mL of bacterial suspension containing 10⁸ CFU/mL of R. solanacearum strain NCBI 5 GenBank N° MH397250 at the collar region. The bacterial wilt incidence (BWI) and the area under the disease progress curve (AUDPC) suggested differential reactions of amaranth varieties to the pathogen. BWI and AUDPC were low for UG-AMES13-2, moderate for Madiira 2, AM-NKGN and the local variety and very high for A2002, Bresil (B) -Sel, AC-NL, GARE ES13-7, Madiira 1 and IP-5-Sel. The World Vegetable Center’s UG-AMES13-2 can be considered as first choice, which is resistant to R. solanacearum, and should be scaled up for seed production towards supporting farmers. Full article

(This article belongs to the Section Plant Pathology and Disease Management (PPDM))

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16 pages, 1830 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Molecular Insights into the Effects of Rootstocks on Maturation of Blood Oranges

by Giuseppe Lana, Giulia Modica, Giuseppina Las Casas, Laura Siracusa, Stefano La Malfa, Alessandra Gentile, Angelo Sicilia, Gaetano Distefano and Alberto Continella

Horticulturae 2021, 7(11), 468; https://doi.org/10.3390/horticulturae7110468 - 4 Nov 2021

Cited by 15 | Viewed by 2330

Abstract

Rootstock choice has important effects on the horticultural and pathological traits of the citrus cultivars. Thus, the scion/rootstock combination can affect tree vigour, nutrition, and stress resistance; it can also have positive influences on the fruit quality traits. Although the study of rootstock [...] Read more.

Rootstock choice has important effects on the horticultural and pathological traits of the citrus cultivars. Thus, the scion/rootstock combination can affect tree vigour, nutrition, and stress resistance; it can also have positive influences on the fruit quality traits. Although the study of rootstock effects has been a relevant research topic in citrus for many years, the main body of such study has been conducted at the biochemical level, while little effort has been directed to the determination of the rootstock influences at the molecular level. A comparative study of three combinations of scion and rootstock shows a positive correlation between the regulation of the fruit quality-related genes and the accumulations of bioactive compounds, as well as with acid degradation. Monitoring the anthocyanin accumulation during ripening shows the scion/rootstock combination can increase anthocyanin synthesis in the fruit, as well as vitamin C accumulation and acid degradation. Our results show that the rootstock genotype can exert important influences on citrus fruit quality by affecting gene expression in the scion. New insights into the molecular interactions between scion and rootstock may help unravel the systems through which rootstocks exert their influences on the regulatory networks in the scion, so as to influence relevant agronomic traits. This information should result in an improved rootstock breeding selection and definition of scion/rootstock combinations to enhance fruit quality traits. Full article

(This article belongs to the Special Issue Transcriptional Regulation during Fruit Development and Ripening)

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14 pages, 2209 KiB

Open AccessEditor’s ChoiceArticle

Differential Triggering of the Phenylpropanoid Biosynthetic Pathway Key Genes Transcription upon Cold Stress and Viral Infection in Tomato Leaves

by Polyxeni Pappi, Nikolaos Nikoloudakis, Dimitrios Fanourakis, Antonios Zambounis, Costas Delis and Georgios Tsaniklidis

Horticulturae 2021, 7(11), 448; https://doi.org/10.3390/horticulturae7110448 - 2 Nov 2021

Cited by 17 | Viewed by 2509

Abstract

Plants develop a plethora of defense strategies during their acclimation and interactions with various environmental stresses. Secondary metabolites play a pivotal role in the processes during stress acclimation, therefore deciphering their relevant responses exchange the interpretation of the underlying molecular mechanisms that may [...] Read more.

Plants develop a plethora of defense strategies during their acclimation and interactions with various environmental stresses. Secondary metabolites play a pivotal role in the processes during stress acclimation, therefore deciphering their relevant responses exchange the interpretation of the underlying molecular mechanisms that may contribute to improved adaptability and efficacy. In the current study, tomato plants were exposed to short-term cold stress (5 °C for 16 h) or inoculated (20 d) with either Cucumber Mosaic Virus (CMV) or Potato Virus Y (PVY). Responses were recorded via the assessments of leaf total phenolic (TP) content, total flavonoid (TF) levels, and phenylalanine ammonia-lyase (PAL) enzyme activity. The transcription of the gene families regulating the core phenylpropanoid biosynthetic pathway (PBP) at an early (PAL, cinnamic acid 4-hydroxylase, 4-coumarate-CoA ligase) or late (chalcone synthase and flavonol synthase) stage was also evaluated. The results showed that cold stress stimulated an increase in TP and TF contents, while PAL enzyme activity was also elevated compared to viral infection. Besides genes transcription of the enzymes involved in the core PBP was mostly induced by cold stress, whereas transcription of the genes regulating flavonoid biosynthesis was mainly triggered by viral infection. In conclusion, abiotic and biotic stressors induced differential regulation of the core PBP and flavonoid biosynthetic metabolism. Taking the above into consideration, our results highlight the complexity of tomato responses to diverse stimuli allowing for better elucidation of stress tolerance mechanisms at this crop. Full article

(This article belongs to the Special Issue Stress Biology of Horticultural Plants)

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14 pages, 1266 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Persistence and Transfer of Foodborne Pathogens to Sunflower and Pea Shoot Microgreens during Production in Soil-Free Cultivation Matrix

by Wenjun Deng, Gina M. Misra, Christopher A. Baker and Kristen E. Gibson

Horticulturae 2021, 7(11), 446; https://doi.org/10.3390/horticulturae7110446 - 2 Nov 2021

Cited by 8 | Viewed by 3059

Abstract

Microgreens are an emerging salad crop with properties similar to those of sprouted seeds and lettuce. This study aimed to determine bacterial pathogen persistence during microgreen cultivation and transfer from soil-free cultivation matrix (SFCM) to mature microgreens. Salmonella enterica subsp. enterica ser. Javiana [...] Read more.

Microgreens are an emerging salad crop with properties similar to those of sprouted seeds and lettuce. This study aimed to determine bacterial pathogen persistence during microgreen cultivation and transfer from soil-free cultivation matrix (SFCM) to mature microgreens. Salmonella enterica subsp. enterica ser. Javiana and Listeria monocytogenes were inoculated onto biostrate mats as well as peat SFCM and sampled (day 0). Next, sunflower and pea shoot seeds were planted (day 0) and grown in a controlled environment until the microgreen harvest (day 10). On day 10, SFCM and microgreens were sampled to determine the pathogen levels in the SFCM and the pathogen transfer to microgreens during production. Salmonella Javiana log CFU/g were significantly higher than L. monocytogenes in SFCM on day 10 in both planted and unplanted regions (p < 0.05). Significant differences in pathogen transfer (log CFU/g) were observed between the pea shoot and sunflower microgreens, regardless of the pathogen or SFCM type (p < 0.05). Meanwhile, pathogen transfer to the pea shoot and sunflower microgreens from the biostrate was 1.53 (95% CI: −0.75–3.81) and 5.29 (95% CI: 3.01–7.57) mean log CFU/g, respectively, and transfer from the peat was 0.00 (95% CI: −2.28–2.28) and 2.64 (95% CI: 0.36–4.92) mean log CFU/g, respectively. Results demonstrate that pathogen transfer to microgreens during production is influenced by SFCM and microgreen variety. Full article

(This article belongs to the Special Issue Pathogen Control Strategies for Pre-/Post-harvest of Horticultural Plants and the Application of the Plant-Derived Substances for Microbial Risk Management)

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12 pages, 693 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effect of Shading Nets on Yield, Leaf Biomass and Petiole Nutrients of a Muscat of Alexandria Vineyard Growing under Hyper-Arid Conditions

by Emilio Villalobos-Soublett, Gastón Gutiérrez-Gamboa, Claudio Balbontín, Andrés Zurita-Silva, Antonio Ibacache and Nicolás Verdugo-Vásquez

Horticulturae 2021, 7(11), 445; https://doi.org/10.3390/horticulturae7110445 - 2 Nov 2021

Cited by 6 | Viewed by 2259

Abstract

Background: Currently, viticulture is exposed to extreme weather fluctuations and global warming, thus the implementation of short-term adaptation strategies to mitigate climate change impacts will be of a wide importance for the sustainability and competitiveness of wine industry. This research aimed to [...] Read more.

Background: Currently, viticulture is exposed to extreme weather fluctuations and global warming, thus the implementation of short-term adaptation strategies to mitigate climate change impacts will be of a wide importance for the sustainability and competitiveness of wine industry. This research aimed to study the effect of shading nets on the viticultural performance of a Muscat of Alexandria vineyard growing under hyper-arid conditions. Methods: Three treatments were randomly arranged in the vineyard: (i) a control (without shading), (ii) a white shading net (25% of shading), and (iii) a black shading net (40% of shading). Subsequently, yield, vine vigor, berry composition, leaf biomass and petiole nutrient content were assessed. Results: Both shading nets decreased the incidence of solar radiation in vines. The application of white shading nets induced a high bunch weight and a higher number of berries per bunch than the black shading nets. Black shading nets increased pruning weight, decreased Ravaz index and induced a considerably accumulation of soluble solids in grapes. This treatment also decreased bunch weight and the number of berries per bunch, and increased rachis length compared to control. Black shading nets decreased Mg petiole content, leaf dry weight and leaf biomass at flowering compared to uncovered vines. Conclusions: Shading considerably affected the viticultural performance of Muscat of Alexandria vines growing under hyper-arid conditions, modifying yield, leaf biomass and petiole nutrients. Full article

(This article belongs to the Section Viticulture)

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13 pages, 569 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Sap Analysis: A Powerful Tool for Monitoring Plant Nutrition

by Eduardo Esteves, Guilherme Locatelli, Neus Alcon Bou and Rhuanito Soranz Ferrarezi

Horticulturae 2021, 7(11), 426; https://doi.org/10.3390/horticulturae7110426 - 22 Oct 2021

Cited by 10 | Viewed by 11795

Abstract

Horticultural crop production is moving towards an era of higher nutrient use efficiency since nutrient deficiencies can reduce plant growth, productivity, and quality, and overfertilization can cause environmental pollution. Rapid nutrient concentration diagnostic is essential to minimize the negative effects of Huanglongbing (HLB) [...] Read more.

Horticultural crop production is moving towards an era of higher nutrient use efficiency since nutrient deficiencies can reduce plant growth, productivity, and quality, and overfertilization can cause environmental pollution. Rapid nutrient concentration diagnostic is essential to minimize the negative effects of Huanglongbing (HLB) or citrus greening in citrus by providing the required nutrients before deficiency symptoms appear, reducing the impact of the disease on crop production. Sap analysis is an additional tool for fine-tuning nutrient applications in citrus. The main objective of this paper is to review the different methodologies and results obtained with sap analysis, considering its potential application in citrus production. Results from other crops show the pros and cons of using this tool. Substantial research has been conducted on vegetables and greenhouse crops, but few studies are available on perennial species such as citrus. Inconsistency in the extraction and analysis methods and the lack of specific sufficiency ranges for citrus open the path for further studies. Along with soil and leaf analyses, sap analysis is a complementary technique that can improve nutrient use efficiency in citrus production. Moreover, sap analysis has the potential to optimize fertilizer application, minimize environmental impacts and improve sustainability. Full article

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

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21 pages, 4406 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Impact of the Hydroponic Cropping System on Growth, Yield, and Nutrition of a Greek Sweet Onion (Allium cepa L.) Landrace

by Christos Mouroutoglou, Anastasios Kotsiras, Georgia Ntatsi and Dimitrios Savvas

Horticulturae 2021, 7(11), 432; https://doi.org/10.3390/horticulturae7110432 - 22 Oct 2021

Cited by 6 | Viewed by 7219

Abstract

Nerokremmydo of Zakynthos, a Greek landrace of sweet onion producing a large bulb, was experimentally cultivated in a glasshouse using aeroponic, floating, nutrient film technique, and aggregate systems, i.e., AER, FL, NFT, and AG, respectively. The aim of the experiment was to compare [...] Read more.

Nerokremmydo of Zakynthos, a Greek landrace of sweet onion producing a large bulb, was experimentally cultivated in a glasshouse using aeroponic, floating, nutrient film technique, and aggregate systems, i.e., AER, FL, NFT, and AG, respectively. The aim of the experiment was to compare the effects of these soilless culture systems (SCSs) on plant characteristics, including fresh and dry weight, bulb geometry, water use efficiency, tissue macronutrient concentrations, and uptake concentrations (UC), i.e., uptake ratios between macronutrients and water, during the main growth, bulbing, and maturation stages, i.e., 31, 62, and 95 days after transplanting. The plants grown in FL and AG yielded 7.87 and 7.57 kg m⁻², respectively, followed by those grown in AER (6.22 kg m⁻²), while those grown in NFT produced the lowest yield (5.20 kg m⁻²). The volume of nutrient solution (NS) consumed per plant averaged 16.87 L, with NFT plants recording the least consumption. The SCS affected growth rate of new roots and “root mat” density that led to corresponding nutrient uptake differences. In NFT, reduced nutrient uptake was accompanied by reduced water consumption. The SCS and growth stage strongly affected tissue N, P, K, Ca, Mg, and S mineral concentrations and the respective UC. The UC of N and Κ followed a decreasing trend, while that of Mg decreased only until bulbing, and the UC of the remainder of the macronutrients increased slightly during the cropping period. The UC can be used as a sound basis to establish NS recommendations for cultivation of this sweet onion variety in closed SCSs. Full article

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

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12 pages, 3998 KiB

Open AccessEditor’s ChoiceArticle

Analysis of Light-Independent Anthocyanin Accumulation in Mango (Mangifera indica L.)

by Bin Shi, Hongxia Wu, Bin Zheng, Minjie Qian, Aiping Gao and Kaibing Zhou

Horticulturae 2021, 7(11), 423; https://doi.org/10.3390/horticulturae7110423 - 21 Oct 2021

Cited by 13 | Viewed by 2940

Abstract

Light dependent anthocyanin accumulation contributes to the red pigmentation of the fruit skin of mango (Mangifera indica L.). Light-independent pigmentation has also been reported, but remains poorly characterized. In this study, the pigmentation patterns in the skin of two red mango cultivars, [...] Read more.

Light dependent anthocyanin accumulation contributes to the red pigmentation of the fruit skin of mango (Mangifera indica L.). Light-independent pigmentation has also been reported, but remains poorly characterized. In this study, the pigmentation patterns in the skin of two red mango cultivars, ‘Ruby’ and ‘Sensation’, were evaluated. Metabolomic profiling revealed that quercetin-3-O-glucoside, cyanidin-3-O-galactoside, procyanidin B1, and procyanidin B3 are the predominant flavonoid compounds in the skin of ‘Ruby’ and ‘Sensation’ fruit. Young fruit skin mainly accumulates flavonol and proanthocyanidin, while anthocyanin is mainly accumulated in the skin of mature fruit. Bagging treatment inhibited the biosynthesis of flovonol and anthocyanin, but promoted the accumulation of proanthocyanidin. Compared with ‘Sensation’, matured ‘Ruby’ fruit skin showed light red pigmentation at 120 days after full bloom (DAFB), showing a light-independent anthocyanin accumulation pattern. However, the increase of anthocyanin concentration, and the expression of key anthocyanin structural and regulatory genes MiUFGT1, MiUFGT3, and MiMYB1 in the skin of bagged ‘Ruby’ fruit versus ‘Sensation’ at 120 DAFB was very limited. There was no mutation in the crucial elements of MiMYB1 promoter between ‘Ruby’ and ‘Sensation’. We hypothesize that the light-independent anthocyanin accumulation in the skin of mature ‘Ruby’ fruit is regulated by plant hormones, and that ‘Ruby’ can be used for breeding of new more easily pigmented red mango cultivars. Full article

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

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11 pages, 2507 KiB

Open AccessEditor’s ChoiceArticle

Water Stress in Dwarfing Cherry Rootstocks: Increased Carbon Partitioning to Roots Facilitates Improved Tolerance of Drought

by Will Wheeler, Brent Black and Bruce Bugbee

Horticulturae 2021, 7(11), 424; https://doi.org/10.3390/horticulturae7110424 - 21 Oct 2021

Cited by 3 | Viewed by 1665

Abstract

Cherry orchards are transitioning to high-density plantings and dwarfing rootstocks to maximize production, but the response of these rootstocks to drought stress is poorly characterized. We used a 16-container, automated lysimeter system to apply repeated water stress to ungrafted Krymsk^® 5 and [...] Read more.

Cherry orchards are transitioning to high-density plantings and dwarfing rootstocks to maximize production, but the response of these rootstocks to drought stress is poorly characterized. We used a 16-container, automated lysimeter system to apply repeated water stress to ungrafted Krymsk^® 5 and 6 rootstocks during two growing cycles. Drought stress was imposed by withholding irrigation until the daily transpiration rate of each tree was 25% and 30% of the unstressed rate during the first trial and second trial, respectively. After this point was reached, the root-zone water status was restored to field capacity. Whole-tree transpiration measurements were supplemented with leaf-level gas-exchange measurements. Krymsk^® 6 had a higher rate of photosynthesis, more vigorous vegetative growth and less conservative stomatal regulation during incipient drought than Krymsk^® 5. At harvest, carbon partitioning to roots was greater in Krymsk^® 6 than Krymsk^® 5. The conservative rate of water use in Krymsk^® 5 could be a function of greater stomatal control or reduced carbon partitioning to roots, which thereby limited transpiration rates. Further studies are needed to confirm that these results are applicable to trees grown using a common grafted scion under field conditions. Full article

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14 pages, 1770 KiB

Open AccessEditor’s ChoiceArticle

Impact of Drought and Flooding on Alkaloid Production in Annona crassiflora Mart

by Ana Beatriz Marques Honório, Iván De-la-Cruz-Chacón, Mariano Martínez-Vázquez, Magali Ribeiro da Silva, Felipe Girotto Campos, Bruna Cavinatti Martin, Gustavo Cabral da Silva, Carmen Sílvia Fernandes Boaro and Gisela Ferreira

Horticulturae 2021, 7(10), 414; https://doi.org/10.3390/horticulturae7100414 - 19 Oct 2021

Cited by 9 | Viewed by 2491

Abstract

The Brazilian Cerrado is the second largest Brazilian biome. In recent decades, a reduction in rainfall has indicated an extension of the dry season. Among the many native species of the Cerrado of the Annonaceae family and used in folk medicine, Annona crassiflora [...] Read more.

The Brazilian Cerrado is the second largest Brazilian biome. In recent decades, a reduction in rainfall has indicated an extension of the dry season. Among the many native species of the Cerrado of the Annonaceae family and used in folk medicine, Annona crassiflora Mart. has fruits of high nutritional value and its by-products are sources of bioactive compounds, such as alkaloids. The aim of the study was to investigate how water stress impacts the production of alkaloids. The study was carried out in a nursery, and the knowledge was flood, field capacity and drought. Gas exchange, chlorophyll a fluorescence, antioxidant enzymes, total soluble sugars, starch, reducing sugars, sucrose, total alkaloids and liriodenine were analyzed. We observed that plants subjected to drought had an increase in the production of total alkaloids and liriodenine, without a reduction in photosynthetic metabolism. Plants kept under drought and flood conditions dissipated higher peroxidase activity, while catalase was higher in flooded plants. Starch showed the highest concentration in flooding plants without differing from drought plants; the lowest trehalose concentrations were found in both drought and flooding plants. The drought stimulated the synthesis of total alkaloids and liriodenine without reducing the primary metabolism, which suggests adaptation to Cerrado conditions. Full article

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

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25 pages, 850 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Moringa oleifera Lam.: A Phytochemical and Pharmacological Overview

by Attilio Anzano, Mohammad Ammar, Marina Papaianni, Laura Grauso, Mohammed Sabbah, Rosanna Capparelli and Virginia Lanzotti

Horticulturae 2021, 7(10), 409; https://doi.org/10.3390/horticulturae7100409 - 16 Oct 2021

Cited by 11 | Viewed by 12132

Abstract

Moringa oleifera Lam. is a fast-growing and drought-resistant tree of the Moringaceae family. The tree is known with some common names: miracle, ben oil, drumstick, horseradish or simply moringa. The plant grows in a variety of environments including harsh conditions. The plant has [...] Read more.

Moringa oleifera Lam. is a fast-growing and drought-resistant tree of the Moringaceae family. The tree is known with some common names: miracle, ben oil, drumstick, horseradish or simply moringa. The plant grows in a variety of environments including harsh conditions. The plant has a high content of phytonutrients, being used as natural integrators to cure malnutrition. Phytochemical studies of plant organs showed the plant as a rich source of primary and secondary metabolites belonging to different classes of organic compounds. Pharmacological studies confirmed the use of the plant to cure several diseases and to possess nutraceutical properties. This review is aimed to contribute to the knowledge of M. oleifera by providing its plant description, phytochemistry and pharmacology. Full article

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

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16 pages, 5886 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Identification and Bioinformatics Analysis of Auxin Response Factor Genes in Highbush Blueberry

by Yu Zong, Lili Gu, Zhuli Shen, Haiting Kang, Yongqiang Li, Fanglei Liao, Lishan Xu and Weidong Guo

Horticulturae 2021, 7(10), 403; https://doi.org/10.3390/horticulturae7100403 - 15 Oct 2021

Cited by 5 | Viewed by 2029

Abstract

Auxin response factors (ARFs) are a transcription factor family that regulates the expression of auxin phase-responsive genes. Here, we performed a genome-wide investigation of the tetraploid blueberry (Vaccinium corymbosum cv. ‘Draper’) genome sequence. Physical and chemical properties, phylogenetic evolution, gene structure, conservative [...] Read more.

Auxin response factors (ARFs) are a transcription factor family that regulates the expression of auxin phase-responsive genes. Here, we performed a genome-wide investigation of the tetraploid blueberry (Vaccinium corymbosum cv. ‘Draper’) genome sequence. Physical and chemical properties, phylogenetic evolution, gene structure, conservative motifs, chromosome location, and cis-acting elements of blueberry ARF genes were comprehensively evaluated. A total of 70 blueberry ARF genes (VcARF) were found in its genome, which could be divided into six subfamilies. VcARF genes were unevenly distributed on 40 chromosomes and were observed to encode protein sequences ranging in length from 162 to 1117 amino acids. Their exon numbers range from 2 to 22. VcARF promoter regions contain multiple functional domains associated with light signaling, aerobic metabolism, plant hormones, stress, and cell cycle regulation. More family members of VcARF genes were discovered in blueberry than in previously studied plants, likely because of the occurrence of whole-genome duplication and/or tandem duplication. VcARF expression patterns were analyzed at different stages of fruit development, and VcARF3, VcARF4, VcARF14, VcARF37, and VcARF52 were observed to play important roles. VcARF3 and VcARF4 appeared to function as repressors, while VcARF14 acted as an essential factor in fruit firmness differences between firm and soft flesh cultivars. Full article

(This article belongs to the Special Issue Genetics and Breeding of Fruit Trees)

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9 pages, 1921 KiB

Open AccessEditor’s ChoiceArticle

Variability of Polyphenolic Compounds and Biological Activities among Perilla frutescens var. crispa Genotypes

by Hyun Ju Ju, Kyeoung Cheol Kim, Heekyu Kim, Ju-Sung Kim and Tae Kyung Hyun

Horticulturae 2021, 7(10), 404; https://doi.org/10.3390/horticulturae7100404 - 15 Oct 2021

Cited by 12 | Viewed by 2257

Abstract

Perilla frutescens var. crispa (Pfc) of the family Lamiaceae is used as a medicinal plant due to its pharmacological properties. Although Pfc is an important resource for the medical nutrition industry, the variability in phytonutrients and biological activities among genotypes of Pfc is [...] Read more.

Perilla frutescens var. crispa (Pfc) of the family Lamiaceae is used as a medicinal plant due to its pharmacological properties. Although Pfc is an important resource for the medical nutrition industry, the variability in phytonutrients and biological activities among genotypes of Pfc is not well understood. The effects of genotype on the phytochemical composition, antioxidant activities, antimelanogenic principles, and anti-inflammatory effects of Pfc were determined using eight Pfc genotypes. Using HPLC analysis, we identified 30 polyphenolic compounds from Pfc, although variation was observed in the polyphenolic composition of Pfc genotypes. Pfc 5 exhibited antimelanogenic activity in B16F10 melanoma cells via inhibition of tyrosinase activity. In addition, Pfc 2 strongly inhibited lipopolysaccharide-induced nitric oxide production through translational downregulation of inducible NOS in RAW264 murine macrophages. Taken together, the results of our study reveal the significant impacts of genotype on phytonutrients and biological activities. This finding will assist in the breeding and genetic engineering of Pfc in order to meet future phytonutrition and health challenges. Full article

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

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14 pages, 3467 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Identification of the 1-Aminocyclopropane-1-carboxylic Acid Synthase (ACS) Genes and Their Possible Role in Sand Pear (Pyrus pyrifolia) Fruit Ripening

by Jing-Guo Zhang, Wei Du, Jing Fan, Xiao-Ping Yang, Qi-Liang Chen, Ying Liu, Hong-Ju Hu and Zheng-Rong Luo

Horticulturae 2021, 7(10), 401; https://doi.org/10.3390/horticulturae7100401 - 14 Oct 2021

Cited by 2 | Viewed by 2023

Abstract

Ethylene production is negatively associated with storage life in sand pear (Pyrus pyrifolia Nakai), particularly at the time of fruit harvest. 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is the rate-limiting enzyme in ethylene biosynthesis and is considered to be important for fruit storage life. [...] Read more.

Ethylene production is negatively associated with storage life in sand pear (Pyrus pyrifolia Nakai), particularly at the time of fruit harvest. 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is the rate-limiting enzyme in ethylene biosynthesis and is considered to be important for fruit storage life. However, the candidate ACS genes and their roles in sand pear remain unclear. The present study identified 13 ACS genes from the sand pear genome. Phylogenetic analysis categorized these ACS genes into four subgroups (type I, type II, type III and putative AAT), and indicated a close relationship between sand pear and Chinese white pear (P. bretschneideri). According to the RNA-seq data and qRT-PCR analysis, PpyACS1, PpyACS2, PpyACS3, PpyACS8, PpyACS9, PpyACS12 and PpyACS13 were differently expressed in climacteric and non-climacteric-type pear fruits, ‘Ninomiyahakuri’ and ‘Eli No.2’, respectively, during fruit ripening. In addition, the expressions of PpyACS2, PpyACS8, PpyACS12 and PpyACS13 were found to be associated with system 1 of ethylene production, while PpyACS1, PpyACS3, and PpyACS9 were found to be associated with system 2, indicating that these ACS genes have different roles in ethylene biosynthesis during fruit development. Overall, our study provides fundamental knowledge on the characteristics of the ACS gene family in sand pear, in addition to their possible roles in fruit ripening. Full article

(This article belongs to the Special Issue Genetics and Breeding of Fruit Trees)

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14 pages, 1762 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Mycorrhiza-and Trichoderma-Mediated Elicitation of Secondary Metabolism and Modulation of Phytohormone Profile in Tomato Plants

by Giusy Iula, Begoña Miras-Moreno, Luigi Lucini and Marco Trevisan

Horticulturae 2021, 7(10), 394; https://doi.org/10.3390/horticulturae7100394 - 12 Oct 2021

Cited by 6 | Viewed by 3472

Abstract

Arbuscular mycorrhiza and Trichoderma are well-known beneficial fungi whose plant growth promotion and defense elicitation effects are known. However, the molecular and biochemical processes underlying the beneficial effects of these priming microorganisms have not been fully elucidated yet. On this basis, the present [...] Read more.

Arbuscular mycorrhiza and Trichoderma are well-known beneficial fungi whose plant growth promotion and defense elicitation effects are known. However, the molecular and biochemical processes underlying the beneficial effects of these priming microorganisms have not been fully elucidated yet. On this basis, the present work aimed to use metabolomics to dissect comprehensively the modulation of secondary metabolism induced by mycorrhiza and Trichoderma, using tomato as a model plant. To this aim, either mycorrhiza or Trichoderma were applied to tomato roots at transplanting using a commercial formulation and then harvested once the mutualistic relationship was well established. Shoots were analyzed using an MS-based untargeted metabolomics approach, and differential metabolites identified by multivariate statistics were subjected to pathway analysis. Together with promoting plant growth, the treatments induced a broad molecular reprogramming with the phenylpropanoid biosynthetic pathway (including defense phenolics like coumarins and glycosylated anthocyanins) being strongly elicited. An accumulation of auxins, cytokinins, and jasmonate (especially after treatment with Trichoderma) could be observed concerning phytohormone profiles. Overall, the broad and distinctive effects triggered by mycorrhiza and Trichoderma in tomato secondary metabolism supported both plant growth promotion and immunity. Full article

(This article belongs to the Special Issue Biostimulants and Plant Elicitors to Mitigate the Effect of Biotic and Abiotic Stress)

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21 pages, 1437 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Plant Tolerance to Drought Stress in the Presence of Supporting Bacteria and Fungi: An Efficient Strategy in Horticulture

by Agnieszka Hanaka, Ewa Ozimek, Emilia Reszczyńska, Jolanta Jaroszuk-Ściseł and Maria Stolarz

Horticulturae 2021, 7(10), 390; https://doi.org/10.3390/horticulturae7100390 - 11 Oct 2021

Cited by 35 | Viewed by 6593

Abstract

Increasing temperature leads to intensive water evaporation, contributing to global warming and consequently leading to drought stress. These events are likely to trigger modifications in plant physiology and microbial functioning due to the altered availability of nutrients. Plants exposed to drought have developed [...] Read more.

Increasing temperature leads to intensive water evaporation, contributing to global warming and consequently leading to drought stress. These events are likely to trigger modifications in plant physiology and microbial functioning due to the altered availability of nutrients. Plants exposed to drought have developed different strategies to cope with stress by morphological, physiological, anatomical, and biochemical responses. First, visible changes influence plant biomass and consequently limit the yield of crops. The presented review was undertaken to discuss the impact of climate change with respect to drought stress and its impact on the performance of plants inoculated with plant growth-promoting microorganisms (PGPM). The main challenge for optimal performance of horticultural plants is the application of selected, beneficial microorganisms which actively support plants during drought stress. The most frequently described biochemical mechanisms for plant protection against drought by microorganisms are the production of phytohormones, antioxidants and xeroprotectants, and the induction of plant resistance. Rhizospheric or plant surface-colonizing (rhizoplane) and interior (endophytic) bacteria and fungi appear to be a suitable alternative for drought-stress management. Application of various biopreparations containing PGPM seems to provide hope for a relatively cheap, easy to apply and efficient way of alleviating drought stress in plants, with implications in productivity and food condition. Full article

(This article belongs to the Special Issue Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants)

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12 pages, 299 KiB

Open AccessEditor’s ChoiceArticle

Comparison between Fermentation and Ultrasound-Assisted Extraction: Which Is the Most Efficient Method to Obtain Antioxidant Polyphenols from Sambucus nigra and Punica granatum Fruits?

by Luana Beatriz dos Santos Nascimento, Antonella Gori, Ilaria Degano, Alessandro Mandoli, Francesco Ferrini and Cecilia Brunetti

Horticulturae 2021, 7(10), 386; https://doi.org/10.3390/horticulturae7100386 - 9 Oct 2021

Cited by 7 | Viewed by 2388

Abstract

Fruit extracts of Sambucus nigra L. (elderberry) and Punica granatum L. (pomegranate) have several applications in nutraceutical, cosmetics, and pharmaceutical industries thanks to their richness in antioxidant polyphenols, whose composition changes with the extraction method applied. We aimed to compare the efficiency of [...] Read more.

Fruit extracts of Sambucus nigra L. (elderberry) and Punica granatum L. (pomegranate) have several applications in nutraceutical, cosmetics, and pharmaceutical industries thanks to their richness in antioxidant polyphenols, whose composition changes with the extraction method applied. We aimed to compare the efficiency of the fermentation extraction, recently applied by industries, with the ultrasound-assisted extraction–UAE, a well-known and efficient technique, on the yield of antioxidant polyphenols from elderberry fruits and pomegranate fruit-peels. Extracts were obtained by both methods, analyzed by high-performance liquid chromatography (HPLC) and the antioxidant capacities were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Hydroxyl Radical Scavenging (HRS) assays. The main compounds detected in elderberry were caffeoyl and quercetin derivatives, present in higher amounts in UAE extracts. In pomegranate, punicalagin were the main constituents, also detected in higher contents in the UAE extracts compared to fermented ones. The UAE was more suitable for extracting anthocyanins from pomegranate. In addition, higher antioxidant capacities were observed in UAE extracts, possibly due to their richness in polyphenols. Therefore, despite the recent wide applicability and the good performance of the fermentation process, the UAE may be considered more efficient for the extraction of polyphenols from S. nigra and P. granatum fruits and may be used to obtain polyphenolic antioxidant extracts to be applied by several industries. Full article

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

23 pages, 3912 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of 130 Eggplant (Solanum melongena L.) Genotypes for Future Breeding Program Based on Qualitative and Quantitative Traits, and Various Genetic Parameters

by Md. Shalim Uddin, Masum Billah, Rozina Afroz, Sajia Rahman, Nasrin Jahan, Md. Golam Hossain, Shamim Ara Bagum, Md. Sorof Uddin, Abul Bashar Mohammad Khaldun, Md. Golam Azam, Neelima Hossain, Mohammad Abdul Latif Akanda, Majid Alhomrani, Ahmed Gaber and Akbar Hossain

Horticulturae 2021, 7(10), 376; https://doi.org/10.3390/horticulturae7100376 - 8 Oct 2021

Cited by 17 | Viewed by 3857

Abstract

Eggplant is an essential widespread year-round fruit vegetable. This study was conducted using 130 local germplasm of brinjal to select diverse parents based on the multiple traits selection index for the future breeding program. This selection was performed focusing on 14 qualitative and [...] Read more.

Eggplant is an essential widespread year-round fruit vegetable. This study was conducted using 130 local germplasm of brinjal to select diverse parents based on the multiple traits selection index for the future breeding program. This selection was performed focusing on 14 qualitative and 10 quantitative traits variation and genetic parameters namely, phenotypic and genotypic variance (PV and GV) and genotypic and phenotypic coefficients of variation (GCV and PCV), broad-sense heritability (hBS), genetic advance, traits association, genotype by trait biplot (G × T), heatmap analysis and multi-trait index based on factor analysis and genotype-ideotype distance (MGIDI). Descriptive statistics and analysis of variance revealed a wide range of variability for morpho-physiological traits. Estimated hBS for all the measured traits ranged from 10.6% to 93%, indicating that all the traits were highly inheritable. Genetic variances were low to high for most morpho-physiological traits, indicating complex genetic architecture. Yield per plant was significantly correlated with fruit diameter, fruits per plant, percent fruits infestation by brinjal shoot and fruit borer, and fruit weight traits indicating that direct selection based on fruit number and fruit weight might be sufficient for improvement of other traits. The first two principal components (PCs) explained about 81.27% of the total variation among lines for 38 brinjal morpho-physiological traits. Genotype by trait (G × T) biplot revealed superior genotypes with combinations of favorable traits. The average genetic distance was 3.53, ranging from 0.25 to 20.01, indicating high levels of variability among the germplasm. The heat map was also used to know the relationship matrix among all the brinjal genotypes. MGIDI is an appropriate method of selection based on multiple trait information. Based on the fourteen qualitative and ten quantitative traits and evaluation of various genetic parameters, the germplasm G80, G54, G66, and G120 might be considered as best parents for the future breeding program for eggplant improvement. Full article

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

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17 pages, 3548 KiB

Open AccessEditor’s ChoiceArticle

Effect of Foliar Supplied PGRs on Flower Growth and Antioxidant Activity of African Marigold (Tagetes erecta L.)

by Sadia Sadique, Muhammad Moaaz Ali, Muhammad Usman, Mahmood Ul Hasan, Ahmed F. Yousef, Muhammad Adnan, Shaista Gull and Silvana Nicola

Horticulturae 2021, 7(10), 378; https://doi.org/10.3390/horticulturae7100378 - 8 Oct 2021

Cited by 5 | Viewed by 2460

Abstract

Marigold is one of the commercially exploited flowering crops that belongs to the family Asteraceae. The production of economical yield and better quality of marigold flowers requires proper crop management techniques. Crop regulation is an important technique to make the marigold production profitable. [...] Read more.

Marigold is one of the commercially exploited flowering crops that belongs to the family Asteraceae. The production of economical yield and better quality of marigold flowers requires proper crop management techniques. Crop regulation is an important technique to make the marigold production profitable. This can be done by adopting application of plant growth regulators (PGRs). The present study was designed to investigate the effect of PGRs on flowering and antioxidant activity of two cultivars of African marigold (Tagetes erecta L.) viz. “Pusa Narangi Gainda” (hereinafter referred to as Narangi) and “Pusa Basanthi Gainda” (hereafter referred to as Basanthi). Plants were sprayed with abscisic acid (ABA), N-acetyl thiazolidine (NAD), gibberellic acid (GA₃), salicylic acid (SA), indole-3-butyric acid (IBA) and oxalic acid (OA) at the concentrations of 100, 150, 250, 300 and 800 mg·L⁻¹, each. Results revealed that the plants treated with 500–600 mg·L⁻¹ IBA exhibited maximum increase in floral diameter (34–51%). The use of 500–550 mg·L⁻¹ IBA exhibited maximal enhancement in flower fresh weight (21–92%). The exogenously applied OA significantly (p ≤ 0.05) improved flower dry weight, total phenolic contents, total flavonoid contents and reducing power ability of marigold plants. Overall, “Narangi” performed better than “Basanthi”, in terms of flowering and antioxidant activity. Conclusively, the results suggest that foliar application of PGRs favors flowering and antioxidant activity of African marigold. Full article

(This article belongs to the Special Issue Trends in Ornamental Plant Production)

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12 pages, 2742 KiB

Open AccessEditor’s ChoiceArticle

Dehydrins and Soluble Sugars Involved in Cold Acclimation of Rosa wichurana and Rose Cultivar ‘Yesterday’

by Lin Ouyang, Leen Leus, Ellen De Keyser and Marie-Christine Van Labeke

Horticulturae 2021, 7(10), 379; https://doi.org/10.3390/horticulturae7100379 - 8 Oct 2021

Cited by 5 | Viewed by 1518

Abstract

Rose is the most economically important ornamental plant. However, cold stress seriously affects the survival and regrowth of garden roses in northern regions. Cold acclimation was studied using two genotypes (Rosa wichurana and R. hybrida ‘Yesterday’) selected from a rose breeding program. [...] Read more.

Rose is the most economically important ornamental plant. However, cold stress seriously affects the survival and regrowth of garden roses in northern regions. Cold acclimation was studied using two genotypes (Rosa wichurana and R. hybrida ‘Yesterday’) selected from a rose breeding program. During the winter season (November to April), the cold hardiness of stems, soluble sugar content, and expression of dehydrins and the related key genes in the soluble sugar metabolism were analyzed. ‘Yesterday’ is more cold-hardy and acclimated faster, reaching its maximum cold hardiness in December. R. wichurana is relatively less cold-hardy, only reaching its maximum cold hardiness in January after prolonged exposure to freezing temperatures. Dehydrin transcripts accumulated significantly during November–January in both genotypes. Soluble sugars are highly involved in cold acclimation, with sucrose and oligosaccharides significantly correlated with cold hardiness. Sucrose occupied the highest proportion of total soluble sugars in both genotypes. During November–January, downregulation of RhSUS was found in both genotypes, while upregulation of RhSPS was observed in ‘Yesterday’ and upregulation of RhINV2 was found in R. wichurana. Oligosaccharides accumulated from November to February and decreased to a significantly low level in April. RhRS6 had a significant upregulation in December in R. wichurana. This study provides insight into the cold acclimation mechanism of roses by combining transcription patterns with metabolite quantification. Full article

(This article belongs to the Special Issue Breeding, Genetics and Genomics of Ornamental Plants)

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17 pages, 1903 KiB

Open AccessEditor’s ChoiceArticle

Light Quality Environment and Photomorphological Responses of Young Olive Trees

by Federico J. Ladux, Eduardo R. Trentacoste, Peter S. Searles and M. Cecilia Rousseaux

Horticulturae 2021, 7(10), 369; https://doi.org/10.3390/horticulturae7100369 - 6 Oct 2021

Cited by 6 | Viewed by 2679

Abstract

Tree densities have increased greatly in olive orchards over the last few decades. In many annual crop species, increased density reduces the horizontal red/far-red (R/FR) and blue/green (B/G) ratios during canopy development even before direct shading occurs, and such changes are known to [...] Read more.

Tree densities have increased greatly in olive orchards over the last few decades. In many annual crop species, increased density reduces the horizontal red/far-red (R/FR) and blue/green (B/G) ratios during canopy development even before direct shading occurs, and such changes are known to alter plant morphology. This study with olive trees evaluated: (1) whether the leaf area index (LAI) of neighboring trees modifies the light quality environment prior to a tree being directly shaded and (2) the potential morphological responses of three olive cultivars to changes in light quality. Increasing LAI using different spatial arrangements of potted, three-year-old trees reduced the horizontal R/FR ratio more than that of the B/G ratio. Cultivar-specific responses to low R/FR ratio were observed for individual leaf area and aboveground/belowground biomass ratio using laterally positioned FR mirrors or green fences. No statistically significant responses were detected in response to green vegetation fences that reduced both horizontal R/FR and B/G ratios, but a cluster analysis grouped together the overall morphological responses to both FR mirrors and green fences. These results in olive trees suggest that cultivar differences in response to light quality may be relevant for understanding adaptation to dense orchards and identifying cultivars best suited to them. Full article

(This article belongs to the Special Issue Precision Management of Fruit Trees)

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16 pages, 1023 KiB

Open AccessEditor’s ChoiceArticle

“Oh, You Shouldn’t Have!” Understanding Key Factors Impacting Cut Flowers Gifting Preferences in Germany

by Meike Rombach, David L. Dean, Nicole J. Olynk Widmar and Vera Bitsch

Horticulturae 2021, 7(10), 368; https://doi.org/10.3390/horticulturae7100368 - 6 Oct 2021

Cited by 4 | Viewed by 2449

Abstract

Cut flower gifting preferences are relatively unexplored in Germany. This study proposes a model that investigates the impact of attitudinal, experiential, and socio-demographic factors on the cut flower gifting preferences of German consumers. For this purpose, an online survey with a representative sample [...] Read more.

Cut flower gifting preferences are relatively unexplored in Germany. This study proposes a model that investigates the impact of attitudinal, experiential, and socio-demographic factors on the cut flower gifting preferences of German consumers. For this purpose, an online survey with a representative sample of 978 German residents was conducted. Partial least squares structural equation modelling shows that active and passive engagement with plants and nature positively impact cut flower giving preferences through cut flower knowledge, cut flower fondness, and perceived versatility of cut flowers. For German women and men, the largest driver of cut flower giving preferences is the versatility of cut flowers. For women, cut flower fondness is the second largest driver of cut flower gifting preferences, whereas for men subjective knowledge was the second largest driver. Other socio-demographic factors (age, income, education) were not found to impact cut flower giving preferences. Full article

(This article belongs to the Section Horticultural Economics, Policy, Business Management and Marketing)

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10 pages, 258 KiB

Open AccessEditor’s ChoiceArticle

The Dominance of Chitosan Hydrochloride over Modern Natural Agents or Basic Substances in Efficacy against Phytophthora infestans, and Its Safety for the Non-Target Model Species Eisenia fetida

by Martin Žabka and Roman Pavela

Horticulturae 2021, 7(10), 366; https://doi.org/10.3390/horticulturae7100366 - 5 Oct 2021

Cited by 6 | Viewed by 1738

Abstract

Growing pressure to reduce the environmental pesticide burden has the greatest impact on agriculture and crop protection. There is an enormous increase in the demand for research on new, effective, naturally based agents that do not pose an environmental risk. Phytophthora infestans is [...] Read more.

Growing pressure to reduce the environmental pesticide burden has the greatest impact on agriculture and crop protection. There is an enormous increase in the demand for research on new, effective, naturally based agents that do not pose an environmental risk. Phytophthora infestans is one of the most destructive phytopathogens, especially in cases where synthetic fungicides are not allowed. This paper describes the high efficacy and safety of the natural polymer chitosan under in vitro and in vivo conditions and its dominance over other natural agents or products. Chitosan demonstrated the highest efficacy against P. infestans. A concentration of 0.2–0.4% was highly effective. The protective effect of chitosan was 99.3% in natural conditions. Direct activity, equivalent to synthetic fungicides (MIC50 0.293 mg/mL), was confirmed. Chitosan was rated non-toxic to useful non-target species. We promote further chitosan expansion within legislation and implementation of chitosan as a safe substance that could reduce the pesticide burden, particularly in eco-friendly plant protection and production of non-harmful foods. Full article

(This article belongs to the Special Issue Biological Control of Pre- and Postharvest Fungal Diseases)

17 pages, 3001 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Morphological, Physiological, and Biochemical Responses of Zinnia to Drought Stress

by Stefania Toscano and Daniela Romano

Horticulturae 2021, 7(10), 362; https://doi.org/10.3390/horticulturae7100362 - 4 Oct 2021

Cited by 12 | Viewed by 3365

Abstract

Bedding plants in the nursery phase are often subject to drought stress because of the small volume of the containers and the hydraulic conductivity of organic substrates used. To analyse the morphological, physiological, and enzymatic responses of zinnia (Zinnia elegans L.) plants [...] Read more.

Bedding plants in the nursery phase are often subject to drought stress because of the small volume of the containers and the hydraulic conductivity of organic substrates used. To analyse the morphological, physiological, and enzymatic responses of zinnia (Zinnia elegans L.) plants at different irrigation levels, four treatments were performed: irrigated at 100% (100% field capacity, FC); light deficit irrigation (75% FC), medium deficit irrigation (50% FC), and severe deficit irrigation (25% FC). The growth of zinnia was significantly influenced by drought stress treatments. Different morphological parameters (dry biomass, leaf number, root to shoot ratio (R/S)) were modified only in the more severe drought stress treatment (25% FC). The stomata density increased in 50% FC and 25% FC, while the stomata size was reduced in 25% FC. The net photosynthesis, stomatal conductance, and transpiration were reduced in 50% FC and 25% FC. The relative water content (RWC) was reduced in 25% FC. Severe drought stress (25% FC) increased proline content up to seven-fold. Catalase (CAT), peroxidase (GPX), and superoxide dismutase (SOD) activity significantly increased in 50% FC and 25% FC. Principal component analysis (PCA) showed that the morphological and physiological parameters were mostly associated with the 100% FC and 75% FC treatments of the biplot, whereas the stomata density, R/S ratio, and antioxidant enzymes (GPX, CAT) were associated with 50% FC, and proline and DPPH were associated with 25% FC, respectively. Full article

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

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19 pages, 8049 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Continuous Monitoring of Olive Fruit Growth by Automatic Extensimeter in Response to Vapor Pressure Deficit from Pit Hardening to Harvest

by Arash Khosravi, Matteo Zucchini, Veronica Giorgi, Adriano Mancini and Davide Neri

Horticulturae 2021, 7(10), 349; https://doi.org/10.3390/horticulturae7100349 - 30 Sep 2021

Cited by 7 | Viewed by 2085

Abstract

Recently, several studies on olive fruit growth have focused on circadian monitoring as an important orchard management tool. The olive fruit growth trend is described by double sigmoid model with four growth phases, where the third phase spans from the end of pit [...] Read more.

Recently, several studies on olive fruit growth have focused on circadian monitoring as an important orchard management tool. The olive fruit growth trend is described by double sigmoid model with four growth phases, where the third phase spans from the end of pit hardening to initial fruit maturation, and the last phase includes olive maturation up to fruit drop. Environmental factors play an important role in fruit growth, with vapor pressure deficit (VPD) being a keystone factor. Our experiment was designed to hourly monitor olive (Olea europaea L. cv. ‘Frantoio’) fruit transversal diameter from approximately initial pit hardening (II Phase), extension (III Phase) until harvest time (IV Phase) in the attempt to determine whether fruit growth dynamically responds to environmental variables such as diurnal VPD change in different stages of fruit development. Automatic extensimeters were applied in open field and VPD was calculated from data of our weather station. Throughout the experiment period, the circadian model of fruit growth showed two steps: shrinkage and expansion. Almost in all days of the third phase of fruit growth, daily response of transversal diameter to VPD formed complete clockwise hysteresis loops. During the fourth phase of fruit growth, with increasing fruit maturation, the complete clockwise hysteresis loop experienced some abnormality. At the fourth stage of fruit growth there were incomplete and partial clockwise hysteresis loops. We conclude that hysteresis can be employed to detect the shift between the end of the third phase (cell expansion) and the beginning of the fourth phase (fruit maturation) of fruit growth. The disappearance of the complete clockwise hysteresis loop and the substitution with incomplete, or partial clockwise hysteresis loops was observable only in the fourth stage of fruit growth. These results can be valuable for any smart fruit management of olive fruit production. Full article

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17 pages, 1467 KiB

Open AccessEditor’s ChoiceArticle

Exogenous Application of Chitosan Alleviate Salinity Stress in Lettuce (Lactuca sativa L.)

by Geng Zhang, Yuanhua Wang, Kai Wu, Qing Zhang, Yingna Feng, Yu Miao and Zhiming Yan

Horticulturae 2021, 7(10), 342; https://doi.org/10.3390/horticulturae7100342 - 24 Sep 2021

Cited by 22 | Viewed by 3385

Abstract

Soil salinity is one of the major factors that affect plant growth and decrease agricultural productivity worldwide. Chitosan (CTS) has been shown to promote plant growth and increase the abiotic stress tolerance of plants. However, it still remains unknown whether the application of [...] Read more.

Soil salinity is one of the major factors that affect plant growth and decrease agricultural productivity worldwide. Chitosan (CTS) has been shown to promote plant growth and increase the abiotic stress tolerance of plants. However, it still remains unknown whether the application of exogenous CTS can mitigate the deleterious effects of salt stress on lettuce plants. Therefore, the current study investigated the effect of foliar application of exogenous CTS to lettuce plants grown under 100 mM NaCl saline conditions. The results showed that exogenous CTS increased the lettuce total leaf area, shoot fresh weight, and shoot and root dry weight, increased leaf chlorophyll a, proline, and soluble sugar contents, enhanced peroxidase and catalase activities, and alleviated membrane lipid peroxidation, in comparison with untreated plants, in response to salt stress. Furthermore, the application of exogenous CTS increased the accumulation of K⁺ in lettuce but showed no significant effect on the K⁺/Na⁺ ratio, as compared with that of plants treated with NaCl alone. These results suggested that exogenous CTS might mitigate the adverse effects of salt stress on plant growth and biomass by modulating the intracellular ion concentration, controlling osmotic adjustment, and increasing antioxidant enzymatic activity in lettuce leaves. Full article

(This article belongs to the Special Issue Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants)

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21 pages, 11256 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Cold Stress in Citrus: A Molecular, Physiological and Biochemical Perspective

by Amparo Primo-Capella, Mary-Rus Martínez-Cuenca and María Ángeles Forner-Giner

Horticulturae 2021, 7(10), 340; https://doi.org/10.3390/horticulturae7100340 - 24 Sep 2021

Cited by 14 | Viewed by 3851

Abstract

Due to climate change, we are forced to face new abiotic stress challenges like cold and heat waves that currently result from global warming. Losses due to frost and low temperatures force us to better understand the physiological, hormonal, and molecular mechanisms of [...] Read more.

Due to climate change, we are forced to face new abiotic stress challenges like cold and heat waves that currently result from global warming. Losses due to frost and low temperatures force us to better understand the physiological, hormonal, and molecular mechanisms of response to such stress to face losses, especially in tropical and subtropical crops like citrus fruit, which are well adapted to certain weather conditions. Many of the responses to cold stress that are found are also conserved in citrus. Hence, this review also intends to show the latest work on citrus. In addition to basic research, there is a great need to employ and cultivate new citrus rootstocks to better adapt to environmental conditions. Full article

(This article belongs to the Special Issue Rootstocks: History, Physiology, Management and Breeding)

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