Abstract:Ethylene production rates and 1-aminocyclopropane-1-carboxylic acid (ACC) synthetase activities were 0. 78,0.91 nl· g-l ·h-land 0.02,0.05 nmol·g-1·h-1 respectively in the peel and pulp of newly harvested banana fruits(Musa acuminata Colla “warf cavendish”),their ethylene-forming enzyme(EFE)activities were yet as high as 10.5 and 5.1 nl·g-1·h-1. When the fruits were chilled at 1.5℃ ,the ethylene production and EFE activities of the peel and pulp kept decreasing with the time course of chilling treatment. However, after these chilled fruits were transferred to 20℃ for 24 h,their ACC synthetase activities increased markedly,and ethylene production had separate peaks(1.75 and 2.45 nl·g-1 ·h-1) in the peel and pulp. In this case,the endogenous low content of S-adenosylmethionine (SAM)in vivo was insufficient for its ACC synthesis, The inhibitory effect of cycloheximide on ACC synthesis showed that chilling-induced ethylene production was mainly the result of activity of the resynthesized ACC synthetase induced by chilling treatment. The production of chilling-induced ethylene could be good indicator of chilling injury, but it is unlikely an indicator of chilling damage during ripening process in banana. In the severly chilling-injured fruits, both the peel and pulp still had the capability of converting ACC to ethylene.