中国伞形科柴胡属果实结构的系统学价值

摘要

本文首次深入研究了中国柴胡属29种，5变种及2变形果实的三维结构。结构显示果实结构变化较大，分果表面平滑，横切面近圆形，脊略微突出。中果皮有两种分泌结构，伴生油管及非伴生油管（油管）。前者仅存在于少数物种，且直径小，后者包括不分支及分支油管。不分支油管存在于多数物种的沟（1～5）和结合面（2～7），油管通常与分果近等长，但亦存在短油管。少数物种的油管呈分支状，在中果皮不规则分布。种皮由1或2层薄壁细胞构成。胚乳在结合面平直或微凹。中果皮无结晶。心皮柄多为2个，在结合面彼此相对。柴胡属果实的多数特征存在于芹亚科其他类群，但分支状油管及2层细胞的种皮仅见于牵环花亚科，变豆菜亚科及芹亚科的基础类群。柴胡属果实的解剖结构支持分子系统学将柴胡属位于芹亚科其他类群的基础位置。%The three-dimensional structure of fruits of 29 species,5 varieties and 2 forms in the genus Bupleu-rum,from China were studied in depth and are reported for the first time in this paper.The fruit structures were found to vary greatly.The mericarp surfaces are smooth,approximately circular in transverse section, and ribs are slightly prominent.Two types of secretory structures,rib ducts and vittae,occur in the meso-carps.The former which are small in diameter are found in a few taxa and the latter include unbranched and branched vittae.The vittae occur in the furrow (1-5)and commissure (2-7)in most taxa,and they are simi-lar to mericarps in length,usually unbranched,and sometimes short.The vittae are branched in a few taxa and dispersed in the mesocarps.The testa is composed of one or two layers of parenchyma cells.The endosperm is flat or slightly concave on the commissural side.Crystals are not present in the mesocarp.There are usually two carpophores,which are arranged on opposite sides of the commissural plane.Most features of the genus are present in other groups of the Apioideae,but branching vittae and testa with two layers of cells are only found in the Azorelloideae,Saniculoideae,and some groups of the Apioideae.The anatomical structures of Bupleurum fruits support its continued classification in the Apioideae,as shown by molecular studies.