龙眼生理落果中的纤维素酶、果胶酶活性及脱落酸含量

CELLULASE AND PECTINASE ACTIVITIES AND ABA CONTENT IN DROP FRUITS OF LONGAN

水涨龙眼脱落幼果的纤维素酶活性与落果比率之间具显著相关性（r=0．886）。在生理落果期间，脱落幼果纤维素酶活性高出正常幼果37％。果胶酶活性对生理落果的影响不甚明显，仅在落果中期表现出较强酶活性。在整个生理落果期间，脱落幼果脱落酸含量始终处在高于正常幼果的状态，其含量比正常幼果的脱落酸含量高167倍。幼果中纤维素酶活性强和脱落酸含量高是促进水涨龙眼生理落果的重要因素。

Physiological fruit drop of longan (Dimocarpus longan Lour. cv. Shuizhang) wasstudied by measuring the cellulase and pectinase activities and ABA content in juvenile fruitscollected from 5 trees of 15 years old in Fujian Province in May 1993. The results showedthat there was a significant relationship between cellulase activity and fruit dropping.Cellulase activity in drop fruits was significantly higher than that in normal ones. No obvi- ous difference in pectinase activity' between normal and drop fruits was found, and thepectinase activity was slightly enhanced in drop fruits only at middle stage of fruitdropping. The content of ABA in drop fruits was higher than that in normal fruits. It wasshown that higher content of ABA and higher cellulase activity promote-d physiological dropof longan juvenile fruits.