Abstract: In order to reveal the habitat adaptive capacity of the invasive species Bistorta macrophylla in the process of drought in alpine meadows,we selected humid,subhumid and drought habitats in the alpine meadows of the Baima Snow Mountain in northwestern Yunnan Province to set up sampling plots and collect experimental materials. Changes in leaf anatomy and calcium oxalate content along habitat drought were investigated using one-way ANOVA and principal component analysis. The results showed that the palisade tissues were tightly arranged in 2 layers,5~9 vascular cylinder in the main veins were arranged in a ring,and the xylem was distributed towards the center of the ring. Leaf thickness,upper epidermal and stratum corneum thickness,lower epidermal thickness,palisade(P) and spongy(S) tissue thickness,main vein and vascular cylinder thickness,xylem and phloem thickness,and leaf calcium oxalate content differed significantly among habitats and had the greatest values in the drought habitats (P <0.01),with the leaf calcium oxalate content contributing the most to the drought tolerance of B. macrophylla. Lower epidermal stratum corneum thickness and P/S did not differ significantly among habitats. Under drought stress,B. macrophylla reduced water evaporation by increasing the thickness of water retaining structures (epidermis,epidermal stratum corneum),improved water transport efficiency by increasing the thickness of water transporting structures (vascular cylinder,xylem),and enhanced the water storage capacity by increasing the calcium oxalate content. Namely,the strategies of enhancing the function of water retaining and water transporting structures and increasing the coordinated response of anatomical structures and calcium oxalate content were used to resist the drought of the habitat.

Key words: Anatomical structure, Water retention structure, Water transport structure, Soil moisture gradient, Calcium oxalate content

摘要： 为揭示高寒草甸生境干旱化过程中侵入种圆穗蓼(Bistorta macrophylla)的生境适应能力，在滇西北白马雪山高寒草甸选择湿润、半湿润和干旱生境设置样方、采集实验材料。利用单因素方差分析、主成分分析等方法，分析叶片解剖结构和草酸钙含量与土壤水分之间的关系。结果表明：叶片栅栏组织紧密排列为2层，主脉中5~9个维管束呈环形排列，且木质部朝中心方向分布。叶片、上表皮及角质层、下表皮、栅栏组织与海绵组织、主脉与维管束、木质部与韧皮部等结构的厚度以及叶草酸钙含量在生境间差异显著(P＜0.01)，且干旱生境中数值最大，其中叶片草酸钙含量对植株耐旱能力贡献最大。下表皮角质层厚度、栅海比在生境间的差异不显著。圆穗蓼通过增加保水结构(表皮与角质层)厚度以减少水分蒸发，增加输水结构(维管束、木质部)厚度提高输水效率，增加草酸钙含量增强贮水能力。即采取增强保水和输水结构功能、提高解剖结构与草酸钙含量协同响应等策略抵御生境干旱化。

关键词: 解剖结构, 保水结构, 输水结构, 土壤水分梯度, 草酸钙含量