Ameliorative effects of nitric oxide on growth, physiology and biochemistry of chickpea plants under salinity stress

Salinity is one of the major environmental constraints affecting agriculture in major regions of the world. This study was conducted to evaluate the effect of exogenous nitric oxide (NO) treatments on two chickpea cultivars (Cagatay and Inci) under salt stress conditions. Different NO doses (0. 75 and 100 mu M sodium nitroprusside (SNP)) as an NO source were applied to chickpea plants grown under saline (presence of 50 and 100 mM of NA]) and nonsaline conditions. In this study, plant shoot fresh and dry weight, root fresh and dry weight, chlorophyll a, b, total chlorophyll, chlorophyll reading value (CRV), relative water content (RWC), electrical conductivity (EC), malondialdehyde (MDA), hydrogen peroxide (H2O2) antioxidant enzyme activity (superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX)], K/Na and Ca/Na ratio were examined. Plant growth, RWC, and chlorophyll content were negatively affected by salinity conditions but exogenous NO treatment improved the parameters. EC, H2O2, and MDA content were increased with salinity conditions while exogenous NO treatment decreased the searched parameters. K/Na and Ca/Na ratios were decreased with 50 and 100 mM of NaCl treatments. Although the cultivars response to salt stress is similar in general, Inci cultivars were found to be more sensitive to salt stress than Cagatay cultivar. The present study revealed that the exogenous NO treatment supported chickpea seedlings against salinity stress by regulating uptaking mineral elements, the antioxidant enzyme activity, and RWC.