Abstract:In this paper, changes of endogenous ABA content in different parts of the peanut seed (Arachis hypogaea L.)development and germination in vitro were studied. The results showed that there were distinct differences in changes of endogenous ABA content among tissues of testa, cotyledon and embryonic axis in peanut seed development and germination in vitro. There existed C40 path of endogenous ABA synthesis in the testa and the cotyledon,but C15 path in the embryonic axis. During treatment of precocious maturation and precocious germination, endogenous ABA content decreased drastically in the testa, cotyledon and embryonic axis. There was a correlation between changes of endogenous ABA content and vigor index of peanut seed.