Effect of Drought Stress on Lipid Peroxidation,Osmotic Adjustment and Antioxidant Enzyme Activity of Leaves and Roots of <Emphasis Type="Italic">Lycium ruthenicum</Emphasis> Murr. Seedling

Seedling stage is a critical period for survival and growth under drought stress. In the current study, we determined effects of drought stress on physiological and biochemical parameters of leaves and roots of Lycium ruthenicum Murr. seedling. The variables measured were lipid peroxidation (in terms of malondialdehyde (MDA) content), osmotic substances (free proline, soluble protein, and soluble sugar), and antioxidative enzymes (peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT)). Free proline, soluble sugar, and MDA of leaves and roots increased with increasing stress level. Leaves displayed higher accumulations of free proline and MDA than roots. However, roots showed higher total soluble sugar than leaves. Under drought stress, soluble proteins in leaves and roots decreased initially and then increased. Meanwhile, measured proteins were higher in leaves. Under drought stress, SOD, POD, and CAT activities in leaves increased initially and then decreased but increased with increasing drought stress level in roots. Under drought the level of accumulation of osmotics was higher in the leaves than in the roots, while increased activity of antioxidant enzymes persisted in the stressed roots longer that in the leaves.