Influence of drought on some physiological parameters symptomatic for oxidative stress in leaves of chives (Allium schoenoprasum)

Drought, created by withholding water, led to significant reductions in the absolute (- 3.6%) and relative (- 24.8%) water content of chives (Allium schoenoprasum) leaves, a significant rise in the osmolarity of the leaf sap (+ 18.9%) and a loss of leaf transpiration (leaf diffusion resistance > 20 s cm(-1)). Nevertheless, the leaves did not show signs of oxidative damage, as the concentration of chlorophylls and soluble proteins and the extent of lipid peroxidation did not change compared with well-watered plants. The concentration of carotenoids and UV radiation absorbing substances remained stable indicating no loss of antioxidant capacity. While it did not affect specific guaiacol peroxidase activity, drought increased the specific activity of ascorbate peroxidase significantly by almost 29% and reduced the specific lipoxygenase activity significantly by 60% Both changes can be considered as beneficial under drought conditions as they potentially reduce the formation of reactive oxygen species. Chives proved to be tolerant to the imposed drought stress, the plants totally recovered within one week after rewatering. (C) 2002 Elsevier Science B.V. All rights reserved.