EFFECTS OF P DEFICIENCY ON PROTECTIVE ENZYME ACTIVITY AND MEMBRANE LIPID PEROXIDATION IN DIFFERENT TOMATO GENOTYPES

Abstract

The protective enzyme activity and membrane lipid peroxidation in leaves at different P levels in nine tomato genotypes collected from the world were studied in nutrient solution culture. Phosphorus deficiency decreased leaf Chl contents. Compared with the control, there was a slight change of catalase activities in tomato seedlings under P deficiency, but superoxide dismutase activities, peroxidase activities and membrane-lipid peroxidation contents increased in phosphorus deficiency seedlings. There were differences in SOD activities, POD activities and MDA contents among tomato genotypes. The SOD activities under P deficiency stress in No. 4 and No. 54 increased more than that in No. 46, No. 2738 and No. 37 as compared with control seedlings. POD activities under P deficiency stress in No. 27, No. 37 and No. 46 increased more than that in No. 4, No. 25 and No. 2738. MDA contents under P deficiency stress in No. 2, No. 4 and No. 2738 increased more than that in No. 25, No. 27 and No. 37 as compared with control seedlings. These results indicated that the possible role of SOD activities, POD activities and MDA contents as anti-oxidant protector systems for tomato plants under phosphorus deficiency. Moreover, they suggest the possibility of using these enzyme activities as an additional screening criterion for detecting phosphorus efficiency in tomato genotypes.