A study on floral syndrome and breeding system of Begonia fimbristipula hance in Dinghushan Mountain
Shao Ling*，Chen Xiong-wei，Liang Guang-jian  

College of Life Science, Zhaoqing University, Zhaoqing, Guangdong 526061。
^*Corresponding Author：Tel: (0758) 2716 359; E-mail: shaoling@zqu.edu.cn;

Abstract
By investigating on the specific field observation and breeding cultivation of an unique endangered plant（Begonia fimbristipula Hance）in Dinghushan Mountain, Guangdong Province, its cross-breeding index, pollen index and stigma fertilizing ability, the ratio of pollen and ovule, artificial pollination and bagging experiments were performed for understanding the flower feature, blossom dynamic and breeding system, in order to fully master its biological characteristics and provide the basic information on the species protection and nursing strategies. Results showed: The single plant florescence of B. fimbristipula is 25-30 d, while group plants florescence last to 45-55 d. The flowers are monoecious setting on a trigeminal-like, divergence cyme. Male and female flowers mature at different time, the stamens mature earlier than pistils, and the distance between anther and stigma is 2.09±0.43 cm. The blooming pattern follows male-female-male; female flowers lag 2-3 days than male ones. The cross-breeding index (OCI) is 4 or 5, Pollen-ovule ratio (P/O) is 96. Taking the results of the bagging and artificial pollination experiment together, it indicates that B.fimbristipula flower is a mixed-crossing system using self-compatibility as the main breeding form. The specific dependence on its living environment and the long term of small gregarious self-compatibility might be one of the reasons causing this species in endangered; "bulb" is an effective compensation for its reproduction.

Key words: Begonia fimbristipula Hance; floral syndrome; breeding system; crossing-breeding index; self-compatibility