陕西小檗属14种植物叶脉序式样的研究

Leaf Venation Patterns of Fourteen Species of Berberis in Shaanxi Province

为探索叶脉序特征在小檗属植物分类上的意义,对陕西14种小檗属植物的叶脉序特征进行了比较研究。结果表明:陕西14种小檗属植物的叶脉序分为花环状半达缘脉和花环状弓形脉2种。叶脉分支一般有5级:①一级脉均为羽状脉,有粗、中等、细三种类型;②粗二级脉的分叉角变化有上端二级脉比下端尖、上端二级脉比下端钝、分叉角度几乎一致、最底端二级脉所形成的角比上端都尖4种类型,细二级脉半达缘或真曲形,间二级脉均为复合型;③三级脉贯串型或结网型;④四、五级脉共同构成网眼,网眼发育不完善,形状不规则,大小的变异幅度不一;⑤盲脉从不分支到不均等分支的各种类型都有。说明小檗属种间的叶脉序特征存在着差异,具有重要的分类和鉴定意义。基于叶脉序特征编制了陕西14种小檗属植物的分种检索表。

In order to explore the significance of leaf venation characteristics in the classification of Berberis,a comparative study of the leaf venation characteristics of 14 species of Berberis in Shaanxi province was carried out.The results showed that the leaf venation of 14 species can be divided into two types:festooned semicraspedodromous and festooned brochidodromous.The branches of leaf veins generally had five grades:i)primary veins were all pinnate veins,which had three performance:stout,moderate and weak;ii)second grade with four types of bifurcation angle changes of major secondary veins:the sharper upper secondary veins than the lower ones,the blunter upper secondary veins than the lower ones,the almost-same bifurcation angles,and the sharper angles formed by the lowest secondary veins than those of the upper ones;iii)tertiary veins crossed between adjacent secondaries,or anastomosed with secondary veins to form a net;iv)quaternary and quinternary veins formed the areole together.The areole was not well developed,and its shape was irregular;v)there were various types of veinlets from never branched to unevenly branched.The results indicated that there are differences in the venation characteristics among Berberis species,which is of great significance in classification and identification.The key to 14 species of Berberis in Shaanxi province was compiled on the base of the characteristics of leaf venation.