在苏铁类植物中再次发现导管

本研究对越南蓖齿苏铁（Cycas elonga)的根进行了观察，发现其次生木质部中具导管，导管分子横切面观为近圆形，侧壁为孔纹纹饰，具缘纹孔，端壁具一较大穿孔，为单穿孔板，两相邻导管分子在穿孔处较水平地相连接。端壁常具尾尖；每个导管分子长度较大。这是继鳞秕泽米铁中发现导管之后再次在苏铁类植物中发现导管。这对于系统与演化植物学和结构植物学方面具重大的意义。

Discovered Vessel in Cycads Again

In this study observations to the structure of root of Cycas elonga was carried out,and vessels in secondary xylem was discovered.The vessel elements were close to circular in transverse section. The lateral wall pitted thickening with bordered pit. The end wall possessed a bigger perforation, a simple perforated plate. The adjacent vessel elements joined up rather level in the place of perforation. Some end walls often attached with tail. Evry vessel element was longer. This is the second discovery of vessel in cycads after the first discovery of vessel in Zamia furfuracea . It is of much singnificance in evolutionary botany and structural botany.