Effect of 2, 2'-Bipyridyl on Ethylene-enhanced Chlorophyll Catabolism in Citrus unshiu Fruit

Abstract

The effect of 2, 2'-bipyridyl on ethylene-enhanced degreening in Citrus unshiu fruit was investigated. In ethylene-treated fruit, 2, 2'-bipyridyl inhibited the enhanced degreening process and did not cause the accumulation of phytol-free catabolites, chlorophyllide a, and pheophorbide a, but on the contrary, induced the accumulation of chlorophyll (Chl) a, Chl b, and pheophytin a, 2, 2'-Bipyridyl inhibited ethylene-enhanced chlorophyllase (Chlase) activity, but it had no effect on the enzyme in vitro. These results indicate that 2, 2'-bipyridyl inhibits the induction of Chlase, which is the key enzyme in the initial step of Chl catabolism and the degreening in ethylene-treated Citrus unshiu fruit.