【作者】 闫桂琴；

【导师】 胡正海； 赵桂仿；

【作者基本信息】 西北大学 ， 植物学， 2001， 博士

【摘要】 太白红杉（Larix Chinensis Beissn.）为我国特有种，分布区极其有限，仅分布在陕西秦岭山地2600m（太白山为2800m）~3500m海拔范围。已被列为国家二级珍稀濒危保护植物。太白红杉是秦岭山地森林最上线的唯一落叶乔木针叶林树种，是秦岭生态系统的重要组成成分。在自然物种的保存、科学研究、生态效益和经济意义等方面，都具备了被研究和保护的价值。根据现有资料分析,目前,对太白红杉的研究仅仅限于考察性的描述,系统的、尤其是定量分析比较少。本文试图通过太白红杉生物多样性的研究，从宏观生态学和微观分子生态学两个层面分析太白红杉与生境间的相互关系及其种群数量动态规律和群落学过程，预测太白红杉的遗传学命运和生存潜能，揭示太白红杉的变异规律和分化机制，探索太白红杉的致濒原因。具体内容包括:1 太白红杉种群多样性的研究从太白红杉种群的年龄结构、存活曲线、死亡龄级分布、生命表、生态位破碎环境等方面进行深入的研究，研究结果表明:太白红杉低径级和高径级的个体数量少，中径级个体数量多。幼苗的产生主要依赖于萌生，受限于林窗的形成，其数量的不足直接影响了种群的发展，有可能成为该种群致濒的重要因素。光头山、玉皇山、冰晶顶等较低海拔山地径级结构中，有不同程度的缺失，而太白山比较完整。不同样地的密度（株数·hm2）分析表明，太白山>玉皇山>光头山>冰晶顶。不同样地密度随径级的变化曲线特点是低径级密度高，高密度的径级分布区间为15-25cm。密度在不同样地平均径级上的分布规律表现为明显的负相关规律。静态生命表客观地反映了太白红杉的动态变化。表明太白红杉死亡率和危险率动态趋势基本相似。积累死亡率单调增加，生存率单调下降。生命期望的极大值对应于死亡密度的极小值。4个函数值说明了太白红杉中前期增长，后期稳定的特点。太白红杉的存活曲线表现为25cm直径前随径级增加平稳下降，35cm后在较低水平上保持平稳。曲线走向趋于Deevey的II型和III型曲线之间。死亡曲线表现为20cm前在较高水平上保持平稳，30cm后在较低水平上保持平稳。死亡高峰位于25-30cm之间，和在区间增长曲线直线下滑完全吻合。从不同的角度对太白红杉种群结构的研究表明，该种群长期适应秦岭亚高山环境<WP=7>条件，中龄级以后个体间的竞争相对平稳，数量减少趋向于稳定，说明其密度制约有着良好的自我调节能力，这正是太白红杉种群成为稳定型种群的原因所在。2太白红杉群落多样性的研究对太白红杉群落进行：1）群落种类组成的区系分析，确定占优势的区系成分；2）群落外貌分析，建立太白红杉群落的生活型谱。（同时对该群落的季相变化进行分析）；3）群落结构分析，从垂直结构和水平结构两个方面分析其生态学规律；4）群落中物种多样性的研究。研究结果表明：太白红杉群落中植物的种类组成成分比较简单，仅出现了85种种子植物。原因在于秦岭亚高山地带寒冷、风大、紫外线强等环境因素限制了许多植物的分布。从区系组成分析来看，北温带分布的种类占优势，并决定了该植物区系的性质。其它旧世界温带分布和世界分布的属也占有一定比例，但大都具有高纬、高寒分布的特性。中国特有分布的属虽然数量不多，但反映了本区的特殊性。从生活型组成的分析来看，高位芽植物占优势，这和暖温带森林气候条件下发育的群落组成非常一致，反应了暖温带季风区夏季炎热多雨，冬季寒冷而漫长的区域特点。而地下芽和一年生植物的比例偏高，则反应了秦岭亚高山地带的特点。从群落的垂直结构来看，该群落平均高度为8.6m，可分为乔木层，灌木层、草本层和地被层。从水平结构来看，整个群落呈现斑块状，分布于亚高山草甸构成的基质上，群落内常有香柏，离柱五加或冷杉等小群落镶嵌。物种多样性4种指数的分析，效果良好。H值在4个取样地段上均为草本层 >灌木层 >乔木层；在4个层次上均为太白山H值最小，太白山< 玉皇山< 光头山< 冰晶顶。J值、D值的变化趋势和H值相近，D值则相反。太白红杉是秦岭山地针叶林带最上部落叶林亚带中的优势种。区系成分和生活型组成均具北温带性质，群落结构简单，具有适应亚高山寒冷环境的生态特点。3太白红杉自然居群遗传多样性的研究 研究太白红杉种群内、种群间分子的遗传变异、以及这些分子变异与其生境或生态学之间的联系。研究结果表明：对适合太白红杉基因组DNA提取的CTAB方法进行改良，有效的去除了酚类化合物、多糖、萜类化合物和未知化合物的干扰。采用优化的RAPD反应体系（10 ng模板、300μM dNTPs、 2.5 mM Mg2-、 0.1U Taq、 8μl引物，总体积为20μl）节约简便，且扩增出的带型清晰，重复性好。本研究运用随机扩增多态DNA（RAPD）方法对太白红杉的6个居群共122个个体进行了遗传多样性检测。29个10-mer的寡核苷酸引物共检测128个位点，其中120个位点为多态位点，占0.93，牛背粱居群多态位点百分率最小（0.75）；太白山居群多态位点百分率最大（0.90）。按所检测的多态位点百分率排列各居群的顺序为：太<WP=8>白山居群>冰晶顶居群>玉皇山居群>光头山居群>佛坪居群>牛背粱居群（0.90>0.87>0.84>0.80>0.77>0.75）。以上结果说明太白红杉的遗?更多还原

【Abstract】 Larix Chinensis Beissn, which is endemice species, only distributes the zone from 2600 to 3500m altitude in Mt. Qinling, Shaanxi Province of China. This thesis mainly deals with Larix Chinensis in two aspects. One is macrocosmic ecology about the diversity of the population, the community and the landscape, and the other is the molecular ecology about the genetic diversity analysis of intrapopulations and interpopulations, with special emphasis on the cause of endangered state and conservation strategy of the species.1 The diversity of the population In Mt. Qinling 4 sampling stands were set up at Mts. Taibai, Guangtou, Yuhuangshan and bingjingding respectively. 280 plots in Larix chinensis population were investigated by the sampling method. The community feature, size-class structure, the regulation of changing density were analyzed, as well as worked out the survivorship curve, the death curve and the life table. The results indicated the populations had one peak of mortality between 25-30cm, and the survivorship curve trended to be the type between DeeveyII and III. The large size-class populations were stability and variable in small size-class population. The restricting factor for the survival and development of the population was a short seedling.2 The community diversity Based on the above plot data, Larix chinensis community characteristics were analyzed about the specific composition; the flora feature; the community physiognomy; the vertical and level structure; and the regulation of environment. The indexes of the frequency and the coverage and the species diversity (Shannon-Wiener index; Simpson index; Pielou index and Probility of Interspecies Encounter index) were measured in L. chinensis community in the sampling stands. The results were followed: (1) the community of L. chinensis apparently distributed to high-altitude montane at 2800-3500M in Qinling ranges; <WP=11>(2) the specific composition of the community is about 84 species, which the genus of the boreal temperate zone is absolute dominance. The species and quantity of hemicryptophyte were both more and larger. There was a striking dominant synusia of L. Chinensis in the L. chinensis community, which was a monodominant community. The H index of tree layer was 0.207-0.420, brush layer and herb layer1.779, 2.122-3.025 respectively. This study aims at scientific sustainable development and conservation of this rare phytobiocenose.3 the molecular ecological analysis An extraction medium with the combination of antioxidants and chelants was successfully used to obtain total DNA from the leaf tissues of L. chinensis, which can remove phenolic compound, polysaccharide and terpenoid. An economic and effective RAPD reaction system was obtained for adapting to L. chinensis RAPD markers. The optimized system include 10ng temlpate DNA, 300μM dNTPs, 2.5 mM Mg2-, 0.1U Taq DNA polymerase, 8μl Operon random primer(4pM) with 20μl of the total volume. This was the basis of large-scale reseach of many L. chinensis materials’ RAPD analysis.The genetic diversity of L. chinensis, represented by 122 individuals collected from all 6 populations (niubeiliang <n-pop>, guangtoushan <c-pop>, bingjingding <b-pop>, fuping <f-pop>, taibaishan <t-pop> and yuhuangshan populations<y-pop>), was investigated with random ampified polymorphic DNA (RAPD) markers. Twenty-nine 10-mer primers primed 128 sites, of which 120(0.93) were polymorphic. The percentage of polymorphic sites (PPS) was higher (0.90) in t-pop and lower (0.75) in n-pop. In proper order, the PPS were t->b->y->c->f->n-pop (0.90> 0.87> 0.84> 0.80> 0.77> 0.75). The result reveals higher genetic diversity level of L. Chinensis than most other conifers.To reveal the relationship to molecular variation and gene flow and the habitats, it was found that 69.49% of molecular variation existed within the populations while 30.35% of which among populations estimated by Shannon phenotypic diversity index from RAPD data. The genetic different coefficient and genetic distance between populations更多还原