板栗和锥栗天然同域居群的叶表型变异研究

对分布于湖北省秭归县境内的一个由169株板栗（Castanea mollissima）和281株锥栗（C.henryi）组成的天然同域居群的20个叶表型性状的变异进行了研究。根据叶片背面和叶柄的被毛情况及叶缘形状3个定性性状,在总共450个个体中,共得到18个（4%）中间过渡类型个体。利用17个数量性状进行逐步判别分析（SDA）表明：根据定性性状得到的中间型个体中分别有7个和11个被归入板栗和锥栗;板栗和锥栗在叶形上的差异较大,有8个数量性状被选入判别方程,判别方程对板栗和锥栗的判别准确率都达93%以上,判别结果较为理想;综合20个表型性状进行主成分分析（PCA）,构建了3个主成分,主成分1和2的贡献率分别为53.5%和18.7%,累计贡献率达72.2%。前2个主成分的散布图中,有6个（1/3）中间型个体位于板栗和锥栗的重叠分布区域,可能是二者之间存在杂交的表型证据。

Study on Leaf Phenotypic Variation of a Sympatric Population of Castanea mollissima and C.henryi

The phenotypic variation among the plants of a sympatric population composed of 169 Castanea mollissima Bl.and 281 C.henryi Rehd.& Wils.in Hubei province Zigui county was investigated based on 20 leaf morphological characters.According to pubescence on the abaxial surface of the leaf and on the petiole,and leaf marginal shape,18 (4%) of the 450 sampled individuals were assigned to intermediate types between the two species.The stepwise discriminant analysis (SDA) based on 17 numerical characters indicated that 7 and 11 individuals with intermediate morphologies were classified to C.mollissima and C.henryi respectively.There were significant differences between C.mollissima and C.henryi on the leaf morphological characters,which led to a high accuracy of identification (93%).Therefore,the discriminant functions with 8 numerical characters were effective in the distinguishing of C.mollissima and C.henryi.In the principal component analysis (PCA),three principal components were constructed based on 20 characters,with the contributory ratio of the PC1 and PC2 of 53.5% and 18.7%,respectively,and the cumulative contributory ratio of 72.2%.In the scatter diagram for PC1 and PC2,6 (1/3) individuals with intermediate morphologies were located in the contact zone between C.mollissima and C.henryi,which may provide morphological evidence for hybridization between C.mollissima and C.henryi.