Dynamic Changes of Endogenous Hormone in Phyllagathis fordii Leaf during Flower Bud Differentiation

Changes on the hormones in the leaves of Phyllagathis fordii during its flower bud differentiation stage weremonitored. Contents of 4 endogenous hormones, i.e., IAA, GA₃, ZR and ABA, were determined by using HPLC. The results showed that, at the completion of flower bud differentiation, the contents of GA₃ and ZR peaked, while IAA reached its lowest level in the leaves. In the mid of the differentiation stage, ABA maximized while GA₃ and ZR were low. The changes on these endogenous hormones highly significantly related to the flower bud differentiation. It was found that high level of ABA/IAA, ZR/IAA, and ZR/GA₃ratios in the leaves benefited the differentiation, whereas, high ABA/GA₃favored the induction of theflower buds.