【作者】 张震；

【导师】 蒋高明； 汪诗平；

【作者基本信息】 中国科学院研究生院（植物研究所） ， 生态学， 2006， 博士

【摘要】 植物在长期的进化过程中,已经对其生存环境具备了各种适应对策。放牧影响下草原植物的生态适应策略,决定了其是否能够忍耐或者适应放牧生境从而维持自身的生存和种群的延续。研究植食性动物对植物的影响有助于制定合理的放牧制度和草地利用方式,从而为防止草原退化和恢复退化草地提供重要的理论依据;同时研究植物对放牧的响应策略,对于草原生物多样性的保护和草原生物资源的合理利用具有重要的理论和实践意义。本文以中科院内蒙古草原生态系统定位研究站放牧综合试验样地中的小叶锦鸡儿为主要研究对象。通过长期不同放牧强度的放牧试验和唾液涂抹等模拟试验,从形态学、有性生殖、种子萌发和遗传多样性等方面,探讨了小叶锦鸡儿对放牧家畜(绵羊)采食的生物学响应。本研究得到以下主要结论:1.通过小叶锦鸡儿形态和有性生殖的实验,可以看到放牧改变了该种植物的形态和生殖特性,不同放牧强度对其影响的程度是不相同的。在啃食压力下,小叶锦鸡儿的营养、生殖和防御之间存在消长关系。随着放牧强度的增加,小叶锦鸡儿对营养器官和有性生殖器官的投资均减少,而对防御器官的投资有增加的趋势,主要体现在:个体的小型化(植株高度、叶轴长度、小叶大小)和果荚数目及成熟种子数都随着放牧强度的增加而明显减少;物理性防御器官――刺,其密度和长度都明显的增加。同时,放牧也对植物花粉的品质产生了消极影响。2.放牧不仅影响了植物体本身的生物学特性,而且影响了子代的生物学特性。不同放牧强度下的植株产生的种子,其萌发速率明显不同。同时放牧强度和沙埋深度对小叶锦鸡儿的出苗率均具有显著影响,随着沙埋深度增加,出苗率明显降低,0～2cm是其适宜出苗的沙埋深度;浅层沙埋处理下,轻度放牧和重度放牧的出苗率差异显著。与轻度放牧相比,重牧条件下同一沙埋深度的种子出苗时间明显推迟;在相同放牧压力下,沙埋深度也影响了出苗时间。更多还原

【Abstract】 Although plants can’t move away from the attacks of herbivore, they are not completely subject to the herbivore. In the long evolutionary history, some plants have developed certain defense mechanisms against their predators and parasites. The adaptive mechanisms of host plant to grazing are the key to keep their living and their population multiplication. It is helpful to manage and utilize grassland if we can understand the effect of herbivore on host plant. We hope this information is helpful to conserve the biodiversity and utilize rationally the resource of grassland.A legume shrub, Caragana microphylla which randomly distributed the grazing experimental field of the Inner Mongolia Grassland Ecosystem Research Station was selected to study the biological response to grazing through many ways, such as morphology, application sheep saliva, sexual reproduction, seed germination and genetic polymorphism. According to the experiments, we found four results:1. Long grazing history had significantly influenced the characteristics of morphology and reproduction of C. microphylla under different grazing intensities. Under grazing treatments, there were trade-offs among vegetative, reproductive growth and physical defense. With increasing browsing intensity, the host plants decreased their investment in vegetative growth and reproduction, and increased investment in physical defense organs, as well as, individual miniaturization, decrease of pods and ripe seeds, increase of spine density and length. Additionally, the pollen quality was negatively influenced更多还原