Exogenous spermidine alters in different way membrane permeability and lipid peroxidation in water stressed barley leaves

In order to see whether polyamines will modify membrane functioning in the water stressed plants, barley (Hordeum vulgare) seedlings were treated with spermidine (Spd) prior to dehydration and then the stress-evoked changes in membrane permeability (i.e. in electrolyte leak age from leaves) and lipid peroxidation (indicated by modifications of the malondi -aldehyde (MDA) level, and of the lipoxygenase (LOX) activity) were fol lowed. The Spd treatement lowered in jury index in plants subjected to water deficit, al though it slightly in creased the stress-promoted LOX activity and in creased the MDA level in the studied leaves. Presented results confirm that spermidine stabi lizes plant membranes under water stress conditions. However, this effect does not seem to be asso ciated with the Spd-induced modifications in the lipid peroxidation activities.