【作者】 王彦靖；

【导师】 穆春生；

【作者基本信息】 东北师范大学 ， 生态学， 2011， 博士

【摘要】 开花植物的生殖生态学研究对于确定种子的结实障碍、保存,了解传粉系统及对调节种群的遗传结构的繁育系统具有非常重要的意义,而豆科牧草又为评价自交亲和,异交率和近亲交配阻抑之间相互作用等提供重要的机会,本文以松嫩草原五脉山黧豆(Lathyrus quinquenervius),澳大利亚Cullen australasicum等多种多年生豆科牧草为实验材料,分别对繁育系统,传粉系统,花形态,生殖分配,种子萌发等生殖生态学方面的问题进行调查,具体研究结果如下:(1)对多年生豆科牧草五脉山黧豆花器结构,传粉系统及繁育系统的研究表明:雌雄蕊在空间上不分离,柱头的可授性与花粉活力同步,为自花授粉提供时空上的便利条件;传粉系统由风媒和昆虫诱导组成,主要传粉者为蜜蜂;按照Dafni和Cruden的标准,繁育系统为自交亲和,兼性异交,有时需要传粉者。自然条件下结荚率很低,人工自花授粉和异花授粉下的结荚率与对照差异不显著。荧光显微镜下人工自交和异交后花粉管生长没有差异,在柱头萌发及生长没有明显的自交不亲和现象发生。以上结果显示,雌雄同熟的五脉山黧豆是自交亲和物种,展示了混合的交配系统,花部特征在长期的进化过程中形成了一种繁殖保障。繁育系统有由异交向自交演化的趋势,以无性繁殖和有性繁殖并存的生殖方式作为一种生殖补偿机制。(2)对来自澳大利亚不同地区的Cullen australasicum繁育系统研究结果显示,温室授粉实验中,五个编号中的四个需要外界的诱导来起到传粉的作用,人工弹花诱导是最为有效的授粉途径。扫描电镜的实验结果显示,该种具有二态型柱头。在花药开裂之前的早期花蕾阶段柱头可授性显著低于其他时期。在田间,粉红色的花朵相对于蓝色的花朵对访花昆虫例如蜜蜂和体型较小的昆虫具有更强的吸引力。对该种的研究显示该种具有很宽范围的异交潜力。当前实验结果表明,Cullen australasicum是自交亲和种,需要外界诱导使柱头表面膜破裂以起到传粉作用。(3)对五脉山黧豆的生殖分配研究结果表明,不同的生境和生育阶段,生殖分配的比例变化不大。五脉山黧豆以发达的地下根茎系统,维持自身生长所需养分,无性繁殖的投资占生殖投资的比例大于有性繁殖的投资。不同施肥条件下,生殖分配比例没有显著变化,但在盛花期施肥,有利于地上各项生育指标的增长。(4)对十三种豆科苜蓿属,包括野生黄花苜蓿,野生扁蓿豆和紫花苜蓿的11个品种的PEG模拟干旱胁迫研究结果显示,随着渗透胁迫强度的增加,各供试种的生物学指标发生变化且变化趋势不同,供试种子的抗旱性大致为扁蓿豆<黄花苜蓿<紫花苜蓿品种,以上各参数可以作为衡量牧草抗旱性的指标。更多还原

【Abstract】 The reproductive biology of flowering plants is important for determining barriers to seed and fruit set, for conservation, and for understanding pollination and breeding systems that regulate the genetic structure of populations. Legumes offer an interesting opportunity to evaluate the interaction between self-compatibility, out-crossing rate and inbreeding depression, as many annual members of the group reproduce through a combination of selfing and outcrossing. We conducted the experiments in breeding system, pollination system, floral morphology, seed germination, and reproductive allocation on Lathyrus quinquenervius, Australian native Cullen australasicum and some other pasture legume. We got the conclusions as follows:(1) This paper examines the floral structure, pollination system and the breeding system in a population of L. quinquenervius, a perennial pasture legume. The pistil and the androecia aren’t separate in space. A single florescence and the whole florescence are 3~4 days and 40 days, respectively. The stigma receptivity is almost synchronizing with the pollen viability and providing the opptunity for selfing pollination. Pollination system comprises anemophily and insect vector, and the bees were the main pollinator. According the Dafni and Cruden’criterion, the breeding system is self-compatibility and need pollinator. Seed set following spontaneous pollination was low, following hand self-pollination and cross-pollination were not significantly lower than the contrast. There were not significant differents on the pollen tube growth between hand self-pollination and cross-pollination; it means no self-incompatibility on the stigma. Hermaphroditic homogamous L. quinquenervius is a self-compatibility species, sometimes requires floral visitors such as honeybees to bring about pollination and exhibits a mixed mating system.(2) The study on breeding system on the five accession of Cullen australasicum (syn. Psoralea australasica) in the glasshouse indicated that four of the accessions showed the need for an external tripping agent to bring about pollination and that hand-tripping was the most efficient method. A scanning electron microscopy study revealed there are two types of stigmas in this species. Stigma receptivity was significantly lower at the early bud stage before anther dehiscence. The pink flowers have more attraction on the small insects such as bees than the bule ones. The results show that C. australasicum is a self-compatible species comprising accessions with a wide range of outcrossing potential, need trip on the stigma to rupture the stigmatic surface and pollination occurred. (3)Percentage of the reproductive allocation changing not too much under the different aere and stage, Lathyrus quinquenervius have developed rhizome and depend on them to survive. The percentage of investment on asexual reproduction was more than sexual reproduction. The percentage of reproductive allocation was not significant changing a lot under different fertilization, but after fertilizated during the grand anthesis, the plant height, the numbers of the leaves and so on were significantly more than the contrast.(4)The drought resistance of Melilotoides ruthenica (L.) Sojak, Medicago falcata L. and eleven varieties of Medicago sativa L. at seeds germination stage with seven osmotic potential treatments of PEG were studied. We measured the day when germination began, the germination rate, the length of the seedlings, the number of the lateral root, and the length and the width of the cotyledon. The results indicated that the biologic index of the tested samples under the different osmotic potential treatments were different, the drought resistance of Melilotoides ruthenica (L.) Sojak was lower than Medicago falcata L. and they were lower than the other varieties of Medicago sativa L. The above parameters could be the drought resistance index of the pasture legume.更多还原