濒危植物夏蜡梅花部综合特征与繁育系统

Floral syndrome and breeding system of endangered plant sinocalycanthus chinensis

野外定点观察夏蜡梅(Sinocalycanthus chinensis)的开花进程和花朵的功能形态特征,运用杂交指数、花粉-胚珠比、人工授粉和套袋试验等方法测定夏蜡梅的繁育系统.结果显示:夏蜡梅花各部形态和数量存在普遍的变异.单花花期为7～9d,开花进程中,雄蕊向心聚合,最后包围雌蕊,柱头与花药基本等高.夏蜡梅花雌雄异熟,雌蕊先熟,雌雄蕊无明显异位.单花花期依其形态和雌雄性功能表达可分为6个时期:蕾期、开花前期、雌性期、两性期、雄性期和谢花期.夏蜡梅杂交指数为3,花粉-胚珠比为29571±5839.授粉实验结果显示其不存在无融合生殖,为自交亲和,虫媒在传粉过程中起了较大的作用,表明夏蜡梅的繁育系统以异交为主,但自交亲和,为混合交配系统.

Sinocalycanthus ehinensis is a rare and endangered deciduous shrub endemic to Zhejiang, China. In order to understand the reproductive biology of S. chinensis and its possible effects to its status of being endangered, the floral syndrome and breeding system were investigated. A field investigation of the flowering course and functional floral morphology of Sinocal.ycanthus chinensis was conducted. Outerossing index and pollen-ovule ratio, artificial pollination and bagging were used to measure the breeding system. The variation of morphology and quantity of different parts of flowers occurred commonly. Flowering lasted 7-9 days. During the flowering course, the stamen closed to the center gradually and finally surrounded the pistil. S. chinensis is a species of protogynous, the female organ mature before male organ and there is no obvious herkogamy. The flowering course for one flower of this species can be divided into six periods based on the flower morphology and gender function expression： Bud stage, Prophase of flowering, Female stage, Bisexual stage, Male stage, and Fade stage. The outcrossing index and pollen-ovule ratio of S. chinensis were 3 and 29571 ± 5839, respectively. The results of pollination experiments showed that there is no apomixes, it is self-compatibility, and entomoplily playes a larger role in the process of pollination. These indicated that outcrossing is the main form in breeding system of S. chinensis and it is also self compatibility. Thus S. chinensis appeares to have a mixed mating system.