滇重楼种子休眠机理研究

【研究目的】探讨滇重楼种子休眠机理,为打破种子休眠促进滇重楼实生育苗提供理论基础。【方法】采用重量法、胚率测定、ELISA等方法对种子吸水特性、萌发抑制物及种胚休眠与发育的内源机理进行了研究。【结果】种子不存在吸水障碍,与休眠无关;滇重楼种子中存在着萌发抑制物;滇重楼种子休眠属于形态学-生理学休眠类型;内源激素ABA和GA3在滇重楼种子休眠与萌发过程中起着重要作用,ABA是引起休眠的关键因素,ABA含量的降低是滇重楼种胚发育的始动因子,GA3有助于种子的生理后熟。【结论】滇重楼种胚发育不完全、种子中存在萌发抑制物质是种子休眠的主要原因。萌发抑制物的存在可能抑制了种胚发育,而与生理学后熟过程无关。在自然条件下,滇重楼生境中较长的低温时期可能是滇重楼种子具有较长时间休眠的外界原因。

Study on seed dormancy mechanism of Paris polyphylla var. yunnanensis

Objective] In order to break dormancy of Paris polyphylla var.yunnanensis seed,the underlying mechanism of seed dormancy of P.polyphylla var.yunnanensis is necessary.Method] In this study,water absorption characters,germination inhibitor and endogenous mechanism during its dormancy and after-ripening process were observed.Results] As the seed absorbed water easily,it would not induce seed dormancy.Germination inhibitor existed in the seed.Seed dormancy of P.polyphylla var.yunnanensis was belonging to morphysiological dormancy type.Endogenous hormone ABA and GA3 played an important role in seed dormancy and germination.ABA was the key factor for seeds germination,the reduction of ABA was the initiatory factor for embryo development,while the increased GA3 benefited physiological after-ripening.Conclusion]The incomplete development of embryos and germination inhibitor was the main reason for seed dormancy.Germination inhibitor may inhibit seed embryonic development;it would not relate to physiological after-ripening.In nature,the long period of low-temperature in habitat was the environmental factor for long time seed dormancy of P.polyphylla var.yunnanensis.