【作者】 王昆蕾；

【导师】 干友民；

【作者基本信息】 四川农业大学 ， 草业科学， 2007， 硕士

【摘要】 马蹄金是目前运用较广泛的草坪植物，在我国西南地区有丰富的野生资源，极具开发利用价值。本试验以西南地区收集的23份野生马蹄金种质材料为研究对象，从种群生态、形态学水平、生理特性、DNA水平揭示其遗传多样性，初步探讨了其遗传结构，并以美国进口品种普通马蹄金（Dichondra）为对照从外部形态及抗性方面与野生材料进行比较研究，为进一步筛选马蹄金新品种选育和开发利用奠定基础。研究结果表明：（1）在本调查区域内，野生马蹄金分布于海拔300～1970m间；采集地年均温在14℃～18.1℃，年均相对湿度63％～81％，气候多属于亚热带湿润季风气候。对土壤要求不高，在黄壤、黄红壤、红壤、砖红壤、紫色土等多种土壤类型中都有分布。其分布特征以片状分布为主，在群落中很少以伴生种出现。群落生境可以分为：河滩草地型（田坎、沟边）、山地丘陵型（公路边和山坡）、林地型（树林下）。野生马蹄金材料在10个形态指标上出现较大变异，其中叶长、叶宽、草层高度、叶柄长、分枝数、主茎长以及叶片、匍匐茎颜色的变异都达到20％以上。相关分析表明：随着海拔的增加，马蹄金叶片面积相应增大（0.37-1.35cm²），叶柄增粗（0.47-0.80mm），叶片厚度变小（0.189-0.096mm）。聚类分析结果：23份野生材料可分为4个类群，分别是大叶高丛型、大叶矮丛型、小叶矮丛型、小叶短茎型。（2）对野生马蹄金材料抗病性研究表明，各材料间抗病性差异明显。其中发病率变幅为0.35％～29.84％，变异系数1.534；病斑数变幅0.77～67.1，变异系数为1.615。根据材料的发病情况和严重程度可将野生材料分为3个等级。其中SD200512感病最为严重，其受害程度远远大于其他材料，为高感材料；SD200407为抗病材料，其余材料感病程度界于二者间。（3）对马蹄金抗寒性的观察表明，不同材料越冬率、枯黄期和返青时间有差异，其中四川纳溪SD200310、大邑SD200406、重庆璧山SD200511、云南先锋YD200502、贵州打羊GD200501等地材料具有较好的抗寒性。（4）应用ISSR标记对23份野生马蹄金遗传多样性进行检测，结果表明：14个ISSR引物共产生138条扩增条带，多态性条带131条，多态性条带比率94.9％；扩增条带变幅6～15条，每个多态性引物平均能产生9.36条多态性带。野生马蹄金材料的遗传相似系数（GS）变化范围为0.211～0.871。运用ISSR标记能够揭示西南地区野生马蹄金较大的遗传多样性。基于遗传相似系数的UPGAM聚类分析表明，利用ISSR标记也可将供试材料完全区分开，23份野生马蹄金分为4大类。依据ISSR遗传相似系数（GS）划分的类群同地理分布也有一定关系。（5）根据采集地的生态环境的差异，可将23份马蹄金野生材料分为5个生态地理类群，即成都平原类群、盆周山区类群、川中丘陵类群、云南类群、贵州类群。对马蹄金各地理类群的遗传多样性指数分析表明：川中丘陵群体的遗传距离（GD）值最大，与之对应的衡量该群体多样性的Shannon指数（Ho）和Simpson指数（D）也是最大值。说明川中丘陵的几份材料的遗传多样性水平较其他类群高。对各地理类群而言，物种水平上的表型多样性H_sp=0.6286，而群体水平上的表型多样性H（group）=0.2807，类群内和类群间的表型多样性分别是H_within=0.4465和H_between=0.5535。表明类群内的遗传变异占总变异的44.65％，而类群间的遗传变异占总变异的55.35％，马蹄金野生材料地理类群间的遗传变异大于各地理类群内的遗传变异。（6）马蹄金除11月～2月停止生长外，其余时间均有开花。主要花期集中在4月～6月，7月～9月为结实期。四川地区野生材料中SD200301、SD200302、SD200303、SD200304、SD200310、SD200311均能结实。（7）种子发芽率测定结果表明：结实材料的种子活性有显著差异，其中SD200301、SD200302的种子活力指数最高（45.2），在未经处理的情况下它们的发芽率均达到50％以上。可望在今后进行种子生产，为马蹄金的有性繁殖提供基础。更多还原

【Abstract】 Dichondra repens is one of the widely-use lawn plant. There is abundant native Dichondra repens in the South-west of China, with great potential of utilization. After the research of 23 Dichondra repens germplasm in the south-western of China on their hereditary constitution and diversity. In view of their abundant variation and genitic diversity, systematic studies on different levels had been made on pop-ecology、morphology、physiological and DNA markers. Comparative study on Dichondra repens germplasm from the extra-morph and resistance with the species as check, for screening the excellent strain and strenthen to reserve or utilize Dichondra repens germplasm. The main research fruits went as follows:（1） In this study area, The native Dichondra repens germplasm were distributed at the altitude of 300m～1970m. The sam of year in collection area was 14℃～18.1℃, annum relative humidity was 63%～81%, climate was the subtropical zone moist monsoon climate, and they could grow in lots of types of soil, such as yellow soil、yellow-red soil、red soil、laterite、purple soil, and so on.. The main characteristic of distribution was lamellar and seldem as accompanying species in community. The ecological environment types could be classified into three types: flood grassland type（field candela, ditch side）, mountain hills type（highway, hillside）, wood land type（under the woods）. The native population showed obvious variation in 10 external morphological characters of Dichondra repens, leave length、leave width、herb hight、leafstalk length、arborization numbers、main stem and the color of leaf and creeping stem had the coefficient of variation were over 20%. analysis of correlation showed that with the increasement of altitude, an area of Dichondra repens leaf got larger （0.37-1.35cm²）, leafstalk more thickening （0.47-0.80mm）, thickness of leave got more thin （0.189-0.096mm）. cluster analysis showed that 23 populations could be classfied into 4 groups based on the results of clustering analysis, large leaf and high stock type; large leaf and short stock type; small leaf and short stock type and small leaf and short stem type. （2） The study on disease resistance of Dichondra repens showed that there were obvious difference between each accession, the amplitude of disease incidence was 0.35%～29.84%, coefficient of differentiation was 1.534; the amplitude of the number of disease spots was 0.77～67.1, coefficient of differentiation was 1.615. according to the incidence and serious extent of each accession, all of the accessions could be divided into 3 grade, among the total, SD200512 had the most serious incidence, was the weak disease resistance accession; SD200407 was the strong disease resistance accession, incidence of other between the two accessions.（3） After an observation on cold resistant of Dichondra repens the results showed different accession had differences in hibemalisation rate, time of dry, time of return green. among which SD200310 from NaXi in SiChuan, SD200406 from DaYi, SD200511 from BiShan in ChongQing, YD200502 from xianFeng in YunNan, GD200501 from DaYang in GuiZhou showed better cold resistance..（4） Genetic diversity of 23 native Dichondra repens accessions from south-western China was tested by Using ISSR Maker, the results showed a total of 138 bands were amplified by 14 ISSR primers, among which 131 bands were found to be polymorphic, the percentage of polymorphic bands reached to 94.9%. And consequently a number of stable DNA fragments were produced, ranging from 6 to 15 per primer, with 9.4 polyrnorphic bands per primer on average. The ISSR-based genetic similarity values among 23 Dichondra repens accessions ranged from 0.211 to 0.871. Abundant genetic diversity among Dichondra repens accessions could be revealed by ISSR marker. Analysis of cluster showed that all the 23 accessions could be distinguished by ISSR markers and divided into 4 groups according to UPGMA method. The results also showed that the genetic diversity in Dichondra repens accessions based on ISSR genetic similarity was correlated with geographic distribution to some degree.（5） According to the difference of ecology environment in collecting areas, all the 23 D. repens accessions could be divided into 5 ecogeography groups, including ChengDu plain group, group for Amb-basin mountain area in SiChuan Province, group for hills in the middle of SiChuan Province, YunNan group, GuiZhou group. After the analysis of genetic polymorphism indexes of each geographical groups of D. repens, the results showed the biggest value of GD was group of Amb-basin mountain area in SiChuan, corresponding with the biggest Shannon index and Simpson index. it indicated that the level of genetic diversity in those accessions were greater than other groups. when it come to each geography group, phenotype diversity on species level H_sp=0.6286, but phenotype diversity on group level H_group=0.2807, phenotype diversity on within group and between group were H_within=0.4465 and H_between=0.5535. So the genetic variation of wild D. repens among geography groups （55.35%） was greater than that within geography groups （44.65%）.（6） Dichondra repens blooming in whole of the year except stopping growth in winter. the main blooming date centered on april to June, time of fructification was on July to september. All of the Dichondra repens accessions could be blooming, but there were significant difference in seed-sitting among them. among the SiChuan Dichondr repens accessions of, SD200301、SD200302、SD200303、SD200304、SD200310、SD200311 could be fruited.（7） Studise on seed activity of Dichondra repens accessions from sichuan provence which could be fructification were conducted, and the results showed significant different in seed activity between them. accession SD200301 and SD200302 had the highest value of seed vitality index, and the germination rate could reach over 50% without any treatment which hope to seed produce in the future to base on the study of generative propagation of Dichondra repens.更多还原