Abstract: The leaf structure(19 indexes included leaf thickness,the upper epidermis thickness and the lower epidermis thickness,palisade tissue thickness,spongy tissue thickness,main vein thickness,vascular bundle thickness,phloem thickness,stomatal size,stomata density,and so on) of 5 walnut varieties[Black walnut(Juglans regia),Qingxiang(J.regia),Liaoning 1(J.regia),Bread crossing walnut(J.major×J.regia),YZ2 (J.regia)] were studied by paraffin sectioning and glue imprinting. Based on principal component analysis to screen drought indexes, drought resistance of different walnut varieties was evaluated, which would provide a theoretical basis for drought-resistant breeding of varieties and rootstock.The results showed that there were some differences among the indexes except for the upper epidermis thickness in different walnut varieties,and the coefficient of variation was between 9.07% and 48.10%.The leaf thickness, palisade tissue thickness, sponge tissue thickness, main vein thickness,vascular bundle thickness and xylem thickness of Black walnut and Breedcrossing walnut were significantly shorter than those of Qingxiang cultivars;Leaves thickness and palisade tissue thickness of Liaoning 1 were significantly larger than those of the other two Black walnut cultivars;Vein thickness,vascular bundle thickness and stoma density of Qingxiang were significantly larger than those of the other varieties.Based on principal component analysis, leaf thickness, vascular bundle thickness, stomatal length,the lower phloem thickness and the lower parenchyma thickness were screened as indexes for comprehensive evaluation of drought resistance. Drought resistance of five walnut varieties was evaluated by membership function analysis.The order of drought resistance was: Black walnut> Qingxiang>Liaoning1>Breed-crossing walnut>YZ2.

Key words: Walnut, Leaf structure, Membership function, Drought resistance

摘要： 采用石蜡制片法和胶水印记法，对5种不同品种核桃、黑核桃、清香、辽宁1号、杂交黑核桃、实生优株2叶片结构（叶片厚度、上下表皮厚度、栅栏组织厚度、海绵组织厚度、主叶脉厚度、维管束厚度、韧皮部厚度、气孔大小及密度等19项指标）进行分析，并结合主成分分析法筛选抗旱指标，对不同品种核桃进行抗旱性评价，旨在为抗旱品种及砧木选育提供理论依据。结果表明，不同品种核桃叶片除上表皮厚度外，其他各指标均存在一定差异，变异系数在9.07%~48.10%。黑核桃和杂交黑核桃叶片厚度、栅栏组织厚度、海绵组织厚度、主叶脉厚度、维管束厚度、木质部厚度等均显著小于其他3种普通核桃品种；3种普通核桃品种中辽宁1号叶片厚度和栅栏组织厚度显著大于其他2种品种；清香核桃叶片主叶脉厚度、维管束厚度、气孔密度显著大于其他核桃。根据主成分分析，筛选出叶片厚度、维管束厚度、气孔长度、下韧皮部厚度、下薄壁组织厚度作为抗旱性综合评价的指标。利用隶属函数法对试材进行抗旱性分析，5种核桃品种的抗旱性依次为：黑核桃＞清香＞辽宁1号＞杂交黑核桃＞实生优株2。

关键词: 核桃, 叶片结构, 隶属函数, 抗旱性