Reversal of Salt-Induced Oxidative Damage to Buckwheat by Medium Supplementation of Some Nitrogenous and Non-Nitrogenous Stress Relieving Chemicals

Food scarcity is a global issue due to various biotic and abiotic stresses, and salinity stress is a major one. Human activities are adding various salts to agricultural soils, which deteriorate plant growth, development and economic yield. The adverse effects of salinity can be lessened by using various salts in lower amounts. This pot experiment was conducted to improve salt tolerance in buckwheat (Fagopyrum esculentum Moench) by using selected levels of some nitrogenous [potassium nitrate (KNO3; 15 mM), glycine betaine (GB; 160 mM), calcium nitrate (Ca(NO3)2; 0.8 mM) and thiourea (TU; 0.4 mM)] and non-nitrogenous [calcium chloride (CaCl2; 16 mM), potassium chloride (KCl; 6 mM), ascorbic acid (AsA; 2 mM), salicylic acid (SA; 0.4 mM)] compounds hereinafter called as stress relieving compounds (SRCs). Eight kg of loam soil was filled and ten seeds were sown in each pot. Fifteen days after germination, half of the pots were salt stressed with 100 mM NaCl solution in three installments while the remaining half were grown without salt stress. Just after that, selected levels of SRCs were medium supplemented. After 15 days of treatment application, the plants were harvested for estimation of various growth, oxidants [hydrogen peroxide (H2O2) and malondialdehyde (MDA)], antioxidants (vitamins and phenolics) and mineral nutrient contents. Results showed that all parameters were reduced under salinity stress except shoot and root Na+, H2O2, MDA, phenolics, flavonoids and anthocyanins due to salt stress. Application of SRCs alleviated the adverse effects of salt and enhanced the values of attributes by preventing the entry of Na+ into the root and its aerial transport. Among SRCs, for most of the parameters, CaCl2 followed by KCl was more effective, especially under salinity stress. In crux, chlorides of Ca and K were more effective than the other SRCs applied in this study in improving salinity tolerance in buckwheat. The selected levels of SRCs are recommended for growing buckwheat and fetching satisfactory yield in marginally saline soils in future.