桃儿七传粉生物学特性及其在进化上的意义

对分布于云南中甸县不同居群的桃儿七进行了传粉生物学特性研究，结果如下：（１）首次发现其具有一种适应于自花授粉的传粉机制。即在花尚未开放或刚开放时，雌蕊呈直立状，而一旦花完全开放时，子房柄会发生弯曲，以致整个雌蕊靠向某一花药，从而使柱头与花药贴合实现传粉；当完成传粉后，雌蕊又重新直立，此时受精作用也随之完成。整个传粉、受精过程仅需４￣６ｈ。（２）其生殖节律快，有效率高。从孢子母细胞减数分裂开始到双受

THE FLORAL BIOLOGY AND ITS EVOLUTIONARY SIGNIFICANCE OF SINOPODOPHYLLUM HEXANDRUM(ROYLE) YING(BERBERIDACEAE)

The floral biology of nine populations of SinOPOdophyllum hexandrum (Royle)Ying(Berberaceae) (Ximalaya mayapple ) in Zhongdian area,Yunnan Province,has beenstudied. The results are presented as follows: (l ) It has been observed that Ximalayamayapple has a very special pollination mechanism which adapts to autogamy. When theflower is under blossom or just in blossom,the gynoecium is upright. When the flower isin full blossom,however,the gynoecium takes place a turning and makes the whole gynoecium close to a certain anther. The stigma thus contacts with the anther and pollination occurs. After pollination,the gynoecium recovers to upright. The whole pollinationprocess lasts about 4-6 hours. (2)The reproductive rhythm of the plant is quite fast,from the meiosis of spore--mother cell to the termination of double fertilization,it takesonly about 4-6 days. Fruit--bearing rate is almost 100%,seedset ratio is 97. 32 %. (3)Ximalaya mayapple has a strong differentiation within species and shows its diversity inboth morphology and ecological adaptation. The plant is,therefore,believed to be with alarge present fitness.