鹅观草属一些种种子胚乳细胞的特征及其分类学意义的探讨

Characters of endosperm cells in the seeds of some species of Roegneria and their taxonomic significance

解剖观察了鹅观草属 1 8个种的胚乳细胞 ,发现这类细胞在鹅观草属各类群间的发育是不同步的 ,其中胚乳细胞的大小、形状、数量以及反映丰厚程度的长宽比不仅具有类群鉴分的价值 ,而且还可作为推证类群演化关系的旁证。分析结果表明 ,胚乳细胞体积的增大、数量的增多、细胞的变圆、长宽比值的减少皆与类群的进化趋势相顺应。据此 ,进一步阐述了鹅观草属组、系、种的系统发育关系。

The endosperm cells of 18 species of Roegneria are surveyed in the present paper.It has been found that the phylogenetic development of these cells are inconsistent among the taxa of the genus;in these inconsistent characters,the sizes,forms and quantity of endosperm cells,as well as their ratio of the length to the breadth,not only possess the value in distinguishing taxa,but also may be regarded as a collateral evidence for inferring the relationships of taxa.The results of analysis show that the enlargement of volume,increase in quantity,conglobation of form and decrease of ratio of the length to the breadth of endosperm cells are in agreement with the evolutionary trends of taxa.On these grounds,the phylogenesis among the sections,series or species of Roegneria are further expounded.