Abstract: Injecting IAA, GA3, and KT into soybean ( Gtycine max L. ) seeds in vivo on intact plant of 30 d after anthesis, the ABA content, invertase and ATPase activity in seed coat and cotyledons were tested respectively. It was revealed that the content of endogenous ABA was correlated with the invertase and ATPase activity. The ABA level increased was 24% and 65 % in seed coat by using 10-6 mol/L LAA and 10-6 moL/L KT and decreased 19% and 41% in cotyledons, respectively. Correlatively, ABA stimulated invert&se activity and inhibited ATPase activity in seed coat, but the reverse effect of ABA was seen in cotyledons. Treated with 10-6 mol/L GA3, ABA level droped by 42% in seed coat and by 22% in cotyledons. Activities of invertase and ATPase were inhibited in seed coat but stimulated in cotyledons. In studying the changes of sugar and protein in the cotyledons, it was shown that ABA was involved in the assimilate accumulation in soybean seeds. The effects of exogenous hormones on endogenous ABA level and ABA in relation to assimilate accumulation in the cotyledons were discussed.

Key words: Soybean, Hormones, ABA, Assimilate, Acid invertase, ATPase