中国-喜马拉雅草玉梅繁殖生物学及生态适应研究 
张舒 
学位类型博士
导师王红
2010-11
学位授予单位中国科学院研究生院
学位专业植物学
摘要中国——喜马拉雅作为全球生物多样性最丰富的地区之一,到目前为止对该地区植物的繁育特性和生态适应机制的研究相对匮乏。毛茛科银莲花属草玉梅(Anemone rivularis),主要分布于中国-喜马拉雅地区,具有独特的花部向日运动和性分配策略,是理想的研究类群。本文以草玉梅为研究对象,选择云南西北部丽江玉龙雪山作为研究地,较深入地探讨了其繁殖生物学和生态适应机制。主要研究结果如下:1 繁殖生物学, 研究了草玉梅的交配系统、花寿命、花形态特征及传粉机制。结果表明:草玉梅为多年生具根状茎的雌雄同花植物,具有向顶型聚伞花序,且为雌蕊先熟、自交亲和,不同于已报道的银莲花属自交不亲和种类。在自然传粉条件下结实率高达70%以上,表明不存在花粉限制。人工异花授粉处理的结实率显著高于自花授粉,是以异花传粉为主的混合交配系统。结果支持多年生草本植物偏向于选择异交的繁殖策略。在高海拔特殊生境,草玉梅演化出的繁殖模式以减少自花授粉为主要趋势,有利于保障其繁殖成功。2 花向日性, 研究了草玉梅花向日行为的运动形式、机制、影响因素和适应意义。结果显示:自然条件下和去除雌雄蕊处理的花在白天能够精确追踪太阳,夜晚花被闭合;而去除花被后向日性彻底消失,花梗始终垂直向上,表明花被是向日运动的驱动者。花向日性依赖于蓝光而对红光不敏感,推测花被能够接受光信号,并导致花梗两侧细胞发生不同的伸长率,从而驱动花梗向日弯曲。草玉梅的昼夜向日运动与花内温度存在密切关系。相比去除花被处理的花温度而言,自然条件下的花内温度波动范围较窄,从而维持花内雌雄蕊在适宜的功能温度范围内。草玉梅的花向日性为雄蕊、雌蕊的发育提供了重要的繁殖保障,而且有助于吸引昆虫访花。3 性分配策略, 研究了草玉梅花序内的花各器官、雌雄功能、繁殖适合度,以及性分配假说。结果表明:草玉梅和很多被子植物类群一样具有典型的向顶型花序(基部花早开,顶部花晚开),但其性分配策略却有所不同。花序内从基部花到顶部花产生的胚珠数量增加而花粉数量减少,P/O值下降,即晚期花表现出相对偏雌性功能的资源分配。自然条件下花序不同位置的结实率保持恒定,而心皮和雄蕊与花尺寸间存在共变关系,而基部花去除后并未促进顶部花结实率的升高,证明该植物不存在花序内的繁殖资源竞争,推测其花展示和花部构成的资源分配在开花前就已固定。认为交配环境差异是导致花序内性分配差异的主要因素。
资助项目Until now, little data about the plant reproductive characters and ecological adaptation have been documented in the species-rich Sino-Himalaya region. Anemone rivularis (Ranunculaceae), mainly occurs in this area, and is of particular interest for its unique flower heliotropic movement and sex allocation strategy. In this study, we investigated the reproductive biology and adaptation mechanism of A. rivularis on the Yulong Snow Mountain Lijiang, northwestern Yunnan. The main results were summarized as follows: 1 Reproductive biology, The mating system, flowering phenology, floral morphology and pollination efficiency were examined in Anemone rivularis. This species is a perennial plant with hermaphroditic flowers, and its inflorescence is an acropetal cyme with protogynous flowers. In contrast to some self-incompatible species reported in Anemone, our results proved that A. rivularis was self-compatible. The seed set under natural pollination was more than 70%, indicating that there was no pollen limitation. Meanwhile, the seed set of artificial-cross-pollinated flowers was significantly higher than that of artificial-self-pollinated flowers, suggesting that the mixed mating system of A. rivularis was based on cross-pollination, and the results also supported a favor of outcrossing reproductive strategy for perennial herbs as some previous reports. Clearly, the reproductive strategy of A. rivularis prefer to cross-pollination in the alpine Sino-Himalayan region, in order to improve the reproductive fitness. 2 Flower heliotropism, The flower heliotropic movement mechanism, influences and adaptive significance were investigated in Anemone rivularis. The results indicated that under natural conditions, a treatment of pistils and stamens removal, flowers of A. rivularis retained accurately sun-tracking behavior through daytime, and the petals were found to close in the evening; but flowers would lose heliotropic movement if tepals were removed, with peduncles keeping a vertical orientation. This indicated that the tepals were crucial for heliotropic behavior. The flower heliotropism of A. rivularis was sensitive to blue light frequencies rather than red frequencies, suggesting that the light signal must be received by tepals, which driving the peduncles to bend due to differential cell elongation along the two sides of peduncle. Furthermore, there was a close relationship between diurnal heliotropic movements and temperature of flower interior in A. rivularis. Flowers with tepals could provide a relatively narrow range of temperatures, in comparison with flowers lacking tepals, in order to maintain reproductive organs in functional floral temperature range. Our study demonstrated that both the development of pistils and stamens and the visiting of insects could benefit from flower heliotropism in A. rivularis.3 Sex allocation, Floral traits, male and female functions, reproductive fitness, and sex allocation hypotheses were assessed in intra-inflorescence of Anemone rivularis. Though the inflorescence showed an acropetal flower-opening sequence as well as in many flowering species (early flowers are proximal and late flowers are distal), it engaged different sex allocation strategy. Our observations documented that the late-opening flowers of each inflorescence produce significantly more ovules and fewer pollen grains compared to early-opening flowers, and the pollen:ovule ratio (P:O) declined obviously from primary flower position to tertiary flower position, suggesting that later flowers would tend to favor female-bias investment. The nature-pollinating seed set among flower positions was constant, and there was no resource trade-off between flower size and sexual organs in this species, and the first-removal treatment did not lead to a significant increase in seed set of flowers in the later position. Thus, early-opening flower may not represent a significant competitor for resources with late-opening flowers on the same inflorescence, suggesting that the pattern of floral design and floral display may be determined prior to flowering and is inalterable by resources during flowering. So the female-biased allocation of distal flowers in A. rivularis may be resulted from the the selection by variation in the mating environment.
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/16026
专题昆明植物所硕博研究生毕业学位论文
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张舒 . 中国-喜马拉雅草玉梅繁殖生物学及生态适应研究 [D]. 中国科学院研究生院,2010.
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