Abstract: Jujube witches' broom (JWB), caused by phytoplasma, is the most serious and destructive disease of Chinese jujube (Ziziphus jujuba Mill.). In order to reveal the influence of phytoplasma on the endogenous hormone of Chinese jujube, the contents and variations of Zeatin, IAA, GA3 and ABA in healthy tree, diseased tree and the diseased jujube cured with oxytetracycline were measured around the whole year by HPLC. The result showed that in root, there were no difference in the contents of IAA, GA3 and ABA among healthy, diseased and cured jujube, but obvious difference in the content of Zeatin between diseased (high) and healthy jujube in July and August. In leaves, there were also no difference in the contents of IAA, GA3 and ABA among healthy, cured and diseased jujube, but the content of Zeatin of diseased jujube increased continuously and was higher obviously than that of healthy one in later stage. Comparison among jujube with different diseased extent showed that the heavier the diseased extent, the higher the Zeatin/IAA (C/A). All those results indicate that the infection of phytoplasma could cause the unbalance of the endogenous hormone and resulted in the witches’ broom symptom at last.

Key words: Chinese jujube, Jujube witches' broom (JWB), Endogenous hormone, Variations