Assessment of drought stress on barley (Hordeum vulgare L.) seedlings using biochemical parameters

Abstract

On a global scale, drought stress causes a significant threat to plant production. If barley plants experience drought stress at the seedling stage it may reduce plant fitness and affects the grain yield at the final stage of growth. In this study was investigated the relationship between drought and oxidative stress tolerance in barley. Twenty days after germination, two two-row winter barley cultivars NONIUS and NS 565 were exposed to 5 days long drought. The activity of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidise (POD) were determined. Lipid peroxidation and relative electrolyte leakage were investigated as parameters of oxidative stress. When NONIUS seedlings were exposed to drought stress, the antioxidant system could not effectively remove reactive oxygen species, leading to increased lipid peroxidation (an increase from 44.3 to 74.0 nmol/g FW) and damage of membrane (an increase from 8.9 to 23.9%). Drought stress also decreased relative water content (RWC) more in cultivar NONIUS than in cultivar NS 565, and increased proline content, soluble protein, and electrolyte leakage in both cultivar. Proline is effective in increasing the cell turgor and the activity of antioxidant enzymes. When plants were in drought conditions, proline accumulates in both cultivars more than in control.