关键词: 核桃, 叶片结构, 隶属函数, 抗旱性

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