Dynamic changes of endogenous hormone in litchi (Litchi chinensis Sonn.) pistil and stamen during flower development

The dynamic changes of litchi pistil and stamen endogenous hormone in the process of flower sex determination were investigated. The results show that the development of pistil is related to higher concentrations of IAA and iPAs. Lower concentrations of GA and ZRs are benefit for sexual organ development while higher concentrations inhibit corresponding sexual organ development. There is relatively higher concentration of ABA in the abortive stamen or pistil. But in the aspect of hormone equilibrium, when the ratios of growth-promoting substances and inhibitory substances is relatively higher, that is, the ABA concentration of stamen is relatively lower, the stamen development is normal; contrarily, the pistil development is normal. Thus it is suggested that the regulation of sex determination of litchi flower is not the sole effect of some kind of hormone but the combined effect of all kinds of hormones' interaction in time and in space. Fig 2, Tab 2, Ref 17