Effect of salt stress on growth, physiological and biochemical parameters and activities of antioxidative enzymes of rice cultivars

Salinity is a key abiotic stress that limits the plant growth and productivity of crops worldwide. In this study, variations in the growth, physiological and biochemical parameters, and antioxidant defense systems under saline soil conditions among three rice cultivars (Ahlami-Tarom, Salari, and Binam) were investigated. Our results indicated that the all rice cultivars had normal growth and yield under control conditions. All the parameters tested were significantly different in the environments studied (stress vs. control). For all three genotypes, salinity induced a significant decrease in growth characteristics, chlorophyll content and grain yield. By contrast an increase in lipid peroxidation and activity of antioxidant enzymes were observed in all rice cultivars. Among the cultivars studied, Binam genotype with the highest increase in the activity of antioxidant enzymes such as catalase, ascorbate peroxidase, and peroxidase, the lowest increase in malondialdehyde content and smaller drop in chlorophyll content showed better protection against salt stress, which made it possible to maintain a higher yield even under stress conditions. The findings of the present study suggested that the activity of antioxidant enzymes can act as an efficient defense mechanism to deal with salinity stress, and accordingly, the potential tolerance of Binam cultivar with a good antioxidant defense system increases its yield compared to other cultivars under salinity stress conditions.