ALTERATIONS IN LIPID COMPOSITION, LIPID PEROXIDATION AND ANTI-OXIDATIVE PROTECTION DURING SENESCENCE IN DROUGHT STRESSED PLANTS AND NON-DROUGHT STRESSED PLANTS OF PISUM SATIVUM

摘要

Pea (Pisum sativum) plants were deprived of water for successive periods. The aging process in control plants was followed simultaneously. Leaves were sampled from plants of different age. The lipid content and composition, lipid peroxidation and activities of enzymes implicated in anti-oxidative defence, superoxide dismutase and glutathione reductase were analysed. The drought treatment caused the senescence to start earlier and being more rapid. An increase in the activities of superoxide dismutase and glutathione reductase was found at the onset of senescence, followed by a decrease at advanced senescence. The polar acyl lipids decreased and the neutral acyl lipids increased during senescence in both treatments. The drought stressed and non-drought stressed plants showed a similar pattern of changes during senescence, though of different magnitude and rate. However, there was a relatively higher proportion of neutral lipids in the leaves of drought stressed plants compared to non-drought stressed plants, accompanied by a lower level of lipid peroxidation, which might indicate an inhibition in the degradation of neutral lipids. [References: 44]