Abstract: In order to explore dormancybreaking mechanism and increase germination percentage, the effects of different temperatures of water treatments and different concentrations of IAA (indole acetic acid) on the germination process of the seeds of Angelica sinensis were studied. The results showed that soaking seeds with IAA 0.05 g·L^-1 for 3 h and soaking seeds with water 60 ℃ for 2 min had the maximum germination percentages (78% and 80%, respectively), being 1.7  and 2.5 times as high as that of the control. When soaking seeds with water 30, 35, 40, 45, 50, 55, 60, 65, 70 ℃ for 1  and 2 min, there was no significant correlation between germination percentages and temperatures, but a significant correlation was observed for 5, 10 and 15 min. There was no significant correlation between germination percentage and concentration when soaking seeds 1, 3, 6, 12 h with IAA 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 g·L^-1. Soaking seeds with water could improve seed germination percentage, which might relate to permeability of seed coat; however, IAA could improve seed germination percentage, which might be involved in breaking seed dormancy. Consequently, soaking seeds with water 60 ℃ for 2 min and soaking seeds with IAA 0.05 g·L^-1 for 3 h could improve the germination percentages of A. sinensis seeds. Compared with water, IAA pollutes the environment easily. So, soaking seeds with water is an advisable method in actual production.

Key words: photosynthesis., tomato, chlorophyll-deficient mutant, chlorophyll content