The Effect And Mechanism Of The Flower-Bud Of The Off-Season In Longan Induction By Potassium Chlorate Application

Shixia Longan (Dimocrupus longan Lour. cv. Shixia.) trees were treated with potassium chlorate(KClO₃) and KClO₃ plus paclobutrazol (PP₃₃₃). It aims to research the relationship between the effects of the flower-bud induction on Longan by potassium chlorate application, and the change of the plants' C/N, nutrient elements, as well as endogenous hormones. The results showed:1. Flower-bud formation can be induced by both treatments of KClO₃ and KClO₃ plus PP333. The percent of flower-bud formation was quite difference in different years, the highest reach to 38.78%, and the lowest is 7.61%. The inducing effect of the treatment of KCLO₃ plus PP₃₃₃ was better than of KClO₃ only. But it's heading time was put off obviously. What's more, there are a low percent of trees with flowers in all treatments, only 33. 3%⁶6. 7%, and the headings were appeared in different batch.2. From treatment to flower-bud physiological differentiation, the biosynthesis of endogenous ethylene, ABA and ZT went up, and the content was higher than control. Nevertheless, the contents of 6A and IAA descended. During the periods of morphological differentiation, the contents of ethylene, ABA and ZT were on a trends of declined, but GA and IAA were went up. There was an obv i ous correlativity between the contents of ethylene, ABA and ZT and flower-bud formation.3 . During the periods of flower-bud physiological differentiation, the ratio of ABA/GA, ABA/IAA, ZT/IAA and ZT/GA was higher than control. But during the periods of flower-bud morphological differentiation, besides ZT/IAA, the ratio of ABA/GA, ABA/IAA and ZT/GA was on a trend of decline.4. After treatment, the contents of nitrogen were ascending at the prophase, then kept on a high level. The change of control was similar to the treatment. The change of sugar's content was on a trend of descending on the whole. Control goes down just I ike the same. But it was higher than the treatment. There was an obvious negative cor relativity between the contents of sugar and heading. The contents of starch went up at the prophase after treatment, then descended slightly. But it still kept on a high level. There was Iittle difference between control and treatment. When came to theratio of C/N, it was drop slightly at the prophase, and kept on a low level from then on. The change of control was similar, and there was little difference between control and treatment.5. The contents of phosphorous were improved effectively after treatment, and reduced the contents of Ca, Fe, Mn, Cu and Zn as the same. But there was little effect on K and Mg can be seen.