The effect of salinity on the activity of some enzymes and accumulation of osmotic protectants in some cotton cultivars

To evaluate the effect of salinity on accumulation of amino acids and the activity of antioxidant enzymes in some genotypes of cotton (Gossypium hirsutum L.) an experiment in a randomized complete block design with three replications was conducted in Anbar Olum’s research farm which is located in Golestan province. Treatments consisted of seven genotypes of cotton namely;Çukurova, opal, Shyrpan 539, 43200, Ciland, and a Sepid in a saline soil with the EC equivalent to 14.8 dS/m.The Voshmgir’s dam water was used for irrigation having the salinity of 2.5-3 dS/m. The 5th and 6thleaves and thirty days’ stems samples were taken. The results showed that the soil salinity had a significant effect on yield and physiological traits genotypes with more severe stress and activity of catalase, peroxidase, polyphenol oxidase and amino acids proline and glycine betaine increased. Among the genotypes, the activity of peroxidase, proline and glycinebetaine was a significant difference with 99% of confidence and the activity of catalase and glycinebetaine in Sepid genotype was higher but the Opal genotype showed a higher amount of peroxidase activity and proline content. According to the results collected from the field, the Opal genotype with 2256 kg/ha of seed cotton yield had the highest and the Çukurova with 1399 kg/ha of seed cotton yield had the lowest performance.