海桑属(Sonneratia)植物的木材结构及其系统演化意义

研究了海桑科海桑属(Sonnerotia)6种植物的木材结构特征，并与同科的八宝树属(Duabanga)、千屈菜科的紫薇属(Lagerstroemia)植物的木材结构进行比较。结果表明：1.射线高度和射线宽度可作为卵叶海桑区别于其它种类的鉴定特征或辅助特征；2．海桑属形成一单系的类群，并与紫薇属有更近的亲缘关系，而与同科的八宝树属的亲缘关系更远；3．导管数量特征的聚类分析可以推测海桑属植物沿两支进化，一支进化为水分输导效率高的种类(即导管直径宽和输导面积大，管孔密度小，如海桑和拟海桑)，另一支进化为水分输导安全性高的种类(即导管直径窄、输导面积小，管孔密度大，如杯萼海桑、卵叶海桑、无瓣海桑、海南海桑)。

Wood Anatomy of Some Sonneratia Species inRelation to Phylogenetic Significance

Wood structure of six Sonneratia species from Mangrove Nature Reserve at Dongzhai Port, Hainan Province, was observed under LM, SEM and Laser scanning confocal microscope. Ray height and ray width can be used for diagnostic or subsidiary diagnostic features to distinguish S. ovata from other Sonneratia species.Sonneratia forms a monophyletic group which has a closer affinity to Lagerstroemia (Lythraceae) instead ofDuabanga (Sonneraceae). The result of clustering based on quantitative data of vessel elements (pores) suggests that the Sonneratia species evolved into two clades, one including S. caseoalris and S. paracaseolaris that has the wider vessel and lower pore density suggesting a high conducting efficiency, the other including S. alba, S. ovata, S. apetala and S. hainanensis that has the narrower vessel and higher pore density resulting in high conductingsafety.