【作者】 沈浩；

【导师】 刘登义；

【作者基本信息】 安徽师范大学 ， 生态学， 2002， 硕士

【摘要】 生物多样性是生物及其与环境之间形成的生态复合体以及与此相关的各种生态过程的总和，是生命系统的基本特征。包括多个层次或水平—基因、细胞、组织、器官、种群、物种、群落、生态系统、景观。但在理论与实践上较重要、研究较多的主要有基因多样性(或遗传多样性)、物种多样性和生态系统多样性。 保护生物学是一门综合性的多学科交叉的学科，从某种意义上说，保护生物学是研究生物多样性保护的科学，有两个目标：一是了解人类活动对物种、群落和生态系统的影响；一是发展实用的方法来阻止物种灭绝，并力图恢复濒危物种在生态系统中的正常功能。当前保护生物学研究的一个热点问题是物种濒危及灭绝机制的研究。中国植物红皮书第一卷将我国植物物种濒危等级标准划分为“濒危”、“稀有”和“渐危”3个等级。濒危植物保护生物学旨在针对濒危植物特点，阐明植物濒危的内在机理与外在因素，提出解除濒危的对策与措施。 黄山花楸(Sorbus amabilis Cheng ex Y(?))隶属于蔷薇科(Rosaceae)花楸属(Sorbus)，为我国华东特有种，是极为珍贵的高山观赏树种，又可用于建筑和制药。近年来其分布范围和数量正日益减少，1984年该种已被列为国家三级保护植物。 本文分别从黄山花楸的地理分布、生物学特性、生态学与繁殖生物学特征以及种群遗传多样性等方面探讨了黄山花楸的致濒机制，并提出了相应的解危措施和保护对策。结果如下： 1、黄山花楸自然分布于我国华东地区安徽、湖北、浙江、福建等省的高海拔山地，黄山、大别山区为其中心产地。从其分布区内种群的分布格局来说，呈狭域岛屿状星散间断分布，植株稀少，多成疏散的孤立木生长于狭小范围。 2、黄山花楸适宜生长在温凉、湿润、云雾多、湿度大、土层较深、腐殖质含量丰富、排水良好和偏酸性的暗黄棕壤中，对光照、温度和湿度的要求较高。 3、黄山花楸偶从树干基部萌生无性系小株，但以有性生殖为主。种子在合适的生境条件下萌发，子叶出土。自然生境下黄山花楸种群扩散的唯 一方式是种子散布。 4、黄山花揪在其分布区内为集群分布，大都为小种群或较小种群， 种群规模变小的趋势明显，种群间隔距离较大，而种群规模变小是物种趋 向濒危的特征之一。黄山花揪对光照的要求较高，在群落中仅能主于林边 或林冠空隙处。作为群落中的伴生树种黄山花揪处于从属地位或较次要的 地位，一般不具备较大的种间竞争优势。林分郁闭度过小或过大均不利于 其生存。 5、黄山花揪种群在年龄结构上为衰退型种群，幼龄个体数不足成为黄 山花揪种群发展的限制性因子。黄山花揪天然更新能力差，导致林下天然 更新苗严重缺乏。成年个体在群落演替过程中由于在竞争上处于劣势地位， 从而使其种群出观逐渐衰退迹象。 6、在不同年份、不同生境条件（尤其是光照和温度什，黄山花揪的花 期和果期有所差异。黄山花揪的开花习性与所在生境中的光照条件有显著 的相关性。不同海拔和光照条件下的黄山花揪植株，每株的花序数目及每 个花序的花朵数目也有所不同。 7、黄山花揪的种子质量很差、生活力不高，是限制种群的生存与扩展 和导致黄山花揪濒危的重要因素。 8、对黄山花揪种子萌发生物学特性的研究结果表明：＊）种子形态成熟 后不能马上发芽，冬天休眠。o）在野外各种不同具代表性的生境中，种子 萌发率均很低，仅9．28％左右。m60％日照条件下的种子的萌发率最高， 各光照条件下种子萌发率差异显著。O）种子在 5～25 oC温度范围内都可以 萌发，萌发的最适温度范围为 10毛0 oC。（）黄山花揪种子萌发的最适温度 范围基本上与其分布区春天的温度条件一致，说明春天的温度条件不是其 种子萌发的限制因子。问黄山花揪种子经过低温冷冻催芽处理后的萌发率 大幅度提高，为黄山花揪的种子繁育提供了重要的参考价值。 9、利用 RAPD技术，对黄山花揪自然分布区的 13个自然种群的遗传 多样性进行了研究。从40个10碱基随机引物中筛选出能产生稳定多态性 标记的引物14个，共扩增出105个位点，其中多态性位点30个，占28石％。 应用UPGMA法和NeighborJoining法对遗传距离进行聚类分析构建树系 图。分析结果表明：＊）黄山花揪自然种群具有较低的遗传多样性，对环境 变化的适应能力较差：（）黄山花揪种群间的遗传差异与其地理分布有关；（） 黄山花揪自身的特殊进化历史、人为砍伐以及自然灾害伙灾、病虫害等）和 小种群的遗传漂变作用是黄山花揪遗传多样性水平低的主要原因，也是其 濒危的主要原因。 10、历史时代气?更多还原

【Abstract】 Biological diversity or biodiversity is the complexity of living organisms, as well as all relevant ecological processes. Biodiversity is the fundamental feature of all life systems. Biodiversity exists at a variety of biological levels such as genes, cells, tissues, organs, populations, species, communities, ecosystems and landscapes. Most of biodiversity studies have been carried out on the three levels genetic diversity (gene diversity), species diversity and ecosystem diversity.Conservation biology is a synthetic branch of science, studying biodiversity conservation. One objective of conservation biology is to understand the effect of human activities on species, communities and ecosystems, the other is to develop practical methods to keep species from extinction, and to recover the normal functions of endangering species in the ecosystem. The key research field of conservation biology is to study the mechanisms of species endangering and extinct. China Plant Red Data Book (Vol.1) classified the threatened species as endangered, rare and vulnerable ones. The conservation biology for endangered plant species aims to clarify the internal mechanism and external factors of plant species’ endangerment to develop ways and measures to keep the species from endangerment.Sorbus amabilis Cheng ex Yii belongs to Rosaceae and Sorbus, and an endemic species of East China, being an ornamental or used as architecture and pharmacy material. Its distribution area and amounts are declining, which was listed in the third class of the national protection plant species in 1984.This paper studied the biological and ecological aspects of S. amabilis, including geographical distribution, biological characteristics, ecology, propagation biology and genetic diversity. The threatening factors have been analyzed and several measures for effective preserving the species have also been proposed. The results are as follows:1. S. amabilis distributes in Anhui, Hubei, Zhejiang and Fujian provinces. The natural distribution area of S. amabilis is very narrow, fragmentary andclumped. It is confined to mountainous region, with an altitude of 900-2000m, 晈ith Mount Huangshan and Mount Dabieshan as its distributing center.2. S. amabilis is suitable to cool, moist, misty and humid habitat, with humus-riched dark yellow-brown acidic soil well-drained and strict demands for light, temperature and humidity.3. S. amabilis propagated mainly by seeds, occasionally by forming clones. Seeds germinated into seedlings in suitable habitat, with the two cotyledons coming up out of soil.4. Most of the S. amabilis populations are small or rather small. As S. amabilis has a high demand for light, it lives at the edge or the gap of the forest. As an accompany species in its communities, S. amabilis does not have a strong competition predominance against other species.5. In most of the S. amabilis populations, the young individuals are few, the adult ones are in an inferior position in community succession, and the population size is tending to decline.6. The flowering and fruiting dates varied in different years and in different habitats (especially light and temperature conditions). The flowering characteristics had a distinct correlation with the factor of light. Mean number of inflorescence per plant, and flowers per inflorescence were different from each other with the change of altitude and light.7. The seed quality of S. amabilis was very poor, and percentage of seeds with vitality was low, which restricts the spreading of populations of S. amabilis.8. Seed germination biology of S. amabilis was studied. The results showed: (1) The freshly harvested seeds were in dormancy during winter; (2) In the different natural habitats, the germination rates of the seeds were very low (around 8.92%); (3) Under 60% natural light conditions, the percentage of germination was highest. The germination rates of the seeds showed different from one another under different light conditions; (4) The temperature rang更多还原