Poplars are the wide spread species as well as among the fast growing trees on the earth. Because of our country large-scale territory, belongs to kinds of the climate and soil styles, so the poplar exceedingly rich. The researches on Poplar will have the significance of environment and economic value. In this paper, the extraction technology of the phenols from leaves of Populus Canadensis Moench., and the method for determination of IAA and GA3 in the male floral buds of Populus tomentosa Carr.were studie...