采用数量性状测量法分析了槭属(Acer Linn.)8 种1 变种1 变型的叶片形态性状差异,并采用分形方法对供试种类局部叶脉和叶片轮廓进行分维值计算;在此基础上,对供试槭属植物叶片的形态多样性进行比较,并讨论了分形理论在叶片形态特征的定量分析及植物系统学研究中的意义。叶片数量性状的测量结果表明:供试种类叶片的矩形度和叶形系数呈显著正相关,纵横轴比与一级脉角呈显著负相关,这些叶片形态参数的变异程度与叶片的形态多样性有关,虽然能在一定程度上反映槭属植物的叶形及叶脉结构变化,但难以充分反映叶片的变异细节及本质特征。分维值的计算结果表明:供试种类的叶片轮廓和局部叶脉的分维值呈显著负相关;叶片轮廓分维值在种间及种内均有显著差异(P<0. 05),但部分种类间局部叶脉分维值差异不显著(P>0. 05);鸡爪槭(A. palmatum Thunb.)的叶片轮廓和局部叶脉的分维值变异系数显著高于其他供试种类,表明其种内叶片变异的多样性相对较高。根据叶片轮廓和局部叶脉的分维值,可将供试种类分为4 类:鸡爪槭、红枫[A. palmatum f. atropurpureum (Van Houtte) Schwerim]和羽裂槭[A. palmatum var. dissectum (Thunb.) Miq.]归为一类,锐角槭(A. acutum W. P. Fang)、色木槭(A. mono Maxim.)、茶条槭(A. ginnala Maxim.)、三角槭(A. buergerianum Miq.)和中华槭(A. sinense Pax)归为一类,建始槭(A. henryi Pax)和樟叶槭(A. cinnamomifolium Hayata)各自归为一类。研究结果揭示:通过叶缘和叶脉的分形分析可以定量反映植物叶片的形态多样性,建议将叶片轮廓分维值和局部叶脉分维值分别作为种水平和属水平的分类依据;此外,分形方法也为定量化研究和评价不同叶片类型的演化程度提供了可行的途径。

Variance of leaf morphological character of species in Acer Linn. (including eight species, one variety and one form) was analyzed by quantitative trait measuring method, and fractal imensions (FD) of local vein and leaf outline of species tested were calculated by fractal method. On these bases, leaf morphological diversity of species tested in Acer was compared, and also, the significance of fractal theory in quantitative analysis on leaf morphological characteristics and in plant systematic research was discussed. Leaf quantitative trait measuring result shows that there is a significantly positive correlation between leaf squareness and leaf coefficient of species tested, and a significantly negative correlation between ratio of vertical axis to horizontal axis and the primary vein angle. Variance degree of these leaf morphological parameters relates to leaf morphological diversity, although, which can reflect change in leaf shape and leaf vein structure of species in Acer at a certain degree, but it is difficult to fully reflect the detail and substitutive characteristics of leaf variance. Calculation result of FD shows that there is a significantly negative correlation in FD between leaf outline and local vein of species tested, and FD of leaf outline has the significant difference (P<0. 05) in interspecific and intraspecific levels, but that of local vein has no significant difference (P>0. 05) among a part of species tested. Coefficient of variation of FD of leaf outline and local vein of A. palmatum Thunb. is significantly higher than that of other species tested, indicating that its interspecific diversity in leaf variation is relatively high. According to FD of leaf outline and local vein, species tested could be divided into four groups: A. palmatum, A. palmatum f. atropurpureum (Van Houtte) Schwerim and A. palmatum var. dissectum (Thunb.) Miq. Are classified a category, A. acutum W. P. Fang, A. mono Maxim., A. ginnala Maxim., A. buergerianum Miq. and A. sinense Pax are classified a category, and A. henryi Pax and A. cinnamomifolium Hayata are classified a category independently. It is concluded that fractal analysis on leaf margin and leaf vein could reflect quantitatively the leaf  morphological diversity of plant, suggesting that take FD of leaf outline and FD of local vein as taxonomic basis on the levels of species and genus, respectively. In addition, fractal method provides a feasible way for quantitatively researching and evaluating the evolution degree of different leaf types.