The germination capacity of Pinus tabulaeformis seeds was obviously improved after the seeds were soaked with the different concentrations of natural brassinolide. The germination rate and germination energy of the seeds were increased by 23 1% and 14 94% respectively, and the mean germination speed ( i.e. germination time) of the seeds was cut down by 1 day under the best concentration (0 05?mg·L -1 ) treatment, compared with the control. After Robinia pseudoacacia seeds were treated with the best concentration(0 1?mg·L -1 ) of natural brassinolide, the germination rate and germination energy of the seeds were increased by 10 9% and 15 9% respectively, and the mean germination speed of the seeds was cut down by 1 26 day, compared with the control. After hypocotyls of Pinus tabulaeformis and Robinia pseudoacacia were treated with the natural brassinolide, the elongation of their hypocotyls was obviously increased. 0 01?mg·L -1 concentration of the natural brassinolide was the most suitable for the elongation of Pinus tabulaeformis hypocotyls,and 0 005?mg·L -1 concentration was the best for the elongation of Robinia pseudoacacia hypocotyls.
