Differential growth and antioxidant response to salinity stress in two Indian rice cultivars

The present study investigated the changes in the activity of antioxidant enzymes viz., catalase, peroxidase, superoxide dismutase and glutathione reductase as well as morphological parameters such as root length, shoot length and fresh weight in plants of two rice cultivars (Pusa Sugandha5 and Parmal) under salt treatment (150 mM) for different time intervals (0,6, 18, 24, 30 and 48 h). Results were analyzed in a factorial design based on randomized complete blocks with three replicates. Morphological parameters viz., root length, shoot length and fresh weight showed a decreasing trend with increased duration of stress as compared to the control plants. Increased Catalase activity was found in both the cultivars as compared to the control plants. Peroxidase showed higher activity in Parmal than Pusa sugandha-5. SOD and GR were initially higher up to 24 h of stress and thereafter a declining trend was observed. The plants of cultivar Parmal exhibited higher adaptive potential under salinity stress as evident by the changes in growth parameters and antioxidant defence mechanism as compared to another cultivar, Pusa sugandha-5. These results indicate that, Parmal is salt tolerant with respect to Pusa sugandha-5. The outcome of the present work provides collective information of salinity tolerance in these two Indian rice cultivars. This data would be helpful to researchers engaged in transgenic as well as agricultural institutes. It also helps in a better understanding of physiological and biochemical aspects of salinity adaptation which would help in improvement of agronomically important rice crop.