Morphological Development of Parasitic Growth in Cistanche deserticola
肉苁蓉寄生生长形态发育

Cistanche deserticola, a kind of root parasitic psammophyte, is an endangered rare Chinese traditional medicine plant. We performed artificial culture and induction of C. deserticola to study seed germination, haustorium generation and morphologic development by optical microscopy and scanning electronmic roscopy. The results showed the following: (1) Artificial culture could produce seed germination, and embryo of C. deserticola showed polarity, with the micropyle cells being smaller than the chalazal ends and differentiated into white radicle-like organs.(2) The primary haustorium can be induced by some chemicals. After culture in 2,6-dimethoxyl pbenzoquinone for 24-26 h, the anterior part extended, formed the protuberance, then transformed into a root hair-like structure called primary haustorium.(3) C. deserticola is an active parasitic plant, and secondary haustorium or iginated after adhesion between the primary haustorium and young roots of the host. Co-culture with Haloxylon ammodendron, the primary haustorium conglutinate with young roots of the host (0.1 mm), pass through the host's epidermis and cortex , then connect with the vascular bundle and transform into secondary haustorium, shaped by fundamental tissues of differentiation and development. The development of horizontal growth of the parasitized host was quickened, and the same time, C. deserticola began to differentiate and develop. (4) C. deserticola can be a parasite anywhere in young roots (0.1 mm) of a host.