部分裸子植物假种皮微形态特征及其分类学意义

应用扫描电镜对红豆杉科、三尖杉科和罗汉松科植物假种皮的微形态特征进行了研究，结果表明：可以把红豆杉科植物分为两类，即具规则型网状纹饰的红豆杉属和具无规则型网状纹饰的白豆杉属、穗花杉属和榧树属。在后三属中，穗花杉属的穗花杉和白豆杉属的纹饰特征更为相近，同属厚网脊亚型。而云南穗花杉和榧树属的特征相近，属薄网脊亚型。假种皮表面纹饰特征显示不宜将红豆杉（T．chinensis）再分为两个独立的种，认为设立红豆杉和变种南方红豆杉（T．chinensisvar.mairei）的处理方式更加合理。三尖杉科（属）蓖子三尖杉（C．oliveri）假种皮纹饰的网脊、网底分化程度、细胞大小、单位面积细胞数和本届的其它植物差异很大，为建立蓖子三尖杉组提供了进一步的佐证。假种皮的微形态特征还支持把宽叶粗榧（C.sinensisvar.latifolia）上升为种C．latifolia的观点。罗汉松科假种皮纹饰类型的观察结果表明罗汉松属和陆均松属是自然分类群。尽管罗汉松属竹相组假种皮纹饰的网脊变异范围相对较大，但是变异范围仍在属内，不支持将其独立为新科的观点。假种皮的表面纹饰特征还表明三尖杉科和红豆杉科之间的联系密切。

A STUDY ON THE ARIL MICROMORPHOLOGICAL FEATURES OF SOME GYMNOSPERMS AND ITS TAXONOMIC SIGNIFICANCE

The aril micromorphological features and its taxonomic significance of Taxaceae,Cephalotaxaceae and Podocarpaceae are studied under SEM. The results suggest thatTaxaceae can be divided into two groups: Taxus(with regular reticulation) and Pseudotaxus-Amentotaxus-Torreya (with irregular reticulation ); In the ornamentation charactersof the later group,A. argotaenia and P. chienii are similar (with thick ridge) while A.yunnanensis is much more related to Torreya (with thin ridge ). The treatment of recog-nizing Taxus chinensis var. mairei as a variety is more reasonable than that of dividing Taxus chinensis into 2 separate species.The establishment of Sect. Pectinatae is accept-able, It is supportes to recognize the variety,Cophalotaxus sinensis var. latdelia,as a sep-arate species,Cephalotaxus latifolia. Podocarpus and Dacrydium are natural taxon; Sect.Nageia should be assigned to the Podocarpus. Cephalotaxaceae is related to the Taxac-eae.