管花肉苁蓉幼苗发育解剖学研究

采用光学显微镜和透射电镜方法,研究管花肉苁蓉吸器侵入寄主根和幼苗分化建成过程的形态学。结果表明:1)管花肉苁蓉吸器接触柽柳根表皮层后,吸器顶端分化出侵入细胞。在侵入细胞引领下,吸器呈楔形结构依次侵入柽柳根皮层、中柱和木质部。在吸器侵入寄主根过程中,与寄主根皮层细胞接触的吸器细胞壁呈现增厚反应,与吸器顶端邻近的多层寄主皮层细胞被机械挤压而变形,乃至被破坏。2)在吸器侵入木质部后,与寄主根表皮连接的管花肉苁蓉芽端薄壁组织恢复分生能力,分化出芽端生长点;生长点分化鳞叶原基,鳞叶原基长大为鳞叶幼叶,在鳞叶幼叶的叶腋内分化出生长点,发育成肉苁蓉幼苗。结果显示,管花肉苁蓉吸器侵入寄主根是一个主动过程,并有机械力的参与。吸器侵入寄主根和芽端生长分别呈现单极生长方式。

Developmental and anatomical studies on Cistanche tubulosa seedling

The penetration of the haustorium and seedlings differentiation of Cistanche tubulosa were studied using light and transmission electron microscopy.It was shown that:(1)The invading cells formed after the haustorium connected with epidermis of host root.Then,the wedge-shaped haustorium penetrated the host cortex,column and xylem.During penetration of the host cortex,the cell walls of the haustorium at the host-parasite interface were thicker than those of the host cells and other haustorium cells.The structure of the host cortical cells were mechanically crushed and deformed or even destroyed.(2) After the haustorium connected to the host vascular system,the germ tube cells which connected with the host epidermis were self-differentiated into meristem,then the meristem developed into growth point of Cistanche tubulosa bud.Then scale leaf primordial developed.The results showed that the invasion of C.tubulosa haustorium was an active process and the mechanical force was involved.Haustorium invade host roots and its growing of shoots are showing unipolar growth mode.