【摘要】 有性繁殖是克隆植物适应不稳定环境和物种地理迁移的重要手段.分布于欧洲的克隆植物北极花因其有性繁殖率过低而濒危,新疆位于北极花欧亚分布区的边缘居群,该居群有着怎样的有性繁殖状态与传粉模式仍不清楚.研究表明:1)北极花单花期4～5d,花开放时,花冠内壁具毛状附属物,交叉成网状覆盖在雄蕊上,随着毛状附属物的逐渐倒伏,二强雄蕊两两序次呈现;2)自然状态下,80%以上的柱头上有充足的花粉,且能正常萌发,但能够生长到子房的花粉管数量仅占总花粉数的1/3左右;3)北极花的访花者主要有蝇、食蚜蝇、独居蜂,访花频率为0.102 4±0.056 7次/花/h.但传粉距离很短,主要集中在0～20cm范围之内;4)结实初期北极花的结实率高达82.18±1.48%,而后期大量脱落,仅为34.85±4.18%.北极花的克隆构型、雌雄异位、单花及花粉的序次呈现等成为延长散粉期、促进异交的重要性状;但较短的传粉距离,使其仍然不能避免高比例的同株异花授粉,以及由此导致的雌、雄性适合度代价及低的有性繁殖率.更多还原

【Abstract】 It’s one of the most important methods for clonal plants to fit for unstable environments and species geographic migration through sexual reproduction. The phenomenon has been reported that Linnaea borealis has endangered due to the low sexual reproduction in European populations. The sexual reproduction and pollination mode of populations, a peripheral population of Eurasia distribution area, in Xinjiang locating northwestern China are not clear. So researches on floral syndrome, pollination mode and fruit-set were carried out. Results showed that: 1) The individual flowering lasted for 4-5 days with hair appendages crossing as a web on the corolla inner wall, and coving the stamens during opening. With the hairs lodging, the didynamous stamens appear in pairs sequentially. 2) About 80 % of stigmas owned pollen enough which could germinate easy on stigmas, but only 1/3 of pollen grains can continue to grow with pollen tubes accessing to the ovary. 3) Major visitors were flies, hoverflies and solitary bees with visiting frequency of 0.102 4±0.056 7 times/per flower/per hour. But the pollination distance was very short, which mainly focused on the range of 0-20 cm. 4) The fruit-set rate was high with 82.18±1.48% at the beginning of fruit set period, but falled drop to 34.85±4.18% at mature period due to the fruits falling off gradually. The important traits related to extending floral show and promotting cross-pollination, such as clonal architecture,herkogamy, gradual presentation of flower and pollen et al in Linnaea borealis, fell flat on account of the short pollination distance which leaded to high geitonogamy ratio, male/female fitness cost as well as low sexual reproduction ratio.更多还原