【作者】 郭力华；

【导师】 杨允菲； 李建东；

【作者基本信息】 东北师范大学 ， 生态学， 2004， 博士

【摘要】 地毯草 Carpetgrass(Axonpus compressus(Sw．) Beauv．)、竹节草 Aciculate Chrysopogon(Chrysopogon aciculatus(Retz．) Trin．)、狗牙根 Bermuda Grass(Cynodon dactylon(L．) Pers．)是广布于中国热带地区海南岛的多年生匍匐茎禾草，是典型的无性系植物和热带次生植被的主要占据类群，也是具有草坪种质资源开发前景的植物类群。研究其种群动态、种群结构、种群生长与繁殖对策，从而揭示热带地区匍匐茎禾草适应特性的生物生态学机理及其进化意义，对于丰富植物生态学理论和应用研究具有重要意义。本文以该三种禾草为研究对象，通过对其人工种植的实验无性系种群的生长规律、时空动态研究，以及对相同和不同生境的天然种群生殖特性研究，得出如下结论： 1 三种禾草无性系扩展表现出相同规律，即以最大可能伸长主茎从而占据生态位空间。主茎长的扩展范围排序为：地毯草＞狗牙根＞竹节草。增长率随时间推移而下降的趋势、主茎分株数与主茎长度之间显著的正相关以及间隔子动态变化规律，均揭示了无性系扩展形成的空间结构是聚集与母株周围一定范围内，扩展依赖于母株和先生分蘖株对无性系的贡献。 2 在空间环境足够的情况下，竹节草和地毯草无性系的扩展并不会出现主茎长度的“疯长”，而是保持方阵型的生长格局。两种植物的数量和生物量在空间上的分布与配置，均体现了无性系植物在生长和扩展功能之间的物质和能量的权衡，反映出同生活型匍匐茎禾草的趋同生态适应对策。 3 三种禾草无性系叶种群具有相同生长和发展规律。叶片数量及叶数增长率的变化暗示物质生产的变化和投入目标的变化。主茎总叶数与主茎伸长的体现了种群的协调发展规律。 4 地毯草与竹节草种群生物量的配置规律揭示了无性系通过营养体扩展的方式占据更大空间的能力是有限的。这种一致性体现出它们对生态环境适应的趋同性。而两者变化的差异又显示了物种间生态位的不同。无性系主茎节数与节长的极显著相关性以及节数节长对时间的拟合模型提示了甸旬茎禾草营养繁殖能力的相同变化规律。天然种群中就生殖枝而言，三种禾草的生殖生长比率和生殖分配大小顺序为:地毯草>竹节草>狗牙根。三种禾草的生殖生长比率和生殖分配与有性生殖的其他数量特征，如穗长，穗重，株高，株重等之间关系达到显著或极显著相关。表明旬旬茎无性系植物种群的有性生殖过程受植物自身生长规律的调控;而生长时间和物候对其生殖对策均有重要的生态作用。不同生态环境下狗牙根种群生殖特性表现出物种的遗传性和生态可塑性。关键词:热带地区甸旬茎植物无性系种群生态更多还原

【Abstract】 Carpetgrass (Axonpus compressus (Sw.) Beauv.), Aciculate Chrysopogon {Chrysopogon aciculatus (Retz.) Trin. ) and Bermuda Grass (Cynodon dactylon (L.) Pers.) are three perennial stoloniferous geasses widely distributed in the Hainan Island of tropical regions of China. They are typical clonal plants for exploiting germplasm of lawn and also are the main occupied population of tropical secondary vegetation. Researches on the population dynamic, population growth and the reproductive strategy of the three stoloniferous grasses from tropical regions was important and useful for revealing the mechanism of bioecological adaptation as well as that in enriching the ecological theory and application. The growth rules, dynamics of temporal and special were performed based on the research of three planted clones. Furthermore, the reproductive characteristics of natural population were also tested in the same or different habitats. Results showed that:1 Three species of clone taken on the similar type of extending. The main stolon elongated as long as possible to occupied the ecological niche. The expending size of the main stolon was Carpetgrass> Bermuda Grass> Aciculate Chrysopogon, and its increasing rate reduced vary with time. The positive correlation between the number of ramets and the length of main stolon as well as the dynamic change of spacer were all showed that the spacial structure of clone was gathered around genet and the extending of clone was due to the contribution of genets and the senior ramets.2 Aciculate Chrysopogon and Carpetgrass clone always keep the growth pattern of matrix and not limitless in enough space. The number and biomass allocation of two grasses show that there are matter and energy trade-off between the growth and the extending and it is the convergentadaptation of stoloniferous grasses that own the same life form.3 The leaf population of the three grasses owns the same growth and development rule. Number of leaves and its increasing rate implied that the change of the matter production and invested target. The changes of total leaves from main stolon and the elongating of main stolon indicated the harmonized development rules.4 The rule of biomass allocations of Axonpus compressus(Sw.) Beauv. and Chrysopogon aciculatus (Retz.) Trin. ) populations disclosed that the capacity of expanding vegetation occupying the space were limited. This concordance embodied their convergency adapting to the environment. While the variational difference of two species showed the difference of ecological niches between species.5 There were significant relationship between the number of nodes of the main stems and the length of the nodes, and the modules of the numbers and the length of the nodes varying with the time disclosed the same changing rule of vegetative propagation capacity of stoloniferous gramineae herbages.6 As for reproductive branch of the natural populations, the orders of the reproductive ratios and reproductive allocation of the three gramineae herbages were Axonpus compressusiSw.) Beauv.> Chrysopogon aciculatus (Retz.) Trin.> Cynodon dactylon (L.) Pers..There were significant and very significant relationships between the reproductive ratios and reproductive allocation of the three gramineae herbages and other amphigenetic quantitative characteristics,such as the length of the spike, the weight of the spike, the height of the ramets, the weight of the ramets, et al.,which showed that amphigenetic process of stoloniferous clonal species populations were controlled by growth rhythms of the species themselves, and the growth time and biotemperature were vital ecological effect to the reproductive strategies.7 Reproductive characteristics of Cynodon dactylon (L.) Pers. populations in different environments represented heredity and plasticity of the species.更多还原