中文摘要：

从区域尺度着手，沿塔里木河流域分别从上游、中游和下游选择气候和土壤条件有差异的阿拉尔、轮台县和尉犁县分布的天然胡杨林为研究区，在每个研究区内，选择8个大小相等的50m×50m样方，在样方内随机选择成年胡杨植株3株，并取其叶片作为研究对象，采用常规石蜡切片法，对3个不同区域分布的胡杨叶片解剖结构特征进行比较观察和研究，探讨胡杨为适应不同分布区环境条件所表现出的解剖学特征及适应策略差异。结果表明：（1）3个研究区分布的胡杨在叶片基本解剖结构特征上相一致，表现为：a．上下表皮均为由双层细胞所构成的复表皮；b．叶肉在接近上下表皮处均分化有栅栏组织，属于等面叶，同时叶肉组织中均可见染色相对较深的粘液细胞；c．叶脉维管束外均可见呈“帽”状包围的厚壁细胞，类似禾本科植物的“维管束鞘”。（2）从整个塔里木河流域来看，叶片各解剖结构指标变异程度不同：变异系数大小范围为0．029—1．786，且上表皮细胞厚度变异系数最小，叶片厚度的变异系数最大。（3）叶片解剖结构指标的量化值在不同地区间存在一定差异：叶片厚度、栅栏组织厚度、角质层厚度、下皮层厚度和栅／海等指标均表现为尉犁县〉轮台〉阿拉尔，表明胡杨以增加叶片厚度、角质层厚度、表皮细胞厚度等方式来储藏水分和减少水分散失，以适应较为干旱的环境。（4）各结构指标多与海拔、经纬度间存在显著相关性：上表皮厚度和上角质层厚度分别与经度呈显著（P〈0．05）和极显著（P〈0．01）正相关；叶片厚度、叶肉厚度、栅栏组织厚度和栅／海均与经度呈极显著（P〈0.01）负相关；上表皮厚度、上角质层厚度及栅／海与海拔高度呈显著（P〈0．05）或极显著（P〈0．01）负相关。

英文摘要：

From the regional scale, three natural ranges of Populus euphratica in Alar, Luntai and Yuli County with different climate and soil conditions were chosen from the upper, middle and lower reaches of Tarim River Basin, respectively. In each site, 8 plots with the same size of 50 m ×50 m were chosen and within each plot, leaves from 3 adult trees of P. euphratica were selected randomly. Routine paraffin sectioning method was used to observe and compare the leaf anatomical characters of P. euphratica, and explore their adaptive strategies and anatomical features to adapt to different environmental conditions. The results showed： （1）The basic leaf anatomical characters from 3 distribution areas were consistent with each other, and showed： a. The upper and lower epidermis were both mutiple epidermis and consisted of double layer of cells; b. Palisade tissue of mesophyll was differentiated close to upper and lower epidermis, and the leaf belonged to isolateral leaf. The mucous cells which relatively deep stained were also visible in the mesophyll tissue, c. The ＂bundle sheath＂ consisting of thick-walled cells was visible outside the vein vascular bundle. （2） From the whole point of the Tarim River Basin, there were vary degrees of variations among the leaf anatomical structure indexes. The range of variation coefficient was from 0. 029 to 1. 786, and the thickness variation coefficient of upper epidermal cells was smallest, while the blade thickness was largest. （ 3 ） The quantitative values of leaf anatomical structure index varied in different areas： leaf thickness, palisade tissue thickness, cuticle layer thickness, lower epidermis thickness and the grid/sea showed Yuli County 〉 Luntai County 〉 Alar County, which indicated that P. euphratica stored water and reduced water loss to adapt to the relatively dry environment through increasing the thickness of leaf, cuticle layer and epidermal cells. （4） There was significant correlation between the structure indexes and altitude, latitude a