Indole-3-acetic acid (IAA) and abscisic acid (ABA) were quantifiedin the third unfolded leaves of soybean (Glycine max L.) subjected to heat stress.Six cultivars of the ecophenotypes of North China were used in this experiment.They were Prematurity No.17 (PM17), Mutagenic Treatment No.4 (MT4),Mutagenesis No.31 (MU31), Dark-resistant Black Soybean (DBS), ScientificBumper Harvest No.6 (SBH6) alld No.34 (SBH34). When blooming began, IAAand ABA levels in the third unfolded leaves of heat stressed plants weresig...