鹅掌楸属(木兰科)次生木质部导管穿孔板的比较研究

利用扫描电子显微镜对鹅掌楸属仅存的2个自然种鹅掌楸和北美鹅掌楸的次生木质部导管穿孔板特征进行了详细的研究。结果显示,鹅掌楸属的2个种均以梯状穿孔板为主,同时存在网状-梯状混合穿孔板。鹅掌楸和北美鹅掌楸的导管穿孔板具有明显差异:(1)鹅掌楸具网状穿孔板,而北美鹅掌楸没有观察到;(2)北美鹅掌楸具单穿孔板,而鹅掌楸在该实验中未发现;(3)北美鹅掌楸具有横隔较粗的梯状穿孔板且横隔数目较多;(4)鹅掌楸的导管穿孔板多数横隔较少;(5)北美鹅掌楸的穿孔板倾斜角度较大;(6)北美鹅掌楸具麻黄式穿孔板的存在,且有纹孔膜残留存在。研究认为,北美鹅掌楸导管分子穿孔板分化较鹅掌楸更为剧烈。

Comparative Investigation of Vessel Elements in the Secondary Xylem of Liriodendron

The perforation plates of vessel elements in secondary xylem of Liriodendron which include 2 species were observed in detail by scanning electron microscope (SEM), and many details were observed that were not reported by light microscope. Reticulate scalariform perforation plates exist in Liriodendron, and the simple perforation plate, epledroidforation and pit membrane remnants were observed in L. tulipifera. The results showed: (1) for Liriodendron chinense (Hemsl.) Sarg., the perforation plates are typically scalariform with a few bars and reticulate scalariform perforation plates, but occasionally are reticulate perforation plate; (2) for Liriodendron tulipifera, the perforation plates are scalariform perforation plates and reticulate scalariform perforation plates, but occasionally are simple perforation plates; (3) part of scalariform perforation plates in L. tulipifera with wider and more bars; (4) perforation plates with a few bars are more in L. chinense than in L. tulipifera; (5) the perforated plates in L. tulipifera are more inclined than in L. chinense; (6) epledroidforation and pit membrane remnants were observed in L. tulipifera. The conclusion is that the perforation differentiation of L. tulipifera is more violent.