关键词: 龙眼, KClO3, 成花诱导, 激素

Abstract: Dimocrupus longan Lour.‘Fenglisui’（mid season cultivar）was employed as material for application of KClO3 with girding and bending branch to induce off-season flowering. The dynamic changes of endogenous hormones and relationship between these changes and flowering status were investigated during floral bud differentiation. Auxin（IAA）contents in apical bud decreased while IAA contents in leaf increased in response to potassium chlorate treatment. IAA contents in apical bud with potassium chlorate treatment and branch bending treatment，possess the highest flowering rate treatment，were the lowest. This result indicated that low level of IAA in the apical bud was essential for longan flowering and that the application of potassium chlorate resulted in a decrease in IAA and thus promoted the flowering. Similar to the effects of potassium chlorate on IAA，gibberellins（GA3）and abscisic acid（ABA）content in the apical bud decreased in response to potassium chlorate application. This result suggested that consistent with IAA，low levels of GA and ABA in apical bud facilitated longan flowering. In contrast，zeatin（ZT）content in the flower bud of longan with potassium chlorate treatment increased during floral induction phase，but reduced in leaves. This indicated that the increase of ZT content in the terminal buds may be major factors or signal substance in off-season flower of longan. However，flowering rate in longan with three treatments and ZT content has not been positively correlated，suggested that cytokinins promoted flowering that depends on its optimum concentration or level.

Key words: longan, potassium chlorate, floral induction, hormone