【作者】 潘丽芹；

【导师】 陈龙清；

【作者基本信息】 华中农业大学 ， 园林植物与观赏园艺， 2003， 硕士

【摘要】 荷叶铁线蕨(Adiantum reniforme L. var. sinense Y. X. Lin)是三峡库区特有植物，为面临灭绝的国家二级保护植物，对其进行保护生物学方面的研究很有必要。 本试验以荷叶铁线蕨为材料，通过对生态学及遗传学等方面的研究，了解其濒危的可能机制。主要内容有：1)生态学调查与分析。调查了5个自然样地，记录了34个伴生种，取10个优势种进行种群生态位宽度与生态位重叠的计算。对荷叶铁线蕨进行形态学观察和垂直生物量分配的分析。2)用等位酶标记检测荷叶铁线蕨的交配系统。采用EST、MDH、FDH、SOD和ACP等5种酶系统，分析荷叶铁线蕨的等位酶遗传变异，用间接法估算荷叶铁线蕨交配系统的特征参数——异交率t。3)用X居群的50个个体进行空间自相关分析。本试验的结果如下： 1)荷叶铁线蕨有3种生境群落结构：Ⅰ勾儿茶+南天竹+构树—鸢尾+荩草+荷叶铁线蕨(Berchemia sinica+Nandina domestica+Broussonetia kazinoki—Iris tectorum+Arthraxon hispidus+Adiantum reniforme var. sinensis)Ⅱ黄荆—荩草+荷叶铁线蕨(Vitex negundo--Arthraxon hispidus+Adiantum reniforme var. sinensis)Ⅲ勾儿茶+油茶+牡荆—鸢尾+卷柏+石韦+荷叶铁线蕨(Berchemia sinica+Camelia oleifera+Vitex negundo—Iris tectorm+Selaginella sp.+Arthraxon hispidus+Adiantum reniforme var. sinensis)。其中，Ⅲ是荷叶铁线蕨生长的最佳生境，Ⅱ是最差的。 2)生物量分布研究表明：荷叶铁线蕨的有性繁殖器官所占比例相对较高。生物量的垂直分布随植株高度的增加而增加。 3)荷叶铁线蕨的生态位宽度值较大，B_i和B_i’指数分别是0.4496和0.6888。说明荷叶铁线蕨对环境的适应能力很强，具极强的生活力。 4)荷叶铁线蕨与鸢尾的生态位重叠最大，为0.3515，表明两者间存在强烈的对自然资源的竞争。其次是与贯众，生态位重叠值为0.3389。 5)在5种酶系统中，共检测到14个位点，其中有7个多态位点。平均每位点的等位基因数为1.43---1.57。多态位点百分率较低，为0.3571—0.5。平均预期杂合度为0.177—0.284，观察杂合度为0.194—0.284。说明荷叶铁线蕨的遗传多样性是比较低的。 6)荷叶铁线蕨的异交率水平较高，为0.000-3.500。荷叶铁线蕨不同位点的异交率在同一居群内的变化很大，而不同居群间的同一酶位点的异交率差异也是较大的。这说明荷叶铁线蕨种群可能是以配子体间异交为主的混合交配体系。 7)空间自相关分析的结果表明：荷叶铁线蕨个体间的等位基因分布在空间上呈渐变的非随机分配。其空间邻域的大小约为30m。更多还原

【Abstract】 Adiantum reniforme L.var. sinense Y. X. Lin, which is the second grade national protection plant, is the special plant in Three Gorge of Yangtze River.China. At present, it faces to die out, so it is extremely necessary to research its protection biology.The experiment uses Adiantum reniforme L.var. sinense Y. X. Lin as material to understand its mating system through the research of ecology and genetics. The main contents include: 1) the investigation and analysis in ecology. There are five natural sample zones of Adiantum reniforme L.var. sinense Y. X. Lin investigated, and recorded 34 species. 10 dominant species were used to calculate the niche width of populations and the niche overlap interpopulations. Several adult individuals from each population at random were observed their morphologic characters, and then to analyse the distribution of the vertical biology yield. 2) Studies on the mating system of Adiantum reniforme L.var. sinense Y. X. Lin using Allzyome Marker. The experiment employ six enzymes: EST, MDH, FDH, GDH, SOD and ACP , using their polymtic locus to analyse the allele gene frequency, the number of the effective allele gene. Hardy-Weinberg equilibrium test, the frequency of expected and observed heterozygosity and Chi-Square(X2) test of fixation index. Finally, the character parameter of the mating system Adiantum reniformeL.var. sinense Y. X. Lin -outcrossing ratio was estimated indirectly. 3 ) Spatialautocorrelation study of Adiantum reniforme var.sinense.The results are followed:1) Adiantum reniforme L.var. sinense Y. X. Lin has three kinds of population structures:.1. Berchamia sinica +Broussone tia kazinoki-Iris tectorm + Arthroxon hi spidus+ Adiantum reniforme var. sinensis. 2. Berchamia sinica + Vitex negundo-Iristectorm+Selaginella sp.+Arthroxon hispidus+Adiantum reniforme var. sinensis. 3. Vitex negundo-Arthroxon hispidus+ Adiantum reni forme var. sinensis. the second population structure is the best environment but the third one is the worst in three population.2) the sexual reproduction organs in Adiantum reniforme L.var. sinense Y. X. Lin holds comparatively high ratio, the vertical distribution of biology yield increases with plant height. This correspond to its biology character.3) Niche width of Adiantum reniforme L.var. sinense Y. X. Lin is high comparatively. The index is 0.4496 and 0.6888 respectively. This demonstrated that the adaption ability of Adiantum reniforme L.var. sinense Y. X. Lin is very strong.4) The niche overlap, the value is 0.3515, between Adiantum reniforme L.var. sinense Y. X. Linand Iris tectorm is the biggest. It demonstrated that there is strong competition between two for nature resource.The value of the niche overlap with Cyrtomiian fortunei is secondly bigger, it is 0.3389.5) The allzyome variety of Adiantum reniforme L.var. sinense Y. X. Lin : there are 7 polymorphic loci in the 14 loci of 6 kinds of enzymes system tested. The meaning number of the allele gene is compatively low for each locus, the value is from 1.43-1.57, the meaning number is 1.51; the change of the allele frequency is big in different loci, and the value is close to the low side, the percent of polymorphic locus is low and the value is from 0.3571 to 0.5. the mean expected heterozygosity is variged from 0.177 to 0.284. The observed heterozygosity is from 0.194 to 0.284. It shows the genetic variety of Adiantum reniforme L.var. sinense Y. X. Lin is low comparatively.6) The outcrossing rate of Adiantum reniforme L.var. sinense Y. X. Lin is high, the value is from 0.000-3.500. The different locus outcrossing rate of Adiantum reniforme L.var sinese Y. X. Lin has great change in the same population, and the outcrossing rate difference of the same enzyme locus is also high in the different population. It demonstrates Adiantum reniforme L.var. sinense Y. X. Lin is a mixed mating system and the intergametophzyme outcrossing among perhaps plays a main role.7) The result of Spatial autocorrelation study showed: m更多还原