Effects of salinity on growth, antioxidant enzymes activity and ions accumulation in Puccinellia distans (jacq.) parl

Puccinellia distans is a perennial، salt tolerant forage species that belongs to Poaceae family. The main objective of the present study was to evaluate the effect of different levels of salinity ongrowth، antioxidant enzymes activity and mineral accumulationin Puccinellia distans. The experiment was conducted based on a completely randomized design with five replications in green house. Salinity levels included 0، 100 and 200 mM NaCl. Plants were harvested before reproductive stage. The results indicated that salinity imposed significant reduction in growth of plants including shoot and total length، fresh and dry weight، leaf number and relative water content. Concentration of Na+ decreased and concentration of K+ and K+/Na+ ratio increased due to salinity in both shoots and roots. The activity of catalase and polyphenol oxidase decreased in shoots of plants treated with 200 mM NaCl compared to control، however، the activity of catalase، cell wall and soluble peroxidase، and polyphenol oxidase in roots and cell wall peroxidase in shoots of plants indicated significant increase due to the same salt treatment. Salt treatments led to increase of chlorophyll a، total chlorophyll and carotenoids contents and the amount of hydrogen peroxide. However، no significant change was observed in the amount of lipid peroxidation in roots and shoots. The results indicated that in spite of growth retardation and Na+ accumulation، salt treatments did not induce oxidative stress in Puccienellia distans. The reduction of K+ concentration، K+/Na+ ratio and relative water content may cause decrease of plant growth.