The Elementary Research Of The Mechanism That Ethephon Introduced The Litchi's Shoot To Defoliation

Four varieties of litchi shoot were studied in this experiment. After spraying ethephon with different concentration, such as o, 200,400 mg/1 on the shoot, the shape of the leaves ,the activity of IAA oxidase , peroxidase ,the content of the protein and the secondary substance were analyzed. It was resulted that:l.The influence to the shape of shoot and the time leaves desquamated was different according to the different treatment concentration of ethephon.2.If it was rain in four hours after treatment, the shape of leaves was the same between the treatment and control. In the environment with high temperature and humidity, there was little leaves to desquamate just after 3 days.3.Different variety was expressed different sensitivity to ethephon. The trend of enzyme activity and content of protein existed discrepancy.4.The environment changes had some influences to IAA oxidase after treating with ethephon.5."Feizixiao" of the same seasons and different years was treated with ethephon. The results showed that the trend of IAA oxidase activity is basically consistent. After treatment, IAA oxidase activity is higher than that of the contrast and then the treatment was some differences between 200mg/l and 400 mg/1.6."Feizixiao" of the different seasons and different years was treated with ethephon. The results showed that the trend of IAA oxidase activity and content of protein had expressed differences, especially among different treatments with ethephon in on trial. In spring and winter, the variant trends and degrees of IAA oxidase and peroxidase activities were basically consistent, the activities increased at first and then decreased. In summer and autumn, the variant trends were also consistent, all the activities increased constantly. The variance of protein content was more complicated: the variant trends of treated with 200 mg/1 ethephon were consistent in all seasons. It increased at first then decreased before the 12th hours and increased then decreased to get a minimum after the 12th. The variance of protein content treated with 400 mg/1 ethephon was not as stable as treated with 200mg/l ethephon. In spring, it increased constantly. In autumn , it decreased constantly. In summer and winter, it increased firstly then decreased. However , the protein content of summer treetop reach a peak at the 12th hours, afterward it decreased dramatically and the degree is bigger than in winter, The variant trends of anzyme activities and protein content were almost the same in contrast. IAA oxidase activityalmost didn't vary too much in the 24th hours in the experiment. The peroxidase activtity and protein content all increased firstly and then decreased, but the variance was not big from the beginning to the end.7.There were some relation between IAA oxidase and peroxidase. By analyzing the trend of IAA oxidase activity and peroxidase activity and the time starting up, the results showed that IAA oxidase and peroxidase was synchronous.