Abstract: The optimum seed collecting time, the difference of seed maturity of different mother trees and growth characteristic of seedlings of Physocarpus amurensis was studied. The results showed that the optimum collecting time of seed was the end of July, and dormancy after seed mature,The statistical results showed that the germination percentage and the 1000-kernal weight were highly significant difference (p<0.01), and the germination percentage were increase by power function with the size of the 1000-seed weight, and coefficient was 75.75% (p<0.1). The seedling biomass investment to roots was highest, stems was smallest and leaves was midst; biomass investment to roots and leaves(variance coefficient were 6.8%,11.03%,respectively) was more steady than that to stems(variance coefficient was 21.81%, respectively). The diameter of the tufts was the important quantitative index to measure the special size of P. amurensis seedlings. The total biomass and the biomass of the roots, stems and leaves were all increased by linear function with the size of tuft diameters, and the correlation were all significant.

Key words: Physocarpus amurensis, sexual reproduction, seed collecting time, seed germination, seedling growth