Abstract: The decrease of ascorbic acid content was observed in tile pericarp and juice of litchi fruit after picking from 0 to 7 days. Change of glutathione content in juice was similar to the change of ascorbic acid, but it increased in the pericarp within first 3 days after pieking, and then decreased. During the period of experiment, malondialdehyde, a product of lipid peroxidation, increased significantly, it was 3 times in the 7th day after picking as compared with the initial content. The activity of superoxide dismutase decreased as malondialdehyde accumulated. A rapid increase of peroxidase activity in pericarp after picking would be associted with the senescence of litchi fruit. These results suggest that the senescence of litchi fruit might be damaged by active oxygen. The increase of peroxidase activity and malondialdehyde content may be useful as a detector of fruit senescing.

Key words: Litchi fruit, Oxidation and peroxidation