Endogenous Gibberellins in Bulbils of Chinese Yam during Growth and Storage

Abstract

Five gibberellins in the early-13-hydroxylation pathway (GA₅₃, GA₄₄, GA₁₉, GA₂₀ and GA₁), and six gibberellins in the non-13-hydroxylation pathway (GA₁₂, GA₁₅, GA₂₄, GA₉, GA₃₆ and GA₄), were detected in the bulbils of Chinese yam. This indicated the presence of two gibberellin biosynthetic pathways in bulbils. The total endogenous gibberellins were dramatically increased in enlarged bulbils. The endogenous level of bioactive GA₄ was always higher than that of GA₁. A rapid increase in endogenous gibberellins including bioactive GA₄ was observed during a 30-day storage period. These results show that gibberellins are closely related to bulbil enlargement and dormancy in Chinese yam plants. However, further research is needed for better understanding of the fluctuation of gibberellin levels in bulbils of Chinese yam during storage.