No abstract

No abstract

The effect of melatonin (MT) on potato plants under drought stress is still unclear in the available literature. Here, we studied the effect of MT as a foliar application at 0, 0.05, 0.1, and 0.2 mM on potato plants grown under well-watered and drought stressed conditions during the most critical period of early tuberization stage. The results indicated that under drought stress conditions, exogenous MT significantly (p ≤ 0.05) improved shoot fresh weight, shoot dry weight, chlorophyll (Chl; a, b and a + b), leaf relative water content (RWC), free amino acids (FAA), non-reducing sugars, total soluble sugars, cell membrane stability index, superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (G-POX), and ascorbate peroxidase (APX) compared to the untreated plants. Meanwhile, carotenoids, proline, methylglyoxal (MG), H2O2, lipid peroxidation (malondialdehyde; MDA) and abscisic acid (ABA) were significantly decreased compared to the untreated plants. These responses may reveal the protective role of MT against drought induced carbonyl/oxidative stress and enhancing the antioxidative defense systems. Furthermore, tuber yield was differentially responded to MT treatments under well-watered and drought stressed conditions. Since, applied-MT led to an obvious decrease in tuber yield under well-watered conditions. In contrast, under drought conditions, tuber yield was substantially increased by MT-treatments up to 0.1 mM. These results may imply that under water deficiency, MT can regulate the tuberization process in potato plants by hindering ABA transport from the root to shoot system, on the one hand, and by increasing the non-reducing sugars on the other hand.

Two field experiments were carried out during 2017/2018 and 2018/2019 seasons, at the Experimental Farm, Faculty of Agriculture, New Valley University, New Valley governorate, Egypt, to study the effect of nitrogen levels (30, 45 and 60 kg/fed.) and micronutrients foliar application: control (B 0 + Mo 0), boron at 100 ppm (B 100), molybdenum at 50 ppm (Mo 50) and combined boron and molybdenum (B 100 + Mo 50) on cauliflower vegetative growth, yield, and quality parameters in the recently reclaimed areas, especially New Valley governorate as a promising area for agriculture expansion in Egypt. The results revealed that nearly all traits showed a gradual increment with increasing the nitrogen level; whereas the application of high level of nitrogen (60 kg/fed.) significantly increased vegetative growth, curd yield and curd quality of cauliflower and significantly decreased total phenols content and has no effect on number of days to maturity. Also, the results of this study reported promotional effects of either B or Mo foliar application on growth, yield and quality of cauliflower curds compared with untreated plants; nevertheless the combined application of B and Mo together was more effective than application of B or Mo when they separately applied. Moreover, inorganic nitrogen at 60 kg/fed. was more effective in the presence of B and Mo at 100 and 50 ppm, respectively, than the other combinations and achieved the highest curd yield with top quality.

to study the effect of five types of polypropylene packages (non-perforated, perforated with 8, 16, 24 and 32 microholes) on storability and quality of dill during cold storage for 7, 14, 21 and 28 days at 0±1°C, in addition to 2 and 4 days at 10±1°C as shelf life. Weight loss, appearance, off-odor, taste, total chlorophyll, ascorbic acid, soluble solids content (SSC), total sugars content and total phenolic were measured. The results indicated that the microperforated polypropylene package with 24 microholes had the best taste and appearance, and the highest total chlorophyll, ascorbic acid, sugars and phenolic and lowest off-odor during the cold storage period at 0±1 °C for 28 days and shelf life for 4 days at 10 ± 1°C in comparison with the other packages. At the end of cold storage and period of shelf life, the microperforated polypropylene package with 24 microholes maintained the quality of dill.