Fruit Quality Research Articles

Effect of bioactive compounds on enzymatic regulation and shelf life of mango during post-harvest

The effects of melatonin, salicylic acid (SA) and brassinosteroids on the post-harvest quality and shelf life of two mango varieties, Alphonso and Sindhura, were investigated with respect to physiological, biochemical and enzymatic changes. The study assessed physiological loss in weight (PLW), Total Soluble Solids (TSS), titratable acidity, sugars, total phenolics, carotenoids, ripening related enzymes (pectin methylesterase, polygalacturonase, amylase and cellulase) and antioxidant enzymes (peroxidase, catalase and superoxide dismutase). According to the results, the shelf life of mango was considerably increased by 200 µM melatonin, 2.0 mM salicylic acid and 25 ppm brassinosteroids, which also decreased PLW to 9.81 %, 10.12 % and 9.79 % in Alphonso and 9.48 %, 9.51 % and 9.92 % in Sindhura. These treatments maintained a balance between TSS, sugars and acidity, while preserving higher concentration of total phenolics and carotenoids. Treated fruits exhibited lower ripening enzyme activity, particularly polygalacturonase, which declined by 16.7 %, 11.2 % and 17.0 % in Alphonso and 11.5 %, 10.9 % and 11.2 % in Sindhura with 200 µM melatonin, 2.0 mM salicylic acid and 25 ppm brassinosteroids treatments respectively. Similarly, pectin methyl esterase (PME) was reduced by 12.2 %, 11.6 % and 10.5 % in Alphonso and 12.1 %, 10.3 % and 12.1 % in Sindhura corresponding to these treatments, delaying cell wall degradation and maintaining fruit firmness. Additionally, antioxidant enzymes were upregulated, mitigating oxidative stress by reducing reactive oxygen species (ROS) and preserving fruit quality. These treatments were effective in delaying ripening, enhancing stress resistance and extending the marketability of mangoes during storage. This study highlights the potential of melatonin, salicylic acid and brassinosteroids as eco-friendly alternatives to synthetic chemicals for improving post-harvest mango management.

Phytic Acid Delays the Senescence of Rosa roxburghii Fruit by Regulating Antioxidant Capacity and the Ascorbate–Glutathione Cycle

Rosa roxburghii fruit has a short postharvest shelf life, with rapid declines in quality and antioxidant capacity. This research assessed how phytic acid affects the antioxidant capacity and quality of R. roxburghii fruit while in the postharvest storage period and reveals its potential mechanism of action. The findings suggested that phytic acid treatment inhibits the production of malondialdehyde (MDA) and enhances the activities and expressions of glutathione peroxidase (GPX), peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) while decreasing the generation of superoxide anions (O2•−) and hydrogen peroxide (H2O2). Phytic acid treatment activates the ascorbate–glutathione (AsA-GSH) cycle and enhances the activity and expression of key enzymes in the cycle: ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR). It also increases the levels of non-enzymatic antioxidants, such as ascorbic acid (AsA) and glutathione (GSH), while reducing the production of dehydroascorbic acid (DHA) and oxidized glutathione (GSSG). Moreover, phytic acid treatment enhances the ratios of AsA/DHA and GSH/GSSG, maintaining the reduced state of the fruit. In summary, phytic acid improves antioxidant defense system and activates the AsA-GSH cycle, alleviating oxidative damage and ensuring R. roxburghii fruit quality after harvest.

Trans-2-hexenal reduces postharvest mango stem-end rot by oxidative damage to Neofusicoccum parvum cell membranes.

Neofusicoccum parvum is one of the most hazardous pathogens causing mango fruit decay. The present study utilized trans-2-hexenal (TH), a typical antifungal component of plant essential oils (EOs), to control N. parvum both in vivo and in vitro, and attempted to explore the mechanisms involved. The findings showed that at concentrations greater than 0.4 µL/mL, TH exhibited exceptional antifungal activity against N. parvum in vitro. TH application led to the disruption of the structural integrity of both cell walls and cell membranes, with a particular impact on the latter, as evidenced by the dramatically increased propidium iodide level, as well as reduced total lipids and ergosterol content. Further DCFH-DA staining experiments showed that TH induced mycelial reactive oxygen species (ROS) accumulation, which exacerbated cell membrane lipid peroxidation. For easier application of TH, we fabricated aerogel-loaded TH (ALTH) materials, which demonstrated excellent antifungal activity in vitro. Infestation studies on fruits demonstrated that ALTH mitigated mango stem-end rot in a dose-dependent fashion, with a concentration of 40 µL/L showing efficacy comparable to the conventional fungicide prochloraz, while maintaining fruit quality. In light of these results, TH works by inducing ROS buildup and oxidative damage to the cell membrane of N. parvum, and is a particularly promising preservative for preventing postharvest infections in mangoes.

Effect of Foliar Application of Calcium and Salicylic Acid on Fruit Quality and Antioxidant Capacity of Sweet Pepper (Capsicum annuum L.) in Hydroponic Cultivation

The aim of this study was to investigate the effect of foliar application of calcium and salicylic acid on improving the physicochemical quality, sensory quality and antioxidant potential of pepper fruits grown hydroponically in mineral wool substrate. Two sweet pepper varieties with red fruit type were used: block Aifos and elongated Palermo. Fruit quality was tested from four plant treatment combinations: (1) water (control), (2) calcium nitrate 0.7% (Ca), (3) salicylic acid 0.03% (SA), (4) calcium nitrate and salicylic acid combined (Ca+SA). Fruits of both varieties showed high concentrations of health-promoting constituents, including potassium, phosphorus, vitamin C (over 47 mg 100 g⁻1 of FW (fresh weight)), and carotenoids, with capsanthin being the most abundant (more than 1226 μg 100 g⁻1 of FW). The results of the sensory evaluation demonstrated that the attributes tested scores above 7 out of 10, indicating a high sensory quality. The antioxidant activity of pepper fruits was determined by three different methods: DPPH (method for measuring the antioxidant activity of DPPH), ABTS (method for measuring the antioxidant activity of ABTS) and TPC (total polyphenol content) and averaged more than 86%, 78% RSC (radical scavenging capacity) and almost 54 mg CE (catechin) 100 g⁻1 of FW for both cultivars, respectively. Fruit quality results were analysed using PCA (principal component analysis). The first two principal components (PC1 and PC2) explained almost 54% of the variation, highlighting the strong correlations of PC1 with dry matter content, soluble sugars, potassium, acidity and sensory characteristics of pepper fruit such as skin hardness and flesh firmness. The application of SA to peppers resulted in an increase in the carotenoid content of the fruit. Furthermore, a notable positive correlation was detected between total sugars and the sugar/acid ratio when Ca+SA was combined in both cultivars. Palermo fruit showed better quality parameters and higher antioxidant activity, making this sweet pepper variety particularly valuable in a health-promoting context.

High-Quality Citrus: Advances in Mastication Trait Research and Applications

The mastication trait of citrus fruit is a key determinant of consumer preference and market value, which is influenced by a combination of genetic, environmental, and postharvest factors. This review focuses on analyzing these factors and their impacts on citrus fruit quality, with a particular emphasis on masticatory properties. The biochemical and molecular mechanisms underlying mastication traits are examined, focusing on cell wall metabolism (pectin, cellulose, lignin), cytoplasmic and intercellular matrix changes, and molecular regulation. Strategies for improving citrus quality and mastication traits are discussed, emphasizing varietal improvement through gene editing technologies, optimized cultivation practices, and advanced postharvest handling techniques. Despite significant progress, challenges remain in elucidating the complex genetic and environmental interactions governing these traits and developing sustainable management practices. Future research should integrate multiomics approaches, gene–environment interaction studies, and precision agriculture to address these challenges. This review provides a comprehensive synthesis of the current knowledge and prospective directions, aiming to guide the development of high-quality citrus varieties with enhanced mastication traits.

Acceleration of Breaking Buds Dormancy on Apricot Trees by Using Alternatives of Hydrogen Cyanamide (Dormex) and Assessment of Resulting Fruits Quality

The purpose of this research was to determine the effectiveness of alternatives of dormex on apricot budbreak and their effect on apricot fruit quality. Our study was carried out on five-years old “Canino” apricot at Badr district, El Behira Governorate, Egypt, during the two seasons 2022 and 2023, respectively. Twenty-four uniform apricot trees were selected and sprayed to the runoff once on 20 and 25 January during 2022 and 2023, respectively, by following treatments: control, mineral oil at 2%, low pyrite urea at 2%, ammonium nitrate at 1.5%, potassium nitrate at 2%, mineral oil combined with low pyrite urea at the same concentration of 2%, mineral oil at 2 % combined with ammonium nitrate at 1.5 %, mineral oil combined with potassium nitrate at the same concentration of 2%. For each of the treatments that were used, 0.05% (v/v) of the non-ionic surfactant tween 80 was applied. In both seasons, the use alternatives dormex chemicals resulted in better budbreak than control trees especially the formulation of mineral oil at (2%) plus potassium nitrate (2%).

Tea Tree Oil Delays Kiwifruit Ripening Through Regulating Energy Metabolism

ABSTRACTKiwifruit is easy to ripen and soften after harvest. Tea tree oil (TTO) has important application value in postharvest fruit preservation. However, the effect of TTO on kiwifruit fruit ripening, quality maintenance and energy metabolism, has not been studied. In this research, we found that TTO could delay ‘Xuxiang’ kiwifruit ripening, and keep good quality even after 18 days of storage. In three different concentrations of TTO treatments, 2.0 mL L−1 TTO has the best preservation effect on kiwifruit. TTO slowed down the softening and degreening, reduced the respiration intensity and delayed the peak of respiration. Moreover, TTO also delayed the decrease of total sugar, titratable acid (TA) and vitamin C (Vc). The fruit treated with TTO kept higher levels of ATP, ADP and energy charge (EC), and higher activities of succinate dehydrogenase (SDH), cytochrome C oxidase (CCO) and ATPase. Correlation analysis results showed that kiwifruit ripening was closely related to nutritional quality and energy metabolism. To summarize, TTO could delay kiwifruit ripening and keep fruit quality by maintaining higher energy level and activities of energy metabolism‐related enzymes during the late storage. This study will provide theoretical and technical support for kiwifruit preservation.

ВЛИЯНИЕ НЕКОРНЕВЫХ ОБРАБОТОК НА УПРАВЛЕНИЕ СКОРОСТЬЮ СОЗРЕВАНИЯ ПЛОДОВ ЯБЛОНИ

The purpose of research is to study the actions of growth regulators based on 1-methylcyclopropene (Harvista) to give an attractive appearance, improve the taste of apple fruits and control the maturation rate. The results of the use of non-root treatments with a growth regulator based on 1-methylcyclopropene (Harvista) on the fruits of the Red Delicious apple variety grown in the Krasnodar Region, which allow controlling the intensity of ethylene release and increasing the period of fruit maturation, helping to extend the harvest time, are presented. Processing fruits was carried out by Harvista once 10 days before the removal of fruits. A decrease in the concentration of ethylene in fruits contributed to less shedding of apples and, accordingly, an increase in yield. The extension of the harvest period contributed to an increase in the weight of the fruits of the Red Delicious variety up to 337.5 g (by 8–10 %). A decrease in fruit shedding when using Harvista and an increase in the weight of apples contributed to an average of up to 15.3 kg/tree, or 54.7 t/ha, in the control – 11.8 kg/tree, or 42.2 t/ha . The use of this preparation made it possible to stimulate the development of the integumentary color of the fruit, and by the beginning of the harvest, the apples had a more attractive presentation due to an increase in the content of anthocyanins in the skin of the fruit. The study of the effect of non-root treatments with a growth regulator (Harvista) showed an increase in the resistance of fruits to damage when exposed to a stressor, as well as a positive effect on the qualitative composition of fruits (pulp hardness, dry matter content, vitamins, minerals), which made it possible to increase the shelf life of apples. The result of using this growth regulator is better fruit quality and higher yields.

Mechanism of Exogenous Silicon in Enhancing Cold Stress Tolerance in Solanum lycopersicum L. Seedlings: Insights from Resistance and Quality Indicators

Environmental stress, notably the exposure to low temperatures during the early developmental stages of seedlings, has been identified as a critical determinant impacting the yield and quality of tomato crops cultivated in greenhouses. Silicon (Si), recognized as a beneficial element, is posited to mitigate the adverse effects of such stress on plant physiology. This study explores whether exogenous Si fertilizer can effectively alleviate the stress of low temperature and cold damage on tomato plant growth, fruit yield, and quality. Tomato plants were placed under low temperature conditions (6 °C at night, daily average temperature 15 °C), with normal temperature conditions as the control (below 16 °C at night, daily average temperature 28 °C), and two different concentrations of nano Si and ionic Si (50 mg·L−1 and 200 mg·L−1) were sprayed on the leaves, with an equivalent amount of deionized water as the control, for a total of 10 treatments. Relevant indexes were measured to investigate the effects of exogenous Si on tomato resistance, yield, and quality under low-temperature stress. The results show that compared with the control treatment, the plant height, stem diameter, and fresh weight of above-ground and underground parts of tomato seedlings decreased significantly by 46.52%, 42.53%, 28.81%, and 28.97%, respectively, after 15 days of low-temperature stress (p < 0.05), and in order to resist low temperature, the activity of antioxidant enzymes and the content of osmotic adjustment substances were up-regulated in seedlings. Ultimately, low-temperature stress inhibited the morphological growth, nutritional quality, and yield of fruits. Both concentrations of Si application can promote the growth and biomass accumulation of tomato plants under low temperature conditions. Moreover, it significantly ameliorated the osmotic adjustment and antioxidant capacity of the plants, thereby alleviating the low-temperature stress. Under low-temperature stress, 50 mg L−1 ionic Si was the most effective for increasing tomato yield per plant, which was significantly increased by 22.44% compared with the control treatment (p < 0.05). Consequently, the study advocates for the application of 50 mg·L−1 ionic Si fertilizer as a strategy to mitigate the impact of low-temperature stress on tomato plants. Furthermore, the use of nano Si fertilizer has been demonstrated to exert a significant influence on enhancing both the yield and quality of tomatoes, with a 50 mg·L−1 concentration of nano Si fertilizer leading to a notable increase in yield by 20.15% under normal temperature conditions (p < 0.05). These findings are intended to furnish a theoretical foundation and practical direction for advancing research aimed at combating the detrimental effects of low-temperature stress in the context of protected vegetable cultivation.

Effects of different rootstocks on the essential oil composition in the peel and leaf of rio red grapefruit

TThe use of rootstocks in citrus production is an increasingly common in practice. The selection of the appropriate rootstock is important in many aspects such as the adaptation of the variety to environmental conditions, growth, fruit set, flowering, fruit yield and fruit quality. In the present study, essential oil yields and components determined in the peels and leaves of Rio Red grapefruit grafted onto 7 different citrus rootstocks were compared. While essential oil yields from the peels of rootstocks were identified ranged between 0.5% and 1.5%, measurements could not be made due to trace amounts in the leaves. The essential oil composition was characterized using GC-MS, with limonene being the main identified compound in all the peels with 93.39 and 95.44% in Carrizo citrange and Volkameriana, respectively. However, in the leaves of rootstocks, besides limonene, major compounds were changed. In the leaves of Brazilian sour orange, β-sinensal was detected at significantly higher ratio (33.53%), sabinene was found at high ratios in Smooth Flat Seville sour orange (27.62%).

Assessment of<i> in vitro alpha</i>-glucosidase inhibitory activity, phenolics, flavonoidsand antioxidant potential of jamun (<i>Syzygium cumini)</i> seeds

Jamun (Syzygium cumini Linn. Syn. Eugenia jambolana) genotypes collected from different parts of the country were evaluated for in vitro alpha-glucosidase inhibitory activity, polyphenolic content and antioxidant potential along with fruit characters. Results indicated significant variation among genotypes for fruit characters, phenolics, flavonoids, antioxidant potential, and alpha-glucosidase inhibitory potential. Total phenolics and flavonoids in seeds varied between 15.5 mg to 98.7 mg GAE/g and 0.79 mg to 9.03 mg CE/g seeds, respectively. The seeds with a high content of polyphenolic compounds required a very less amount of sample to inhibit alpha-glucosidase enzyme. The genotype Selection 45 recorded the highest alpha-glucosidase inhibitory activity, and required only 50.3 µg of sample to inhibit 50 % of the enzyme activity. Both phenolics and flavonoids content positively correlated with antioxidant potential and negatively correlated with enzyme inhibitory potential. From cluster analysis, the genotypes AJG-85, Kaithanal, Selection-45, Collection-2, and Konkan Bahdoli were identified as superior genotypes having a considerable amount of seeds with alpha glucosidase inhibitory compounds. These genotypes/collections may be effectively utilized for further studies to isolate and characterize the bioactive constituents with alpha-glucosidase inhibitory potential.

Effect of insect pollinators on quantitative yield parameters of okra (Abelmoschus esculentus) in mid-Himalayan region

Okra [Abelmoschus esculentus (L.) Moench] is an often cross-pollinated crop with up to 19–42% of cross pollination assisted by insects and planned pollination may improve the economic fruit yield and biological parameters. The present study was carried out during rainy (kharif) seasons of 2021 and 2022 at Research Farm of ICAR-Vivekananda Parvatiya Krishi Anusandhan Sansthan, Hawalbagh, Almora, Uttarakhand to assess the pollinator diversity and possible results (both biological and economical) of planned bee pollination. The study on floral visitors of okra recorded 28 insect spp. belonging to four insect orders, among which five spp., viz. Apis cerana indica (Fabricius) 1798, Apis mellifera (Linnaeus) 1758, Bombus haemorrhoidalis (Smith) 1852, Lithurgus atratus (Smith) 1853 and Xylocopa latipes (Drury) 1773 were predominant. The foraging activity and pollination behaviour showed that two non-Apis bee species (X. latipes and B. haemorrhoidalis) were swift flyers and visited more numbers of flowers per unit time. It was noticed that, peak period of pollinator’s visitation was between 9.00–11.00 h accounting to 113.76±7.65 insects/m2/10 min, during which stigma receptivity and pollen germination were at its peak. Assessment of yield related parameters of insect pollinated flowers showed superior quality fruits with better capsule length (17.4–20.9 cm), capsule girth (6.56–7.84 cm), seeds/capsule (51.4–60.6), test weight of 100-seeds (7.05–8.38 g) and even the seed yield (1.86–3.04 tonnes/hectare) than closed control and hand pollination (emasculated and cross pollinated). In conclusion, ecological engineering of okra fields enhances the pollination rate and ultimately the yield and seed quality.

Identification and characterization of thorny and high temperature tolerant brinjal (Solanum melongena) genotype for hot arid environment

Brinjal (Solanum melongena L.) is one of the most common vegetable which is generally cultivated as rainy (kharif) season crop to get the fruits during autumn-winter season. However, the summer season crop has more potential than the kharif season as the fruits harvested during summer gets premium price in the market. But, getting high quality fruit yield during summer due to high temperature stress (>45°C) is a challenge particularly in hot arid agro-climate as the day and night temperature above 35°C reduces the pollen viability, fruit set, number of fruits/plant and colour retention to a great extent. The present study was carried out during 2020 and 2021 at ICAR-Central Institute of Arid Horticulture, Bikaner, Rajasthan to develop varieties with better quality fruit yield under high temperature conditions. The experiments were conducted in split plot design (SPD) considering environments as main plots and replicates within environment as subplots with three replications. As a result, CIAH-22 has been identified and characterized as a trait specific high temperature tolerant (up to 45°C) thorny brinjal genotype suitable for hot arid region. Fruit weight at marketable stage varied from 144.56–155.84 g that indicates bigger sized fruits with thorns on calyx which are preferred most by the local growers and consumers of this region. It has the yield potential of 2.18–3.72 kg fruits/plant and 447.78–471.74 q/ha. The identified genotype CIAH-22 was able to set fruits at temperature as high as 45°C which was also evidenced by its pollen viability i.e. 83.71%. High pollen viability significantly enhanced fruit set, fruit weight and number of fruits per plant and thereby yield under high temperature stress. Thus, this identified genotype can be a potential source for brinjal improvement for high temperature tolerance and regional preference of big-sized thorny fruits with attractive colour retention.

Investigation of Effects of Cushioning Packaging on the Physiological and Quality Changes in Chinese Olive Fruits During Cold Chain Transportation.

To gain a deeper understanding of the mechanisms by which cushioning packaging preserves the quality of Chinese olive fruits during cold chain transportation and extends their shelf life, this study simulated cold chain conditions and investigated the effects of cushioning packaging on the physiology, antioxidant capacity, and secondary metabolites of fruits during a 20-day shelf life. The results indicated that the decay rate in cushioning-packaging-treated fruit was 75% lower than that in the unbuffered packaging fruit at day 20 of shelf life. Simultaneously, cushioning packaging treatment mitigated the damage severity of the cell membrane structure and kept the cell membrane permeability at a low level, which was 15.34% lower than that in the unbuffered packaging fruit at day 20 of shelf life. Additionally, cushioning packaging effectively restrained the increases in malondialdehyde (MDA) content and alleviated the decline in chlorophyll and total flavonoid contents. It kept a balance among reactive oxygen species (ROS), antioxidant levels, and antioxidant enzyme activities, thereby reducing mechanical-damage-induced decay rates in Chinese olive fruits during the shelf life. Furthermore, metabolome analysis of Chinese olives during the shelf life was performed comparing those without buffered packaging to those with buffered packaging. The metabolome analysis found that the flavonoid biosynthetic pathway exhibited a higher accumulation of chrysin, neohesperidin, naringenin chalcone, sakuranetin, quercetin, catechin, and naringenin metabolites in cushion-packaging treatment compared to those without cushioning treatment. Furthermore, within the phenylalanine metabolic pathway, the accumulation of phenylalanine, p-coumaraldehyde, p-coumaric acid, coniferin and caffeoyl quinic acid metabolites was significantly higher in buffered-packaging groups compared to those without buffering. Together, these findings suggest that cushioning packaging can effectively sustain the integrity of cell membranes and enhance the shelf-life quality of Chinese olive fruits by regulating the balance of ROS and mitigating oxidative stress during cold chain transportation.

Elevated CO2 in dynamic controlled atmosphere storage: Impact on anaerobic metabolism and overall quality of 'Maxi Gala' apples.

The present study investigated the effects of high CO2 partial pressures (pCO2) in dynamic controlled atmosphere monitored by respiratory quotient (DCA-RQ 1.3) on the anaerobic metabolism compounds, physiological disorders and overall quality of 'Maxi Gala' apples after 9 months of storage (2.0 °C), plus 7 days of shelf life (20 °C). Two experiments were conducted over 2 years. In the first year, 'Maxi Gala' apples were stored under controlled atmosphere (CA - 1.2 kPa O2 + 2.0 kPa CO2), CA + 1-methylcyclopropene (1-MCP), DCA by chlorophyll fluorescence (DCA-CF + 1.2 kPa CO2) and DCA-RQ 1.3 with different pCO2 (0.4, 1.2, and 1.6). The same treatments were evaluated in the second year, with addition of DCA-RQ 1.3 + 2.0 kPa CO2. 'Maxi Gala' apple stored under DCA-RQ 1.3 + 0.4 kPa CO2 and DCA-CF maintained healthy fruit amount similar to DCA-RQ 1.3 + 1.2 and 1.6 kPa CO2, but with lower flesh firmness. DCA-RQ 1.3 with higher pCO2 (1.6 or 2.0) increases the production of ethyl acetate, but did not impact physiological disorders compared to DCA-CF. CA + 1-MCP maintained high flesh firmness, but reduced healthy fruit amount. The present study has demonstrated that DCA-RQ 1.3 with 1.6 or 2.0 pCO2 can be adopted for 'Maxi Gala' apples storage, resulting in similar or better fruit quality than DCA-RQ 1.3 + 1.2 kPa CO2. Additionally, the adoption of high pCO2 in the DCA-RQ storage system can result in cost reductions related to CO2 adsorption. © 2024 Society of Chemical Industry.

Cu-Doped MnO2 Catalysts for Effective Fruit Preservation via Ozone Synergistic Catalytic Oxidation.

Developing and implementing technologies that can significantly reduce food loss during storage and transport are of paramount importance. Ozone synergistic catalytic oxidation (OSCO) technology has been developed, which sterilizes bacteria and viruses on the surface of food and degrades ethylene released during fruit storage through the active oxygen produced by the catalytic decomposition of ozone. Herein, we report the hydrothermal synthesis of MnO2 with distinct phase compositions and nanostructures through simply varying the reaction temperatures. Optimized copper-doped α-MnO2 nanorods exhibited remarkable efficacy in activating ozone at a concentration of 40 ppb, and this activation resulted in the complete eradication of indicator bacteria on food surfaces within a 24 h period. Moreover, these nanorods demonstrated high effectiveness in decomposing more than 80% of the ethylene molecules emitted by apples and bananas during the preservation period. The high concentration of surface oxygen vacancies is believed to contribute to the enhanced catalytic activity of the Cu-doped α-MnO2 catalyst in the OSCO procedure by reducing ethylene production and maintaining the fruit quality during the preservation period.

Effects of Cyclic Aeration Subsurface Drip Irrigation on Greenhouse Tomato Quality and Water and Fertilizer Use Efficiency.

Tomato (Jinglu 6335) was selected for assessing the impact of varying fertilizer (F:N-P2O5-K2O) and aeration rates on crop quality, as well as water and fertilizer utilization efficiency during the cyclic aeration subsurface drip irrigation process. Four aeration treatments (O1, O2, O3, and S, representing aeration ratios of 16.25%, 14.58%, 11.79%, and non-aerated treatment, respectively) and three fertilizer applications (F1: 240-120-150 kg/hm2, F2: 180-90-112.5 kg/hm2, F3: 120-60-75 kg/hm2) were compared in a total of 12 treatments in this study. This study revealed that cyclic aerated drip irrigation improved the fruit quality. The aerated treatment resulted in increased accumulation of nitrogen, phosphorus, and potassium, with the level of aeration positively correlating with the increase in nutrient accumulation, reaching the highest values in the high aeration irrigation treatment. The highest nitrogen, phosphorus, potassium, and water use efficiency occurred under the medium fertilizer with high aeration treatment. The maximum partial productivity of the fertilizer occurred under the low fertilizer with high aeration treatment, while the minimum occurred in the high fertilizer with non-aerated treatment. Taking all factors into consideration, the high-aeration and medium-fertilizer treatment was the most effective combination for greenhouse tomatoes under the conditions in this experiment.

Mechanism of induced soluble sugar accumulation and organic acid reduction in plum fruits by application of melatonin

Melatonin (MT) can improve plant resistance and fruit quality. The mechanism by which MT affects soluble sugar and organic acids accumulation in drupe fruits is not clear. In this study, 100 µmol/L MT was sprayed on the leaves of plum trees at the second stage of rapid fruit expansion (90 and 97 d after flowering), and the effects of MT on plum fruit quality and its effects on the soluble sugar-organic acid metabolism were investigated. At 28 d after MT treatment (at maturity), the longitudinal diameter, fruit weight, and vitamin C content of plum fruits were increased by 5.05%, 12.93%, and 56.09%, respectively, compared to the control. MT caused significant increase in the total soluble solids content and decreased the titratable acid content. MT increased the contents of total soluble sugar, sucrose, sorbitol, and citric acid after 21 and 28 days of treatment, while decreasing the contents of fructose, malic acid, quinic acid, and tartaric acid after 28 days of treatment. Additionally, MT increased the activities of sucrose synthase (catabolism direction), sucrose phosphate synthase, glucokinase, fructokinase, sorbitol oxidase, and NADP+-malic enzyme, and decreased the activities of soluble acid converting enzyme, cell wall insoluble converting enzyme, NAD+-sorbitol dehydrogenase, and NAD+-malic dehydrogenase after 21 or 28 days of treatment. Moreover, the differentially expressed genes (DEGs) after 21 and 28 days of treatment were accelerated starch and sucrose metabolism, galactose metabolism, fructose and mannose metabolism, as well as glycolysis, gluconeogenesis, and pentose phosphate metabolism pathways. In conclusion, exogenous MT increases soluble sugar content and decreases organic acid content in plum fruits by regulating various soluble sugar-organic acid metabolic pathways, thereby improving the fruit quality.

Characterization of a tomato chlh mis-sense mutant reveals a new function of ChlH in fruit ripening.

Tomato fruit ripening is a complex developmental process that is important for fruit quality and shelf life. Many factors, including ethylene and several key transcription factors, have been shown to play important roles in the regulation of tomato fruit ripening. However, our understanding of the regulation of tomato fruit ripening is still limited. Here, we describe mut26, an EMS-induced tomato (Solanum lycopersicum) mutant that exhibits chlorophyll-deficient phenotypes in various organs, including fruits. Genetic mapping and functional analyses revealed that a single-nucleotide substitution and a corresponding Pro398->Ser mis-sense mutation in SlChlH (GENOMES UNCOUPLED 5, GUN5), which encodes the H subunit of magnesium chelatase, are responsible for the defects in the mut26 strain. Transcript analyses towards the expression of many SlPhANGs revealed that mut26 is defective in plastid retrograde signalling during tomato fruit ripening initiation, namely the transition from mature green to breaker stage. mut26 exhibits delayed progression of fruit ripening characterized by reduced fruit ethylene emission, increased fruit firmness, reduced carotenoid content and delayed plastid conversion from chloroplast to chromoplast. Given that fruit ripening requires signalling from plastids to nucleus, these data support the hypothesis that GUN5-mediated plastid retrograde signalling promotes tomato fruit ripening. We further showed that the delayed fruit ripening of mut26 is not likely caused by reduced chlorophyll content. Taken together, we identified a new function of SlChlH in the promotion of tomato fruit ripening and ethylene biosynthesis, suggesting that GUN5-mediated plastid retrograde signalling plays a promotive role in tomato fruit ripening.

Exogenous phenylalanine application effects on phytochemicals, antioxidant activity, HPLC profiling, and PAL and CHS genes expression in table grapes (Vitis vinifera cv. ‘Qzl Ouzum’)

BackgroundGrape (Vitis vinifera L.) is one of the most important fruit products globally and has a high nutritional value with potent antioxidant and anti-cancer activities. In current years, phenylalanine application has been particularly noticed for enhancing the nutritional quality of horticultural crops. With the aim of quality improvement, the effects of foliar application of phenylalanine at 5 concentrations (0, 100, 500, 1000, and 2000 μM) on Vitis vinifera cv. ‘Qzl Ouzum’ berry compositions were studied. The studied parameters included antioxidant activity, phenolics, flavonoids, anthocyanin, catalase and phenylalanine ammonia-lyase enzyme activity, and phenolic compounds content based on HPLC analyses (myricetin, quercetin, kaempferol, syringetin, catechin, gallic acid, caffeic acid, p-coumaric acid, resveratrol).ResultsPhenylalanine at 1000 μM increased total phenols, flavonoids, anthocyanins, and PAL enzyme activity. In addition, HPLC analysis revealed a significant accumulation of individual phenolic compounds by phenylalanine treatment. The highest values were recorded in the treatments with 100 and 500 μM phenylalanine for most of the phenolic components. Real-time quantitative RT-PCR results showed that the expression of PAL and CHS genes was induced by phenylalanine. The highest PAL and CHS gene expression was observed at 500 μM and then at 1000 μM phenylalanine treatment.ConclusionsWith the use of phenylalanine, the activity of the PAL and CHS enzyme and PAL and CHS gene expression were significantly increased and led to a greater accumulation of phenolic compounds and antioxidant activiety. This study suggests that the use of phenylalanine as a main precursor for the synthesis of phenolic compounds, can improve the phenolic composition of grapes and could be a practical approach to advance fruit quality in the production of grape cv. ‘Qzl Ouzum’.