摘要
云南红豆杉(Taxus yunnanensis)是分布于我国西南部及不丹和缅甸北部的红豆杉属植物。用石蜡切片法、电镜扫描和整体透明染色法观察了云南红豆杉成熟小孢子和胚珠的结构,在野外观测了云南红豆杉的花期及传粉滴的活动规律。结果显示:云南红豆杉为单核小孢子,没有气囊,有(无)活力的小孢子水合后都急剧膨胀,胚珠单个生于叶腋。云南红豆杉雄株的散粉期在11月中旬到12月中旬,胚珠下弯期从11月下旬持续到2月中旬。在雄株散粉期内及人工授粉的传粉滴持续存在的时间较短,而且授粉后不再出现,在非散粉期内的传粉滴持续存在的时间较长,而且在消失后又会重新出现。红豆杉属植物可能的传粉机制:(1)传粉滴大而且裸露,持续存在的时间较长,有助于提高传粉效率。(2)小孢子能在常温下较长时间的保持活性,不具备远距离飞行的特征,有利于在一定范围内保持较高的小孢子密度;(3)虽然小孢子散粉期短且易变,但胚珠的成熟期较长,从而保证了花期可遇。传粉期内的降水和低的种群密度可能是影响红豆杉传粉效率的主要因素。
Taxus yunnanensis, its distribution extends from Burma through southwest China to Bhutan. The structure of mature ovules and microspores were examined using paraffin embedded samples, SEM and stain-clearing. The pollen drops＇ activities were observed in the field. The results show that：The mature microspores were uninucleate, non-saccate, with numerous orbicules, and live and dead microspores expanded rapidly after hydration in vitro. A single ovule is borne in axil of a leave. The mierospores were shed from mid-November to mid-December, and base-bend ovules are found from late-November to mid- February. The existed duration of pollen drops was shorter in shedding period or with hand-pollination, and the pollen drop didn＇t reoccur once pollinated. The existed duration of pollen drops was longer after shedding time, and the pollen drops could reoccur after disappeared. The pollination mechanisms in Taxus are considered as follows： （1） The pollen drops are big and naked, and its duration is long, these can improve the pollination efficiency. （2） Microspores can keep alive in room temperature a long time, and eanu＇ t fly in long distance, this is beneficial to keep higher concentration. （3） Long duration of ovules＇ maturity can meet variable shedding period. Raining in pollination and low population density may be major factors that affect pollination efficiency.
出处
《武汉植物学研究》
CSCD
北大核心
2009年第4期441-445,共5页
Journal of Wuhan Botanical Research
基金
中国科技部科研院所社会公益研究专项(2004DIB3J104)资助
中国科技部"十五"科技支撑项目(2006BAD18B03)资助
加拿大阿尔伯塔大学益客基金会资助
南京中医药大学资源昆虫研究所所长基金(Riri200703Z
Riricaf200804M)资助~~
关键词
云南红豆杉
小孢子叶球散粉期
胚珠成熟期
传粉滴
传粉机制
Taxus yunnanensis
Duration of pollen cone shedding
Duration of ovules mature
Pollination drops
Pollination mechanism
