TIME-DEPENDENT DETERMINATIVE BIOCHEMICAL TRAITS FOR SALT TOLERANCE MECHANISM IN MUNGBEAN (Vigna radiata (L.) R. WILCZEK)

Mungbean is one of the commercially valuable pulse crops. Time-dependent biochemical modulations in the mungbean varieties PKV AKM 12-28 and VBN (Gg)3 exposed to 75, 100, and 125 mM NaCl were estimated, and the results were concluded through multivariate modeling. The cluster analysis gave two fairly distinct clusters that had similar biochemical responses. Results on the principal component analysis suggested that protein content (PC), total phenolic content (TPC), total flavonoid content (TFC), DPPH radical scavenging activity, ABTS radical scavenging activity, proline content (PRC), total free amino acid (TFAA) content, and malondialdehyde (MDA) contents were dominant traits in the shoot as compared to the root. These can be taken as the primary indicators to assess the effect of salt stress on mungbean varieties. The discriminant analysis had identified TFC, MDA, and total sugar content (TSC) as discriminating variables between the roots and shoots. Further, MDA and TFC were identified as discriminating variables under different salt concentrations, and TSC was identified as a discriminating variable at different exposure durations. Discriminant partial least squares analysis further identified optimum biochemical modulations in the shoots of PKV AKM 12-28 and 75 mM NaCl. The salt treatment produced a strong biochemical modulation after 30 and 45 days, which helped plants survive under salt stress. The multivariate approaches efficiently interpreted time-dependent biochemical modulations in shoots and roots of mungbean varieties under salt stress

Silicon alleviates PEG-induced osmotic stress in finger millet by regulating membrane damage, osmolytes, and antioxidant defense

Drought restricts plant growth and productivity. Silicon has beneficial effects on imparting drought tolerance in plants. Present work was intended to evaluate the effect of Si on polyethylene glycol-6000 (PEG) induced osmotic stress in local landraces of finger millet. The seeds of stress-tolerant and stress-sensitive landraces of finger millet were treated with distilled water, 15% PEG, and PEG+Si (5-25 ppm). The ameliorative effect of Si was evaluated in terms of percentage seed germination, seedling growth, accumulation of osmolyte and activity of antioxidative enzymes. PEG-induced osmotic stress reduced seed germination, seedling growth, and augmented osmolyte accumulation. It also elevated the levels of antioxidant enzymes. The exogenous supplementation of silicon significantly improved seed germination as well as early seeding growth. Positive effects of Si were reflected in decline in malondialdehyde (MDA) content and improved glycine betaine content and antioxidant enzymes in PEG-induced stress tolerant as well as susceptible landraces. The Si-induced ameliorated effects on all the parameters studied were more pronounced in the stress-tolerant landrace (FM/ST/01) than the stress-sensitive landrace (FM/RT/01). These results clearly indicate advantageous effects of Si in relieving PEG-induced stress during seed germination and early seeding growth and suggest a possibility of better stand establishment by application of silicon containing fertilizer during seed sowing