6种野牡丹属植物叶片表面特征及其分类学意义研究

长期以来学术界对于中国野牡丹属植物的分类存在较大分歧,为了弄清各个种之间的关系,对野牡丹属6种植物叶片表面形态特征进行扫描电镜观察,并对叶表面形态特征进行聚类分析。结果表明,除地菍叶片上表面外,其余5种植物叶片上、下表面均有表皮毛;野牡丹和多花野牡丹下表面中脉上均有锥形和鳞片形2种形态的表皮毛,不同之处在于野牡丹为长锥形,多花野牡丹则为短锥形;细叶野牡丹和毛菍中脉上的表皮毛均为锥形,但细叶野牡丹表皮毛基部后延,毛菍则不后延;展毛野牡丹中脉上的表皮毛为长鳞片形。通过聚类分析发现细叶野牡丹、展毛野牡丹、多花野牡丹三者的亲缘关系较近,聚为一类;野牡丹、毛菍和地菍则与其亲缘关系都比较远,各自聚为一类。结合花期观察结果,推断野牡丹和多花野牡丹为2个不同种,该结果与《中国植物志》中文版基本一致,由此表明野牡丹属植物叶表面特征可为本属植物的分类与鉴别提供依据。

Leaf surface characteristics of 6 species of Melastoma L. and their taxonomic significance

It has been a debating question for quite a long time about the taxonomy of Melastoma L.plants in China.In order to make clear the relationship of Melastoma L.plants in China,scanning electron microscopy(SEM) was applied to observe the leaves of six species of Melastoma.The morphological characteristics and micro-morphological characteristics of the leaves observed under the SEM were conducted cluster analysis using SPSS.The results are as follows: except the adaxial surface of the leaves of M.dodecandrum,there are trichomes on both adaxial and abaxial surfaces of the leaves of all other plants.Both the cone-shaped and flake-shaped trichomes appear on the midribs from the abaxial surface of the leaves of M.candidum and M.affine.The trichomes on the midribs of M.intermedium and M.sanguineum are cone-shaped,of which the base of the trichomes on the former one are extended,while the latter one only enlarged,but not extended.The trichomes on the midribs of M.normale are of flake shape.The cluster analysis shows that the genetic relationship among M.intermedium,M.normale and M.affine is relatively close,while the genetic relationship among M.candidum,M.sanguineum,and M.dodecandrum is relatively far.Combined with flowering observation,it can be concluded that M.candidum and M.affine are two different species,which is consistent with the Chinese version of Flora of China.These findings indicate that the characteristics and micro-morphological characteristics of the leaves of Melastoma.can provide evidence for the classification and identification of the species under this genus.