A comparison of the effects of drought on proline accumulation and peroxidases activity in leaves of Festuca rubra L. and Lolium perenne L.

The effect of soil drought on leaf water content, proline content, and the activity of guaiacol (GuPX) and ascorbate (APX) peroxidases as well as the level of lipid peroxidation were investigated in leaves of drought resistant red fescue (Festuca rubra) and drought sensitive perennial ryegrass (Lolium perenne). Plants were grown under glasshouse conditions in soil pot culture. 26 day-old grasses were exposed to drought by withholding irrigation for 18 days. Water content in leaves of perennial ryegrass decreased more than in red fescue throughout the experimental period. On the other hand, proline content (PC) was higher in red fescue. The activity of APX and GuPX increased in leaves of red fescue, while it did not change in perennial ryegrass. Our data demonstrate that both red fescue and perennial ryegrass were able to survive applied drought, as shown by a lack of stress-induced lipid peroxidation and hence no evidence of oxidative damage. We speculate, that the observed drought stress tolerance at cellular level was associated with the ability to accumulate proline, and to maintain high activity of APX and GuPX, resulting in protection against oxidative damage and lipid peroxidation. It seems that this mechanism works better in red fescue.