摘要:
利用扫描电镜对35种1变种柃属(Eurya)植物种子的微形态特征进行了研究,并采用相对大小(长×宽)RS值和种皮表面纹饰作为种子形态比较的特征参数。结果显示,柃属种子根据相对大小RS值可划分为小型(RS<1.0),中型(1.03.0)三个等级,最小的种子相对大小不足0.5,最大的种子相对大小超过10;种皮表面纹饰分为负网纹和网纹两种类型,网纹类型在网眼的方向性、网眼形状、网眼深度、网脊特点等方面呈现出种间多样性,可用于类群的比较和鉴别。文中同时还探讨了种子大小及种皮微形态在属内的系统发育关系,推测了种皮表面纹饰的演化路线,研究结果表明种子的微形态特征对本属植物系统分类及进化研究具有重要意义,可为属内一些关键种系统位置的分析提供重要佐证。
Abstract:
The seed micromorphology of 36 taxa (including 35 species and one variety) from Eurya was investigated using scanning electron microscopy (SEM).Micromorphological cha-racters, including seed relative size (length譿idth, RS) and ornamentation of the seed-coat were investigated.Three seed sizes were recognized: (i) mini type (RS<1.0), (ii) middle type (1.03.0).The relative sizes of the smallest seeds were less than 0.5 mm2 and the largest seeds were more than 10 mm2.Two types of ornamentation of the seed-coat were described: (i) reticulate grain and (ii) negative net grain.The orientation, shape and depth of lumina, and the characters of muri varied among different species, which could be used to identify species.The systematic and phylogenetic implications of seed size and seed-coat micromorphology in the genus Eurya are discussed based on our results.The evolutionary route of seed-coat ornamentation is also conjectured.Our study showed that seed micromorphological characters provided useful data for studying the evolution of Eurya and formulating the phylogenetic positions of several key species in this genus.