Low-dose gamma irradiation induces water activity, leaf K⁺/Na⁺, glycine betaine, antioxidant enzyme activity and reduces lipid peroxidation and protease activity to enhance salt tolerance in pigeonpea [Cajanus cajan (L.) Millsp]

Soil salinity is a major constraint that limits legume productivity. The present study evaluates the physiological and biochemical basis of radiation affect on salt tolerance response of pigeonpea. Seed gamma irradiation, in general, at 1.92 (control), 5.86 (80 mM) and 8.02 dSm^-1 (100 mM) soil electrical conductivity (NaCl stress), enhanced seedling establishment, plant growth, carbon metabolism and gas exchange characteristics such as net photosynthesis, stomatal conductance and transpiration rate. Further, an improvement in salt tolerance response of gamma irradiated (<10 Gy) pigeonpea was related to high seed water activity and leaf K⁺/Na⁺, glycine betaine, membrane stability index and enzymic antioxidant activity. (author)