乌龙茶种质叶片微形态特征的扫描电镜观察

Scanning electron microscopy observation on foliar micromorphology of Oolong tea germplasms

【目的】观察乌龙茶种质叶片的微形态性状,为探明乌龙茶品种资源微形态特征及其分类提供参考依据。【方法】利用场发射扫描电镜观察27份乌龙茶种质叶片的微形态,分析其叶片气孔、茸毛和蜡质纹饰形态特征。【结果】供试茶树种质叶片的茸毛纹饰分为长条纹型、短棒型和光滑型3种类型;叶表蜡质纹饰分为皱脊状、波浪状和平展状3种类型;气孔器较相似,均呈长卵形。通过聚类分析可将27份茶树种质分为3个分支。相同原产地种质的叶片茸毛微形态和叶表蜡质纹饰较相似。灌木型乌龙茶种质的茸毛长度显著短于小乔木型(P<0.05,下同),叶片气孔密度显著大于小乔木型,多数小乔木型乌龙茶种质的叶表纹饰呈平展状。【结论】乌龙茶种质的气孔形态特征不具有种间分类意义。茶树叶片的茸毛和蜡质纹饰可作为乌龙茶种质资源分类鉴定的手段之一。在利用叶片微形态进行茶树种质资源分类鉴定研究中,应注意树型对叶片茸毛和叶表纹饰特征的影响。

【Objective】The foliar micromorphological characters of Oolong tea germplasms were observed,which would provide reference for Oolong tea germplasms micromorphological characters and taxonomy.【Method】The foliar micromorphology of 27 Oolong tea germplasms was investigated by field emission scanning electron microscopy(FESEM),and micromorphological characters including leaf stomatal apparatus,trichome and adaxial epidermal waxy ornamentation were analyzed.【Result】Three basic trichome ornamentation types of the tested tea germplasms leaves could be identified into long-stripe type,short-rods type and smooth type.Three kinds of adaxial epidermal waxy ornamentation were ridging type,wavy type and flat type.The types of stomatal apparatus were similar,which were oval.The cluster analysis showed that the twenty-seven tea germplasms could be divided into three clusters.The trichome micromorphology and the adaxial epidermal waxy ornamentation of Oolong tea germplasms from the same geographical area showed some common characteristics.Comparing the differences between shrub and dungarunga,it was found that the trichomes of shrub Oolong tea gerplasms were significantly shorter than that of dungarunga Oolong tea gerplasms,and the stomatal density of shrub Oolong tea germplasms was significantly larger than that of shrub Oolong tea gerplasms(P<0.05,the same below).The adaxial epidermal waxy ornamentations of most dungarunga Oolong tea germplasms were flat type.【Conclusion】The stomatal micromorphology characters of the Oolong tea germplasms leaves have no taxonomic significance.The micromorphological characters of trichome and adaxial epidermal waxy ornamentation can be used as one of the methods of classification and identification of Oolong tea germplasms.In the study of the classification of tea germplasms that based on leaf micromorphology,the effects of tree shape on trichome and adaxial epidermal ornamentation should be noticed.