Activity Distribution and Change of Superoxide Dismutase in Major Tissues of Citrus during the Middle and Late Growth Stages

SOD activities in peel,pulp,seed and leaf tissues from 16 citrus varieties were measured.The distribution of SOD activity in citrus tissues and the change of SOD activity during citrus growth period were analyzed.The results showed that SOD activity was detected in all the four citrus tissues with significant differences among them and decreased in the following order: leaf seed peel pulp.Significant differences in SOD activity were observed for the same tissue among some of the citrus varieties studied.During the middle and late growth stages,SOD activity showed diverse changing trends within a narrow range with increasing degree of maturity;SOD activity in seed and leaf tissues revealed an increasing trend.