Effect of Natural Brassinolide on Germination of Ailanthus altissima Seeds

The germination capacity of Ailanthus altissima seeds improved after the seeds were soaked with different concentrations of natural brassinolide (NBR). The germination rate and germination energy of the seeds increased by 17.6% and 18.8%, and the mean germination speed (i.e., germination time) of the seeds was shortened by 1.4 d under the optimal concentration (0.4 mg·L^-1) treatment, compared with the control. After hypocotyls of A. altissima were treated with NBR, the elongation of the hypocotyls increased. Among different concentrations of the NBR, 0.4 mg·L^-1 NBR appeared to be the optimal concentration for the elongation of A. altissima hypocotyls.