为了解水分胁迫对于胡杨幼苗根系发育的影响,采用单因素控制试验研究胡杨幼苗根系生长特征对土壤水分的响应。结果表明:胡杨幼苗通过增加根冠比、优先分配根系生物量适应干旱胁迫;经断续给水处理的幼苗根系生物量明显小于连续给水处理,且差异显著,说明干旱胁迫状态影响幼苗根系生物量的积累;胡杨幼苗根系表面积随着土壤含水量的减少而减小,经断续给水处理的幼苗根表面积略大于经连续给水处理的幼苗根表面积,但差异不显著;经连续给水处理的胡杨幼苗根系长度大于经断续给水处理情况,差异显著。本研究表明胡杨幼苗能通过改变根系生长特征、根系扩展方向和生物量的积累部位来适应干旱胁迫。

To determine water stress is the key factor influencing the Populus euphratica seedling growth and survival rate,and seedling response to moisture.We took Populus euphratica seeds as study material to study Populus euphratica seedling root growth characteristics for different relative water content by the soil pot method.The results showed that Populus euphratica seedling root surface area decreased with decreasing of soil moisture,and the seedling root surface area by intermittent treatment was slightly larger than the treatment given by continuous treatment when the water content was in the same conditions.The seedling root biomass by intermittent treatment was significantly less than the seedlings under continuous treatment,and the minimum root biomass occurred when soil water content was only 5%.It evidenced that the state of drought stress influences seedling root biomass accumulation.Root length of continuous water treatment was greater than the length of the intermittent treatment in the moisture gradient,but the root width to depth ratio was less than that of the seedling by intermittent treatment.The lateral branching angle of seedlings by intermittent treatment was greater than that of the continuous ones.This study verified the water stress was the key factor influencing Populus euphratica’s seedling growth.And the seedlings can change the expansion direction and the accumulation of biomass to adapt to the state of drought stress.