Study on the Vessel Elements and Its Perforation Plate of Secondary Xylem in Ziziphus mauritiana

The vessel elements of secondary xylem in Ziziphus mauritiana was observed by bio-microscope image analysis system and micrography.The results show that there are various patterns of vessel elements and three types of perforation plates: both ends of the vessel element aresimple perforation plate;one end is simple perforation and the other is scalariform perforation;the simple perforation with cilia in Z.mauritiana.It is discussed that the ontogeny and phylogenesis of vessel elements in Z.mauritiana.The new evidence was provide on the phylogenesis of perforation.