中文摘要：

近年来, 植物根系对土壤异质性的响应和植物根系之间的相互作用一直是研究的热点。过去的研究主要是针对一年生短命植物进行的, 而且多是在人工控制的温室条件下进行的。而对于多年生植物根系对养分异质性和竞争的综合作用研究很少。该文对塔里木盆地南缘多年生植物疏叶骆驼刺（Alhagi sparsifolia）根系生长对养分异质性和竞争条件的响应途径与适应策略进行了研究, 结果表明： （1）在无竞争的条件下, 疏叶骆驼刺根系优先向空间大的地方生长, 即使另一侧有养分斑块存在,其根系也向着空间大的一侧生长; （2）在有竞争的条件下, 疏叶骆驼刺根系生长依然是优先占领空间大的一侧, 但是竞争者的存在抑制了疏叶骆驼刺的生长, 导致其枝叶生物量和根系生物量都明显减少（p 〈 0.01）, 而养分斑块的存在促进了疏叶骆驼刺根系的生长; （3）疏叶骆驼刺根系的生长不仅需要养分, 也需要足够的空间, 空间比养分更重要; （4）有竞争者存在的时候, 两株植物的根系都先长向靠近竞争者一侧的空间, 即先占据＂共有空间＂。研究结果对理解植物根系觅食行为和植物对环境的适应策略有重要意义。

英文摘要：

Aims The responses of plant roots to soil heterogeneity and the interactive effects among plant roots have been important research topics in recent years. Most studies have focused on annual plant species and conducted ex- periments in controlled greenhouse conditions. Few comprehensive studies have been carried out on the response of perennial plant roots to soil heterogeneity and competition. Our objective is to investigate the responses and adaptive strategies of root-system growth of the perennial plant Alhagi sparsifolia to nutrient heterogeneity and competition. Methods We used sheep feces as nutrient patches to form soil heterogeneity and planted A. sparsifolia in glass pools. Seedlings received one of six factorial combinations of soil heterogeneity （uniform, patch-center and patch-edge） and competition treatments （alone versus with competition）. We excavated whole plants and analyzed their root biomass, root respiration, root system architecture and other related characteristics in each treatment after 100 days. Important findings Roots of A. sparsifolia grow in the direction where soil space is abundant under no plant competition, even though nutrient patches are present on the opposite side. Roots ofA. sparsifolia also grow in the direction where soil space is abundant under plant competition, but neighboring plants limited the development of focal plants, resulting in significantly reduced root and shoot biomass （p 〈 0.01）. Nutrient patches promote the growth of plant roots. The growth of A. sparsifolia roots needs both nutrients and soil space, and space is more important than nutrients. If neighbors are present, plant roots first occupy the space where competitors exist.