锁阳和肉苁蓉寄生方式的区别

锁阳和肉苁蓉都是中医药里重要的补益类药材，但由于过度采挖和采挖方式不当，目前它们的野生资源已濒临枯竭。肉苁蓉和锁阳分别是我国濒危和易危珍稀植物，研究二者寄生方式的特点与区别不仅可以促进锁阳和肉苁蓉的人工栽培，从而使野生药材得到一定的保护，而且对了解寄生植物在荒漠地区等极端严酷环境中的适应机制具有重要的生态学意义。该研究采用形态学观察结合常规石蜡切片法，对锁阳和肉苁蓉分别在各自寄主植物上的寄生方式进行了研究。结果表明：(1)锁阳的营养繁殖体在寄主植物根部呈串状分布，与寄主植物的连接方式属于非末端寄生；锁阳的吸器侵入寄主根系韧皮部和木质部的一部分区域，但是韧皮部和木质部大部分区域未被锁阳吸器占据，即有部分营养物质被锁阳“截取”。(2)肉苁蓉在其肉质茎基部长出新的芽体，与寄主植物的连接方式属于末端寄生；肉苁蓉的吸器侵入寄主根韧皮部和木质部全部区域。因此，锁阳寄生后，被寄生的寄主根依然能够向前生长，具有正常的功能；肉苁蓉寄生后，寄生点的寄主根失去根系的正常功能，成为一个为肉苁蓉生长发育提供营养物质的“输送通道( Transport channel)”。

Difference of parasitic form of Cynomorium songaricum and Cistanche deserticola

Cistanche deserticola and Cynomorium songaricum are important tonic herbs of traditional Chinese medicine, but currently their wild resource is in danger of drying up in China because of excavation excessively or incorrectly meth-od. Cistanche deserticola is the endangered plant and Cynomorium songaricum is a rare vulnerable plant of extinction in China. The study on the parasitic forms and characters of them can promote the cultivation of them, at the same time, protect the wild medicinal herbs resource, and it has the important ecological significance on the adapted mechanism of parasitic plants to desert environment. We compared the parasitic forms of C. songaricum and Cistanche deserticola in their host plants respectively through morphology observation and routine paraffin section. The results were as follow:( 1) The vegetative propagation buds of Cynomorium songaricum grew on the root of host plant one by one and the para-sitic form was Non-End parasitic. The haustorium of C. songaricum invaded into phloem and partial part of xylem of host plant , but most areas of phloem and xylem were not been occupied by haustoria, namely some nutrients of host were“in-terception” by C. songaricum on the process of transportation. ( 2) Cistanche deserticola grew new buds in the base of fleshy stem, the parasitic form was End parasitic. The haustorium of C. deserticola invaded into all the xylem and phloem of host plant. After been parasitized by Cynomorium songaricum, the root of its host plant could grow continuely and have the regularly function. After been parasitized by Cistanche deserticola, the root of host plant losed normally function, and became a“Transport channel” to supply nutrition for C. deserticola.