Effect of salinity on some physiological and biochemical parameters in explants of two cultivars of soybean (Glyicine max L.)

Abstract

     Effect of NaCl on fresh mass, contents of sugars, free proline, protein, activity of polyphenol oxidase (PPO) and peroxidase (POD) in explants of two cultivars (Hack and Zan) of soybean were investigated. Explants were grown for one month in medium with different NaCl concentrations (0, 50, 100, 150 and 200 mM). Fresh mass of explants in both cultivars decreased continuously with an increase in salinity. Proline, reducing sugars, soluble sugars and total sugars contents enhanced under salinity in both cultivars. Oligosaccharide content in both cultivars increased up to 50 mM and declined at higher salinities. Polysaccharide of Hack explants increased up to 100 mM and then diminished, but in Zan explants, it reduced at 50 mM and increased at higher salinities. Protein content in Hack improved by salinity but in Zan explants, protein content decreased up to 100 mM NaCl and then increased at higher salinities. PPO activity in two cultivars increased up to 150 mM NaCl and then decreased. POD activity in both explants increased up to 200 mM NaCl. Fatty acid composition was modified by salinity. Saturated fatty acids content in explants of both cultivars declined but unsaturated fatty acids content (linoleic and arachidonic acid) improved under salinity. These results showed that cv. Hack exhibit a better protection mechanism against salinity damage and more salt-tolerant by maintaining and/or increasing fresh mass, osmolyte accumulation and activity of antioxidant enzymes than cv. Zan.