在塔克拉玛干沙漠腹地，采用分层分段挖掘法对不同灌溉量条件下(每株每次灌水3 5、24.5和14 kg)梭梭(Haloxylon ammodendron)幼苗根系的分布特征进行了研究。结 果表明： 1）随着灌溉量的减少，梭梭幼苗根系生物量的分布格局有向深层发展的趋势，在不同灌溉量条件下地下垂直各层生物量与土壤垂直深度呈显著的负对数关系；2）各灌溉量梭梭幼苗的最大水平根长为垂直根长的2倍，但不同灌溉量根系生物量的水平分布趋势一致 ；3）吸收根生物量的垂直分布与土壤含水量的垂直变化基本一致，均呈“单峰型”曲线， 但灌溉量不同，吸收根生物量峰值在土壤中出现的位置也不同，随着灌溉量的减少，吸收根集中分布区有向深层发展的趋势；4）根长、根表面积和根体积随着土壤深度的增加均呈“单峰型”曲线，灌溉量愈小，根长、根表面积和根体积的峰值愈位于土壤的深层；5）根冠比和垂直根深与株高之比随着灌溉量的减少而呈增加的趋势。
Aims As a primary limiting factor affecting survival and growth of plants, moisture has important effects on above-and below-ground morphological characteristics. We studied root distribution characteristics in the Tarim Desert Highway Protection Forest to provide suggestions for water management.
Methods We excavated soil to study root distribution in Haloxylon ammodendron seedlings grown with different amounts of irrigation (35, 24.5 and 14 kg•ind. plan-1•once-1) in the Taklimakan Desert.
Important findings With less irrigation, the distribution of root biomass shifted to greater depth. Underground biomass had a significantly negative logarithmic relationship with soil depth under different irrigation amounts. Maximum horizontal spread of roots was twice that of vertical root spread, and horizontal distribution of root biomass was consistent under all irrigation amounts. The vertical distribution of absorptive roots was nearly consistent with vertical changes of soil moisture; all had a unimodal curve, but peak values of absorptive roots biomass were in different soil layers with different irrigation amounts. With smaller amounts of irrigation, absorptive roots were concentrated in deeper soil layers. Root length, root surface area and root volume all exhibited a unimodal curve under different irrigation amounts; the less irrigation, the deeper the peak values. Root-shoot ratios and proportion of vertical root depth and plant height increased as irrigation amounts decreased.