Abstract:In this paper, endogenous ABA content, growth, Precocious germination, storage protein accumulation of peanut (Arachis hypogaea L. cv. Yueyou-116) embryo in vitro wereexamined. Four treatments in the experiment were given as follows: (A)embryo with seed coat +8% mannitol; (B) embryo with seed coat+no mannitol; (C) embryo withoutseed coat + 8% mannitol; (D) embryo without seed coat + no mannitol. The resultsshowed that the embryo of peanut could normally develop without exogenous hormones.The osmotic regulator such as mannitol inhibited precocious germination, maintained embryonic development and promoted the synthesis and accumulation of storage protein. Endogenous ABA content rose in the treatment with mannitol in vitro. The regulatory effectof mannitol on the development of embryo in vitro was probably related to the incerase ofendogenous ABA content in embryo tissues.