Peroxidase activity and lipid peroxidation in strawberry (fragaria x ananassa) plants under low temperature

Abstract

The activity of peroxidase (PRX) isozyme, lipid peroxidation (Malondialdehyde, MDA content) and cell membrane injury were studied during low temperature treatment for different periods in strawberry (Fragaria x ananassa cv. Camarosa) leaf tissues. Seedlings were grown for six weeks (plants had 4-5 leaves) in a greenhouse then the plants were transferred to a climate chamber with constant 5o C, 60% relative humidity, 14/10 h (light/dark) photoperiod regime and 4 LS light intensity for 1, 4, 7 or 10 days to impose a low temperature stress. In general, low temperature application during 10 days caused a linear increase in MDA content. Native polyacrylamide gel electrophoresis (PAGE) of both acidic and basic peroxidase (PRX) isozymes yielded a single sharp protein band with Rf=0.23 and Rf=0.17, respectively. In addition data indicated a strong relationship between band intensities and the duration of the low temperature treatment. However, the considerable increase of PRX activities could not stop the deleterious effects of low temperature, but reduced severity of stress, thus showing a reduction in the percentage of injury on the 7th day which is correlated with cold-acclimation of strawberry leaf tissues under low temperature.