骆驼刺叶片和根系主要功能性状对水分胁迫的适应

植物通过改变地上和地下器官的功能性状和养分分配响应土壤水分变化。本研究以生长两年的骆驼刺(Alhagi sparsifolia)幼苗为研究对象，设置了4个水分梯度(W1：田间持水量的30%；W2：田间持水量的40%；W3：田间持水量的55%； CK：田间持水量的75%)，并分析了骆驼刺叶和根的主要功能性状的变化特征。结果表明：水分的减少显著降低了骆驼刺的叶、茎、刺、地上、地下生物量(P < 0.05)，而对根冠比的影响并不显著(P > 0.05)。骆驼刺幼苗主要通过减小叶面积、增大比叶面积、减小根体积、增加比根长的生长策略响应水分胁迫。初步说明，骆驼刺能利用自身性状间的协同或权衡作用形成不同的适应策略。在所有水分梯度下，骆驼刺将更多的养分分配在根系中，器官间养分含量呈根 > 叶 > 茎 > 刺的规律；地上与地下之间的养分比值和水分变化正相关。本研究为塔克拉玛干沙漠南缘地区荒漠植被生态恢复提供了理论依据。

Adaptation of the main functional trait of Alhagi sparsifolia leaves and roots to soil water stress

Plants respond to changes in soil moisture by changing their functional traits and nutrients distribution across above-ground and underground organs. This research monitored the changes of the main functional traits of leaves and roots of Alhagi sparsifolia under four moisture levels (W1: 30% field capacity (FC); W2: 40% FC; W3: 55% FC; CK: 75% FC). The results showed that a decrease in water significantly reduced the plant leaf, stem, thorn, aboveground and underground biomass of A. sparsifolia, but had no significant effect on the root: shoot ratio. A. sparsifolia seedlings adapted to water stress by reducing leaf area, increasing the specific leaf area, reducing root volume, and increasing specific root length. These preliminarily results suggest that different adaptive strategies can be formed using the synergistic or balance effect among the traits of A. sparsifolia. Under water stress, more nutrients absorbed by the A. sparsifolia seedlings were distributed in the root. The regular pattern of nutrients content among the organs ranked as follows: root > leaf > stem > thorn. We found a positive correlation between aboveground and underground nutrient contents under the water stress. This study provides an effective reference for vegetation ecological restoration in the south of Taklimakan.