Morphology of seed germination and parasitism in Cistanche tubulosa

Objective: To understand the process of Cistanche tubulosa. Method: The process of seed germination and parasitism was observed using stereomicroscope. Result: Seedling of C. tubulosa sprouted after forty day without host root's contact in fields, a tube-like-organ formed and grew auger-type from host root, the tuber apex where touches host root swelled and formed haustorium. Haustorium intruded host root epidermis and vascular bundles, and released brown substances. Then, embryo bud with six or more young leaves formed, finally the swelled tuber-like-organ broken and seed coat shed. Due to the parasitism of C. tubulosa, the host root near stem site swelled, but the other part, shrunk and disappeared gradually. Conclusion: Seed of C. tubulosa could germinate independently in fields. Tuber-like-organ formatin, haustorium formation and bud formation are key steps of C. tubulosa seedling development.