Growth and Physiological Responses of Peanut Seedling to Salt Stress

Soil salinity plays a primary role in soil degradation and reducing agricultural productivity.This study was conducted to evaluate the effects of salinity stress on growth, photosynthesis and antioxidative enzyme activity in functional leaves of two peanut cultivars (Huayu 23 and Yueyou 40) were sown under five salinity levels i.e., 0.96, 2.35, 3.34, 4.82 and 6.70 dS/m; 0.96 dS/m being taken as control.With increasing salinity levels, peanut shoot and root dry weight significantly decreased in both cultivars.Chlorophyll contents, photosynthesis, the maximum fluorescence (F v /F m ) and photochemical quenching (qP) declined with increasing soil salinity and decrease was more in salt-sensitive Yueyou 40 than salt-tolerance cultivar Huayu 23.Compared to salt-tolerance (Huayu 23), salt-sensitive cultivar Yueyou 40 observed more decrease of peanut growth.Moreover, SOD and CAT activity of peanut leaves was linearly increased with higher salinity in both cultivars.In contrast, nonphotochemical quenching (NPQ) increased with increasing salinity levels, especially in salt-sensitive cultivar Yueyou 40.However, POD activity was not affected by soil salinity in Huayu 23, but significantly decreased by increasing salinity level in Yueyou 40.In conclusion, the salt-tolerance variety adapted well saline environment by reducing photoinhibition and diminishing capacity for electron transport and maintaining relatively high level of chlorophyll content and antioxidant enzyme activities.