Role of chitosan in reducing the effects of salinity stress through enzymatic and non-enzymatic antioxidants in Portulaca oleracea L.

Portulaca oleracea L. is a medicinal plant of the family Portulacaceae. Salinity stress is one of the most important factors limiting the growth and development of plants, especially in arid and semi-arid regions. Chitosan is a biological elicitor and is a major component of the cell wall of many species of fungi. In this study effects of salinity and chitosan stress on physiological parameters and growth parameters of the Portulaca oleracea L were studied. The experiment was arranged in a randomized complete design with 3 replications. For this purpose, the plant was exposed to different treatments of NaCl (0, 25 and 35 ds m-1), chitosan (0, 0.2 and 0.4 g l-1) Plants were harvested after treatment. Different morphological and physiological parameters were studied for different treatments. By measuring growth parameters and according to broiler and halophytic characteristics of the plant, the salinity 25 ds m-1 as a favorable growth and salinity 35 dsm-1 showed a decrease in growth in the plant. Salinity stress increased catalase enzyme activity, peroxidase, polyphenoloxidase and flavonoid content but reduced anthocyanine. Interaction of salinity and Chitosan increased growth of purslane, phenol, peroxidase, polyphenoloxidase enzyme activity and reduced catalase enzyme activity and anthocyanine content. In this study chitosan is improving agent in stress conditions and improved the physiological and biochemical traits associated with oxidative stress. Considering the growing salinity of the country, it is important to use the elicitors, especially chitosan, as a biopolymer that reduces the effects of salinity stress on the Portulaca oleracea L.