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