Effects of Plant Growth Regulator on Endogenous Hormone Levels during the Period of the Red Globe Growth

Objective. The present study was aimed to elucidate the dynamic changes of endogenous hormone levels during the fruit growth and the changing regulation of endogenous hormone levels between normal and abnormal fruits. Methods. After using exogenous GA3 and GA3+6-BA, endogenous hormone levels such as indoleacetic acid(IAA), cytokinin(ZR), abscisic acid(ABA) and gibberellin(GA3) in normal fruits and rigid abnormal ones were determined by enzyme-linked immunosorbent assays(ELISA), respectively. Results. The results indicated that the treatments of 20mg/kg GA3 and the combination of 20mg/kg GA3+10 mg/kg 6-BA had no remarkable effects on increasing average weight of berries where the vertical diameter of grape fruits was longer than the transverse diameter. Exogenous hormone GA3 and GA3+6-BA mixture also affected the endogenous hormone levels. The content of IAA, ABA and ZR was lower in the rigid abnormal fruits than that in the normal ones, respectively, and those levels during the rapid growth period were nearly in accordance with those during the slow growth period. Conclusion. The fruit growth was closely related to the endogenous hormone levels.