Chitosan and Chitosan Nanoparticles Differentially Alleviate Salinity Stress in Phaseolus vulgaris L. Plants.

Salinity stress can significantly cause negative impacts on the physiological and biochemical traits of plants and, consequently, a reduction in the yield productivity of crops. Therefore, the current study aimed to investigate the effects of chitosan (Cs) and chitosan nanoparticles (CsNPs) to mitigate salinity stress (i.e., 25, 50, 100, and 200 mM NaCl) and improve pigment fractions, carbohydrates content, ions content, proline, hydrogen peroxide, lipid peroxidation, electrolyte leakage content, and the antioxidant system of Phaseolus vulgaris L. grown in clay-sandy soil. Methacrylic acid was used to synthesize CsNPs, with an average size of 40 ± 2 nm. Salinity stress negatively affected yield traits, pigment fractions, and carbohydrate content. However, in plants grown under salt stress, the application of either Cs or CsNPs significantly improved yield, pigment fractions, carbohydrate content, proline, and the antioxidant system, while these treatments reduced hydrogen peroxide, lipid peroxidation, and electrolyte leakage. The positive effects of CsNPs were shown to be more beneficial than Cs when applied exogenously to plants grown under salt stress. In this context, it could be concluded that CsNPs could be used to mitigate salt stress effects on Phaseolus vulgaris L. plants grown in saline soils.

Seedless okra pod, chlorophyll, vitamin C and mineral content development using plant growth regulator in vitro and in vivo culture.

Vegetables are rich in vitamins, minerals and dietary fiber that keep a significant role in the functioning of the human body to refrain human health benefits. The experiment was carried out to investigate the effect of different concentrations of IAA on the seedless pod, chlorophyll, vitamin and mineral content of okra as human health benefits. The innovative seed soaking method of application using 0, 25, 50, 100 & 200 mg/l of IAA concentrations was used in okra before germination and cultured in vitro and in vivo. The lower concentrations (25 and 50 mg/l) of IAA significantly increased the pod setting compared to the higher concentration (100 and 200 mg/l). The higher concentration (100 and 200 mg/l) had lower fruit settings than the lower concentration (25 &50) had higher fruit settings. The higher pod size was obtained in the concentration of 100 & 200 mg/l of IAA (34.18 cm²) as compared to the control and other concentrations. In addition, the highest soluble solid content was obtained by 100 and 200 mg/l of IAA concentration as compared to the other concentrations. The maximum vitamin C was found in the concentration of 100 mg/l of IAA as compared to the control and other concentrations. Moreover, higher mineral contents like K, Ca, Mg, Na and Fe were found in 100 & 200 mg/l of IAA. The higher concentrations (100 and 200 mg/l) of IAA greatly increased the seedless okra percentage as compared to the lower concentration. It seemed that 100 and 200 mg/l concentration IAA was a better concentration for mineral content and seedless okra production as compared to the other concentrations.

Mycorrhizal Effects on Growth and Expressions of Stress-Responsive Genes (aquaporins and SOSs) of Tomato under Salt Stress.

Environmentally friendly arbuscular mycorrhizal fungi (AMF) in the soil can alleviate host damage from abiotic stresses, but the underlying mechanisms are unclear. The objective of this study was to analyze the effects of an arbuscular mycorrhizal fungus, Paraglomus occultum, on plant growth, nitrogen balance index, and expressions of salt overly sensitive genes (SOSs), plasma membrane intrinsic protein genes (PIPs), and tonoplast intrinsic protein genes (TIPs) in leaves of tomato (Solanum lycopersicum L. var. Huapiqiu) seedlings grown in 0 and 150 mM NaCl stress. NaCl stress severely inhibited plant growth, but P. occultum inoculation significantly improved plant growth. NaCl stress also suppressed the chlorophyll index, accompanied by an increase in the flavonoid index, whereas inoculation with AMF significantly promoted the chlorophyll index as well as reduced the flavonoid index under NaCl conditions, thus leading to an increase in the nitrogen balance index in inoculated plants. NaCl stress regulated the expression of SlPIP1 and SlPIP2 genes in leaves, and five SlPIPs genes were up-regulated after P. occultum colonization under NaCl stress, along with the down-regulation of only SlPIP1;2. Both NaCl stress and P. occultum inoculation induced diverse expression patterns in SlTIPs, coupled with a greater number of up-regulated TIPs in inoculated versus uninoculated plants under NaCl stress. NaCl stress up-regulated SlSOS2 expressions of mycorrhizal and non-mycorrhizal plants, while P. occultum significantly up-regulated SlSOS1 expressions by 1.13- and 0.45-fold under non-NaCl and NaCl conditions, respectively. It was concluded that P. occultum inoculation enhanced the salt tolerance of the tomato, associated with the nutrient status and stress-responsive gene (aquaporins and SOS1) expressions.

Non-destructive assessment of flesh firmness and dietary antioxidants of greenhouse-grown tomato (Solanum lycopersicum L.) at different fruit maturity stages.

Non-destructive methods have been widely recognized for evaluating fruit quality traits of many horticultural crops and food processing industry. Destructive (analytical) test, and non-destructive evaluation of the quality traits were investigated and compared for 'Red Rose' tomato (Solanum lycopersicum L.) fruit grown under protected environment. Fresh tomato fruit at five distinctive maturity stages namely; breaker (BK), turning (TG), pink (PK), light-red (LR), and red (RD) were labeled and scanned using the handheld near infra-red (NIR) enhanced spectrometer at a wavelength range of 285-1200 nm. The labeled tomato samples were then measured analytically for flesh firmness, lycopene, ß-carotene, total phenolic content (TPC) and total flavonoids content (TFC). The results revealed that quality traits could be estimated using NIR spectroscopy with a relatively high coefficient of determination (R2): 0.834 for total phenolic content, 0.864 for lycopene, 0.790 for total flavonoid content, 0.708 for ß-carotene; and 0.679 for flesh firmness. The accumulation of Lyco and ß-Car rapidly increased in tomatoes harvested between the TG and the LR maturity stages. Harvesting tomatoes at BK maturity stage resulted in significantly higher flesh firmness than harvesting at the later maturity stages. Tomato fruits had the lowest TPC and TFC contents at the earliest maturity stage (BK), while they had intermediate TPC and TFC levels at LR and RD maturity stages. NIR spectroscopic measurements of fruit firmness and lipophilic antioxidants in tomato fruit at various maturity stages were partially in accordance with those estimated by destructive (analytical) methods. Based on these findings, we recommend using non-destructive NIR spectroscopy as an effective tool for predicting tomato fruit quality during harvest stage and postharvest processing.

Improved functional and nutritional properties of tomato fruit during cold storage.

The use of synthetic antioxidants has been associated with serious concerns for human and environmental health. During ripening stages, tomato fruit is exposed to different abiotic stresses which not only influence its nutritional, mechanical, and functional properties at harvest, but also affect the quality and shelf life of the fruit during storage. This study investigated the pattern of changes in dietary antioxidants during various ripening stages of tomato fruit (cv. Red Rose) and their impact on storage behavior of the fruit during cold storage. Tomato fruits were harvested at mature green, breaker, turning, pink, light-red and red stages of maturity. Then, they were analysed for flesh firmness, soluble solids content, titratable acidity, total sugars, pH, dry matter content, lipophilic (lycopene, ß-carotene, and total carotenoids), and hydrophilic (ascorbic acid, phenolic and flavonoids) antioxidants. Additional fruits were harvested at each maturity stage and divided into three equal lots, then were subjected to low-temperature (10 ± 1 °C) storage with 80 ± 5% RH, for 7, 14, and 21 days. Flesh firmness, and the levels of dietary antioxidants were analysed following the subsequent storage periods. The results revealed that the peak of hydrophilic antioxidants such as ascorbic acid, phenolic compounds, and flavonoids was between the 'pink' and the 'light-red' stages of fruit maturity. Whereas tomatoes harvested at the 'red' stage of maturity had the highest levels of lycopene and ß-carotene. Both the stage of fruit maturity at harvest and duration of cold storage influenced flesh firmness, organoleptic and functional properties of 'Red Rose' tomato fruit. In conclusion, the results of the current investigation have practical implications in formulating foods with improved functional properties at processing industries.