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Little is known about the relative impact of lighting duration and light intensity on lettuce production, as well as whether daily light integrals (DLIs) play a significant role during different plant growth stages. Four DLIs were tested: 8.64, 11.52, 12.96, and 17.28 mol m−2 day−1 as supplemental lighting, which were obtained from a combination of supplemental light intensities at 200 and 300 µmol m−2 day−1 for 12 and 16 h. Sunlight was used as control. A direct correlation was observed between DLIs and yield, total fresh weight, and total dry weight. Under supplemental lighting, relative growth rate (RGR) increased due to an increase in net assimilation rate (NAR) rather than in leaf area ratio (LAR). Plants in the seedling stage were more sensitive to an elevation in DLI than in the head stage. This was confirmed by a greater increase in NAR compared to their corresponding control under the same DLI. Increasing DLI also improved lettuce quality via reducing nitrate and increasing protein content. Higher DLIs (12.96 and 17.28 mol m−2 day−1) led to a decrease in maximum quantum yield of photosystem II and an increase in performance index. In conclusion, manipulating RGR through NAR adjustments proved to be more effective than changes in LAR, and adjusting supplemental DLI at each stage was necessary to achieve a larger NAR and, consequently, a larger RGR. Core Ideas: A direct correlation was observed between daily light integrals and yield.Relative growth rate increased due to increase in net assimilation rate rather than in leaf area ratio.Higher daily light integral resulted in a decrease in maximum quantum yield of photosystem II and an increase in performance index.Increasing the daily light integral led to an increase in lettuce quality. [ABSTRACT FROM AUTHOR]

Grape is a staple crop in many parts of Iran which has shown moderate sensitivity to salinity stress. Water and soil salinity is one of the major environmental stresses that strongly affect the production of agricultural products, including grapes. To overcome the harmful effects of salinity, different methods and materials are used, one of which is the use of nitric oxide. In order to explore the impact of nitric oxide on the mitigation of the negative effects of salinity stress on four grape cultivars and rootstocks ('Bidaneh Sefid' (Sultana) and 'Yaghouti' cultivars, and 140Ru and 1103 P rootstocks), a pot experiment was performed in a factorial based on a randomized complete block design with three replications. Plants were subjected to three sodium chloride (NaCl) levels of 0 (control), 25, and 50 mM and three levels of sodium nitroprusside (SNP) of 0 (control), 0.5, and 1 mM. Results indicated that increasing SNP concentration caused an increase in growth indices such as leaf area, shoot and root length, fresh and dry weights of leaves, shoots, and roots, and leaf relative water content (RWC). Furthermore, salinity decreased the concentrations of potassium (K+), calcium (Ca2+), magnesium (Mg2+), and iron (Fe2+) in leaves, while increased the amount of sodium (Na+) and chlorine (Clˉ) as well as the electrolyte leakage (EL). In addition, SNP at 0.5 and 1 mM could increase the growth efficiency and RWC as well as the elements such as K+ and Mg2+ while decreased the absorption of Na+ and Clˉ as well as the EL in plants under salinity. According to the obtained results, SNP at both concentrations (0.5 and 1 mM) had a pronounced effect on reducing the negative effect of salinity in the evaluated grape rootstocks and cultivars. In general, the positive effects of SNP on 'Yaghouti' and 'Bidaneh Sefid' cultivars were higher than those on 140Ru and 1103 P rootstocks. [ABSTRACT FROM AUTHOR]

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Lettuce is one of the most important leafy vegetable crops. Despite lettuce being mostly grown in open fields, its greenhouse production is widely increasing. Lettuce growth comprises two distinct stages known as the seedling and head stages. The effect of supplemental lighting (SL) on lettuce growth was well studied, but the lighting requirement during the early stage of its growth and head development remained unknown. For this purpose, we evaluated nutritional qualities and growth in lettuce in response to SL in separate seedling and head development stages. The experiment involved SL with different daily light integral (DLI) provided by light-emitting diodes (LEDs). Light treatments included supplemental DLI of 8.64, 11.52, 12.96, and 17.28 mol m-2 d-1. The results revealed that the lighting period was more effective on lettuce biomass increase than the light intensity. Although the SL increased the photosynthetic pigment content of lettuce, its impacts on the two growth stages were not the same. In a way, the chlorophyll a, total chlorophyll, and carotenoid contents decreased under the SL conditions (DLI of 17.28 mol m-2 d-1 and light intensity of 300 µmol m-2 s-1 for 16 h). Increasing DLI caused a significant increase in the nutritional quality of lettuce, but antioxidant accumulation did not follow a similar trend in seedlings and mature plants. These findings confirmed that SL improves lettuce growth and quality, but optimal lighting requirements may vary depending on the growth stage. [ABSTRACT FROM AUTHOR]

The effect of external application of ornithine amino acid on the morphological characteristics, mineral elements content and antioxidant activity of pistachio cv. Ahmad Aghaei was studied as a two-year experiment. Foliar application of ornithine in four concentrations (0, 2.5, 5 and 7.5 mM) at four stages, including bud swelling, leaf area reaching 5%, leaf area reaching 75%, and concurrent with the initial start of kernels filling, was done. The results showed that the highest fresh and dry weight of the fruit, current year shoot length, leaf area, split nuts percentage and the lowest blank nuts percentage was obtained at the level of 7.5 mM ornithine. Foliar application of ornithine was able to affect the macro and micro elements content in pistachio leaves and fruits, such that the highest amount of nitrogen, phosphorus, calcium, iron and zinc elements in pistachio leaves and fruits was obtained at the level of 7.5 mM of ornithine. The ornithine also significantly improved the antioxidant capacity and activity of treated trees, and the highest activity of antioxidant enzymes comprises ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD) enzymes was obtained in the samples treated with 7.5 mM ornithine. In general, according to the obtained results, foliar application of ornithine as an important natural compound from a scientific and economic point of view can be a fundamental step towards food security and sustainable agriculture by helping to absorb mineral elements and increasing the activity of antioxidant enzymes. [ABSTRACT FROM AUTHOR]

Peach fruit (Prunus persica L.) was harvested at the stage of commercial harvest and was then treated with 0, 1, 2, 3 mM citric acid (CiA). A factorial model was planned on a completely randomized block design with three replications. Two factors were used in the experimental design, i.e. 4 storage durations × 4 concentrations of CiA. The impact of CiA was evaluated on postharvest quality parameters, decay incidence (DI), vitamin C, total phenolic compounds, and antioxidant capacity, as the peach fruits were maintained in cold storage at 0 ± 0.5 °C and 85-90% relative humidity (RH) for 40 days. By the end of the storage time, peach fruits that were treated with 3 mM CiA showed statistical significance and resulted in the highest values of fruit firmness (FF) (1.75 N), titratable acidity (TA) (0.24%), vitamin C (VC) (3.58 mg.100g-1 FW), total phenolic compounds (TPC) (58.49 mg GAE.100g-1 WF) and antioxidant capacity (AC) (52.96%). CiA treatments significantly controlled the DI by about 30.17 % and remarkably extended the shelf life by about 11.66 days, compared to the control samples during the cold storage. Our findings suggested that using CiA, especially at 3 mM, could be a promising treatment in helping to maintain edibility and to inhibit decay in peach fruits. While these can play an important role in the marketing and export of peach fruits, other benefits include a low cost of the chemical inputs and more safety for human consumption. [ABSTRACT FROM AUTHOR]

Fertilizer type and rate may influence the quality of fruits and vegetables. This study compared plant growth, yield, minerals concentration, and postharvest quality of celery as affected by fertilizer type (organic and chemical) and nitrogen rate. Organic fertilizers were vermicompost (VER) and bio-organic fertilizer [compost plus Trichoderma harzianum (COM)]. Chemical fertilizers were urea (46% N) at high rate [322 kg·ha−1 N (UREA_HIGH)], optimal rate [196 kg·ha−1 N (UREA_OPT)], and low rate [138 kg·ha−1 N (UREA_LOW)]; ammonium nitrate [35% N (AN)] at 196 kg·ha−1 N, and an unfertilized treatment used as a control. Plants fertilized with UREA_HIGH had the highest plant height and yield. Yields with VER and COM were similar to those of UREA_OPT, UREA_LOW, and AN. Celery fed with organic fertilizers had reduced petiole nitrate accumulation and improved mineral content (N, P, and K). Organic fertilizer treatments were the most effective in maintaining celery quality (petiole color, weight loss, titratable acidity, pH, and total soluble solids). There was an enhancement of phytochemical compounds such as vitamin C, total phenols, and antioxidant activity in celery grown with organic fertilizers. Organic fertilizers released N more slowly into the soil, resulting in reduced plant growth and yields but increased celery's nutritional quality. Celery quality attributes with organic fertilizers were similar to those with the UREA_LOW treatment suggesting that the improved celery quality with the organic fertilizers may be attributed to reduced soil N. [ABSTRACT FROM AUTHOR]

The shelf life of horticultural commodities depends on pre‐ and postharvest factors, such as soil fertilization and postharvest handling. The current study aimed to evaluate fresh‐cut celery's postharvest quality as affected by the rate and type (organic and chemical) of nitrogen (N) fertilizer and postharvest treatments. Celery ('Tall Utah') crop was grown in a field in Karaj, Iran. The experimental design was a randomized complete block with three replications and seven preharvest (fertilizer), and five postharvest treatments. Organic fertilizers were vermicompost (VER) and bio‐organic fertilizer [farmyard and livestock manure plus Trichoderma harzianum (COM)]. Chemical fertilizers were urea (46% N) at high rate [322 kg·ha1 N (UREA_HIGH)], optimal rate [196 kg·ha−1 N (UREA_OPT)], and low rate [138 kg·ha−1 N (UREA_LOW)]; ammonium nitrate [35% N (AN)] at 196 kg·ha−1 N; and treatment without fertilization was used as a control. Postharvest treatments included plastic packaging (PP), hydrocooling (HC), blanching (B), and edible coating of psyllium seed mucilage (EC). After postharvest treatments, celery petioles were stored (0–2°C, 85%–90% RH) for 4 weeks and evaluated weekly for quality attributes. Organic fertilizers and UREA_LOW were the most effective treatments in reducing the changes in color, weight loss, titratable acidity (TA), pH, and total soluble solids (TSS) of fresh‐cut celery. Organic fertilizers enhanced the vitamin C content, total phenols, and antioxidant activity in celeries. As postharvest treatments, hydrocooling, plastic packaging, and blanching maintained chroma and hue values. Blanching had the greatest effect on the L* value. Hydrocooling increased celery's TA, TSS, and vitamin C content and reduced weight loss and pH during storage. Thus, celery quality was improved when grown under low or adequate N fertilization. Hydrocooling was an effective postharvest treatment for preserving fresh‐cut celery quality during storage. [ABSTRACT FROM AUTHOR]

Considering the importance of spice plants and their shelf life, as affected by various factors, the current study considered Summer savory plants (Satureja hortensis cv. Saturn) for evaluation under the application of different concentrations of ammonium sulfate (0, 40, 60, 80, and 100 kg/ha) as primary treatments. Based on the plant response, the control group and 100 kg/ha ammonium sulfate were selected as suitable treatments for storage experiments (i.e., storage at ambient, refrigerator, and freezer temperatures for 8 months). Based on the results, the highest percentage and yield of S. hortensis essential oil and biomass occurred in response to 100 kg ammonium sulfate, whereas the lowest amounts were observed in the control group (i.e., in the absence of ammonium sulfate). During the storage period, the essential oil content decreased, but the carvacrol content of the essential oil increased. During the different durations and conditions of storage, the stability of secondary metabolites varied. Essential oil, rosmarinic acid, and carvacrol contents maintained greater stability in plants treated with ammonium sulfate (100 kg/ha), compared with the control group during the storage period. It can be concluded that the preharvest application of ammonium sulfate on S. hortensis improved plant growth and quality indices at preharvest time, while also maintaining the stability of its active ingredients at the postharvest stage and storage time. It also led results to recommend storing Summer savory in the freezer to better preserve its secondary metabolites. [ABSTRACT FROM AUTHOR]

The nutrient uptake, growth and yield of plants depend on nutrients availability in rhizosphere and also on amount of assimilates available in root as carbon skeleton and energy source. Any factor affecting nutrients availability or assimilate partitioning pattern can also affect uptake phenomenon and growth. In this study, the effects of number of flowers per node and nutrient solution concentration on growth pattern and yield of greenhouse cucumber plants were studied using a factorial experiment based on complete randomized block design. Factors consisted of: three levels of number of flowers per node (keeping one, two or three flowers per node) and 5 levels of electrical conductivity of nutrient solution (EC of 1.1, 1.5, 2.15, 2.78 and 3.32 dS/m). Results showed in addition to shoot growth, plants treated with 2.15 EC had higher nitrogen and phosphorous content. The highest yield was observed in plants treated with EC of 1.5 and 2.15 dS/m. Increasing number of flowers per node resulted in increasing in fruit yield in short term (80 days after transplanting) but, no significant differences were observed among treatments when the experiment proceeded (130 day after transplanting). Increase in number of flowers per node led to more allocation of assimilates to fruits, but probably due to low potential of sources this effect of number of flowers on yield has been physiologically controlled. [ABSTRACT FROM AUTHOR]

In this study, the impacts of methyl jasmonate treatment applied by preharvest spray in combination with postharvest immersion on husk and aril antioxidant system of pomegranate fruit during storage at 4±0.5 °C and relative humidity of 90-95 percent, for 120 days during two years was investigated. Methyl jasmonate treatment at 0.2 mM displayed lower husk and aril H2O2 accumulation (36%) due to higher antioxidant enzymes ascorbate peroxidase (34%), catalase (41%) and superoxide dismutase activity (26%), that evetually caused to higher membrane integrity in pomegranate fruit husk. Also, pomegranate fruit treated with methyl jasmonate at 0.2 mM displayed significantly lower husk and aril polyphenol oxidase enzymes activity (47%) than control fruits. Overall, methyl jasmonate treatment can be used as promising technology for maintaining nutraceutical properties of pomegranate fruit partially by promoting antioxidant system activity. [ABSTRACT FROM AUTHOR]

Enzymatic browning is one of the most important reactions that occur in fruits and vegetables, and usually resulting in negative effects on postharvest quality. In order to study the role of some important compounds on apple fruit browning and their changes during the storage, a completely randomized experimental design was conducted in Horticulture Research Center of Tehran University, on Fuji apple trees. In this study, changes of fruit browning, polyphenol oxidase activity, total antioxidant capacity, total phenolic content and the degree of membrane lipid peroxidation during 180 days of storage in 5 time intervals were analyzed. According to the results, total antioxidant capacity and polyphenol oxidase activity did not have significant changes during the first 90 days of storage, but both decreased significantly after 135 days. At the end of 180 days of storage, the lowest enzyme activity was recorded. Total phenolic contents in throughout the storage showed no significant changes. Lipids peroxidation after 90 days of storage increased significantly. Fruit tissue browning in the mid-storage decreased, but after 135 days increased significantly. It can be stated that possibly in the Fuji apple browning, total phenolic content as the enzyme activity is important and in addition to these two factors, lipid peroxidation index is very important in this process too. [ABSTRACT FROM AUTHOR]

To investigate the effect of salicylic acid and iron on peach fruit (Prunus persica L. cv. Zaferani) quality, a factorial experiment in a randomized complete block design with four replications was conducted. Salicylic acid solution at four levels 0, 1, 2 and 4 mM and iron sequestrine in concentrations of 0, 5 and 10 mg/L were prepared and sprayed on peach trees in two stages (40 and 80 days after full bloom). After fruits harvesting, total soluble solids, titratable acidity, pH, firmness, fruit weight loss, antioxidant capacity, ethylene production and electrolyte leakage were measured. The results showed that the treatments compare to controls were prevented weight loss, electrolyte leakage and ethylene production and maintain titratable acids, soluble solids content and antioxidant capacity of fruits. Fruit treated with salicylic acid 4 mM and iron 10 mgl-1 were maintained antioxidant capacity and prevented ethylene production, weight loss and electrolyte leakage. The treated fruits eventually retained their quality until the 40th day and on the 60th day any fruits haven't marketable quality. [ABSTRACT FROM AUTHOR]

In order to evaluate, the effect of different levels of ammonium sulfate on morphological and phytochemical characteristics of summer savory, an experiment based on randomized complete block design (RCBD) with five treatments and three replications on Karaj climate conditions was conducted. The treatment including five levels of ammonium sulfate consist of: control (without fertilizer), 40, 60, 80 and 100 kg/ha of ammonium sulfate that as split application was applied. At full flowering stage, the plant samples of all treatments were harvested and desired factors such as morphological characteristics (plant height, lateral shoot number, plant diameter and stem diameter), biomass, Antioxidant activity, polyphenolic compounds, rosmarinic acid and carvacrol contents were measured. With increasing levels of ammonium sulfate, plant height, number of lateral shoots, plant diameter, stem diameter, internode length and dry matter yield were significantly increased. The highest antioxidant activity was observed in 40 kg ammonium sulfate treatment and increasing in ammonium sulphate concentration was decreased antioxidant activity. The maximum content of rosmarinic acid (10.93 mg per g dry weight) related to 80 kg ammonium sulfate treatment and the lowest content (6.85 mg per g dry weight) was measured in control. The highest amount of carvacrol (6.92 mg per g dry weight) was obtained in 80 kg of ammonium sulfate treatment, followed by 40, 60 and 100 kg treatments on the same level and the minimum content (5.05 mg) in control were detected. According to the results, the treatment of 80 kg/ha of ammonium sulfate, in addition to increasing growth and yield factors, inhansed the amount of carvacrol and rosmarinic acid. [ABSTRACT FROM AUTHOR]

Peach is a highly corrosive fruit with a short shelf life (less than 7 days at room temperature) susceptible to diseases, pathogens and physical damage. The storage or marketable life of horticultural crops can be extended by various treatments applied to them after and/or before harvesting. Fruits are usually treated with a range of materials [(e.g. salicylic acid (SA)] to improve their appearance or delay deterioration. In the present study, effects of pre-harvest treatment of SA (1, 2, and 4 mM) and iron sequestrine (Fe) (5 and 10 mg L-1) on antioxidant capacity, ion leakage, ethylene production, ascorbic acid and carotenoids content of peach fruit (Prunus persica L. Batsch cv. Za'ferani) were examined. The results showed that Fe and SA treatments are effective methods for alleviating ion leakage, weight loss and ethylene production in peach fruit during cold storage. Application of 4.0 mM SA and 10.0 mg L-1 Fe were the most effective treatments to maintain fruits quality parameters. SA and Fe treatments maintained peach fruits quality parameters until 40 days. These results suggest that the SA and Fe treatment are useful materials with potential postharvest application for reducing ethylene production, maintain quality, and improve the health benefits of peach fruit by increasing its antioxidant capacity. [ABSTRACT FROM AUTHOR]

Vegetative traits, chlorophyll content, water use efficiency, nitrogen, potassium and nitrate reductase activity of leaves and root tip were investigated in composition of the melon 'Khatooni' on squash cultivars Ace and Shintozwa under greenhouse conditions. Treatments consisted of melon grafted on squash, melon on melon, squash on melon, squash on squash, melon and squash own-rooted. Results showed that melon grafted on Shintozwa had stem length (408.3 cm), leaf number (38.56), total leaves fresh weight (156.7 g), total shoot fresh weight (132.7 g), leaf area (18517.6 cm2), biomass (247.5 g), leaf dry matter (14.19%), shoot dry matter (7.96%) and root dry matter (17.46%) more than Ace. Grafted melons on both rootstocks were increased water, nitrogen and potassium use efficiency. The amount of total nitrogen and leaf nitrate on Ace rootstock was more than Shintozwa. The leaf ammonium on Shintozwa rootstock was more than Ace. A high nitrate reductase activity of leaves was obtained on melons grafted on Ace rootstock. Nitrate reductase activity in roots was higher than the leaves especially in the case of grafting. Root nitrate reductase activity was demonstrated a negative correlation with shoot length, biomass, leaf fresh weight, shoot fresh weight, leaf total area and root dry matter. Grafted melons totally contain large amount of organic nitrogen were compared to non-grafted, which it related to nitrate reduction and high nitrate consumption. [ABSTRACT FROM AUTHOR]