Studies On The Breeding System Of Miscanthus Sinensis

Miscanthus sinensis, the Grass and Miscanthus Anderss, is a perennial tall grass of C4-plant. Internationally, Miscanthus Anderss is considered one of the most potential plant of energy crops. China is the distribution center of the world's resources of Miscanthus Anderss. In our country there are 6 species of Miscanthus Anderss. Chinese scholars' studies show that Miscanthus Anderss is a type of plant resources with ecological and economic benefits. At present, the study on reproductive biology of Miscanthus Anderss is rarely reported. The study of the reproductive characteristics of Miscanthus sinensis is inadequate. Reproductive characteristics of Miscanthus sinensis was studied in this article, including flowering phenology, breeding system, meiosis of pollen mother cell, pollen viability, stigma viability and growth of pollen tube at the stigma. The major results were as follows:(1) Flowering period of Miscanthus sinensis was short and centralized, and it persisted approximately 7 days. The blooming time of single flowers concentrated on 6-8a.m. daily.The flowers of Miscanthus sinensis were hermaphrodite flowers. The inflorescence was conical. After a single flower bloomed, the stigma were exposed outside all the time, and the Stigma could accept the pollen continuously. Time sequences of appearance of stamens and pistil during single flower opening showed that the flowers of Miscanthus sinensis didn't has time limit of pollination. Spatial distances among anthers ovary and stigma of the single flower showed that the flowers of Miscanthus sinensis didn't has space limit of pollination. Floral features of Miscanthus sinensis assured pollination success and the pollen shortage limiting burliness never happened.(2) The pollen/ovule ratio of Miscanthus sinensis was 7341±732. The result showed that Miscanthus sinensis was a kind of outcrossing plants. The result of experimentation of bagged also showed that it was a highly self-sterile plant.(3) In nature, most of Miscanthus sinensis was diploid. Meiosis of pollen mother cell was studied, and the result showed that meiosis of pollen mother cell was normal. So it had no impact on sexual reproduction.(4) Pollen viability and stigma receptivity were important factors of pollination process. The results showed that pollen viability and stigma receptivity of Miscanthus sinensis persisted 90min and 4-5 days respectively. So the pollen viability of Miscanthus sinensis limited the time and distance of pollination. But the stigma receptivity of Miscanthus sinensis could alleviate the pressures to assure pollination success.(5) Fluoroscope observation of the compatible and incompatible pollination in M. sinensis showed that growth of selfing pollen tubes were restrained on stigmas. Selfing pollen tubes stopped when they just entered into the stigma in a short distance. Incompatible pollen tubes presented a series of abnormal phenomenon, such as the top of pollen tubes getting passivated, callose depositing irregularly and callose depositing on the top of pollen tubes. The result explained self-sterile of Miscanthus sinensis, and the mechanism need further study.