Abstract: Anemone obtusiloba is an indicative plant of grassland degradation that plays an important role as a dominant poisonous weed in eastern Qinghai-Tibet Plateau. However, there are few studies about its reproductive characteristics. The flower characteristic and breeding system of Anemone obtusiloba were studied by field location investigations using data of TTC method, benzidine hydrogen peroxide method, pollen-ovule ratio (P/O), out crossing index (OCI), and bagging experiments. Results showed: the life span of individual flower was about 4~5 days; during the flowering phase, the pistil matured before stamens; stigma receptivity and pollen vitality had a period of overlap, and they were the highest at 12:00-14:00 of the day; a out-crossing partially self-compatible, and requiring pollinations can be reflected by OCI=4.The pollen-ovule ratio (P/O) was approximately 86. Based on Cruden's criterion, the breeding system could be termed as facultative autogamy. According to the results of emasculation, bagging, and artificial pollination, it was agamospermy, and the breeding system of Anemone obtusiloba was determined to be self-compatible largely, and only occasionally requiring pollinators. It was conclude that the breeding system of Anemone obtusiloba mixes with se1f-pollination and out-crossing, and tended to selfing, which can be regarded as an adaptive strategy for reproduction under unfavorable environmental conditions.

Key words: Anemone obtusiloba, Breeding system, Pollen viability, Stigma receptivity, Flower characteristic

摘要： 钝裂银莲花(Anemone obtusiloba)是青藏高原东部常见的一种优势毒杂草, 也是一种重要的草原退化指示植物,目前对其繁殖特性研究甚少。通过野外定位观察, 运用TTC法、联苯胺-过氧化氢法、花粉-胚珠比(P/O)、杂交指数、人工授粉和套袋试验等方法, 首次对该物种的花部特征及繁育系统进行了研究。结果表明:该物种单花花期为4~5 d, 花雌雄异熟, 雌蕊先熟, 单花花粉活力和柱头可授期之间也存在一段时间的重叠, 钝裂银莲花最佳授粉时间为一天中的12:00-14:00左右; 按照杂交指数, 其繁育系统属于异交、部分自交亲和, 需要传粉者; P/O约为86, 判断繁育系统类型为兼性自交; 套袋试验显示, 钝裂银莲花自然条件下存在无融合生殖现象, 繁育系统为自交、异交亲和, 以自交为主, 但有时也需要传粉者; 由此推断, 该物种的繁育类型为混交的交配系统, 即自交和异交并存, 但倾向于自交。在长期的环境选择压力下, 钝裂银莲花倾向于自交, 可能是对不利环境条件的一种适应进化策略。

关键词: 钝裂银莲花, 繁育系统, 花粉活力, 柱头可授性, 花部特征