【作者】 李伟；

【导师】 郑勇奇；

【作者基本信息】 中国林业科学研究院 ， 林木遗传育种， 2013， 博士

【摘要】 皂荚（Gleditsia sinensis）是我国特有的乡土树种，具有较高的经济和生态价值；在全国范围内呈连续的星点状分布，资源分散，由于其长期的过度利用，天然林资源已遭到严重的破坏，种内遗传多样性保存面临严峻的挑战。对我国南方现有皂荚遗传资源进行收集、保存及遗传多样性测定评价，为科学合理的皂荚遗传资源保护、筛选优异种质和经济价值开发奠定坚实基础。本研究在我国南方的皂荚主要分布区抽取10个群体215个个体，采集荚果以及叶片进行遗传多样性分析、并对种子进行打破休眠处理、播种育苗试验以及果实化学成分测定，依据研究结果制定皂荚遗传资源的保护策略、构建保护机制，为皂荚种质保存及高效、综合利用开发这一宝贵植物资源提供理论指导。主要研究结果如下：1.皂荚果实、种子等性状在群体间和群体内存在丰富的变异，11个性状在群体间、群体内均达显著差异，11个性状的平均表型分化系数为20.42%，群体内的变异大于群体间的变异，群体内的变异是皂荚的主要变异来源；皂荚各性状平均变异系数为11.20%，变异幅度为4.55%-18.38%。群体间荚果的变异（14.75%）高于群体间种子变异（6.95%），表明种子变异稳定性高。荚果和种子各性状之间多呈极显著或显著正相关，表现为荚果越大，则种子越大，种子的千粒重也越大；在地理变异方面，荚果表现为同地理经度的南北变异，种子则表现为同地理纬度的东西变异。2.利用筛选出的14对荧光引物，对10个群体215个个体进行AFLP分子标记分析，共得到1782条带，其中多态性片段为1389条，平均多态位点百分率为77.94%。AFLP分子标记揭示了基因频率在群体间差异显著，进而在DNA水平上揭示了群体的遗传差异；皂荚不同群体的遗传多样性存在极显著差异（P<0.01），群体间的遗传分化系数（Gst）为26.87%，群体内的变异远大于群体间的变异，群体内的变异是皂荚的主要变异来源。皂荚群体平均有效等位基因数Ne、等位基因数Na、Shannon’s信息指数和Nei’s多样性指数分为1.261、1.714、0.256和0.168。皂荚基因流（Nm）为1.483，10个群体的平均遗传一致度和遗传距离分别为0.950和0.059，说明皂荚群体间存在着一定的遗传分化。贵州兴义群体的遗传多样性最高，广西桂林群体的遗传多样性最低。3.不同群体间皂荚果壳和种子的化学成分存在差异，在种子化学成分中，广西桂林群体皂甙、粗蛋白和粗淀粉的含量最高，分别为8.13%、22.87%和36.91%，湖北京山群体总糖的含量最高，为16.36%；果壳化学成分中，重庆秀山群体粗蛋白的含量最高，为4.41%，贵州兴义群体粗脂肪的含量最高为8.07%，甘肃天水群体果胶的含量最高，为0.71%湖南城步群体总糖含量最高为34.76%；山东费县群体皂甙的含量最高为18.33%。对不同群体皂荚全果有效成分的分析比较，为以后的良种选择，高效、综合利用开发这一宝贵植物资源提供了重要理论依据。4.浓硫酸可以打破皂荚种子休眠，经浓硫酸处理2个小时后，种子发芽率为95.70%，比对照提高了88.00%；破壳处理使皂荚种子的平均发芽时间缩短了近17天，发芽率提高了近11倍，浓硫酸浸泡2小时后，在25℃下皂荚发芽率和发芽势最高，分别为95.70%和85.40%。5.皂荚各群体内家系子代幼苗的苗高和地径都存在丰富变异，苗高和地径在群体间、群体内家系间的差异均达到极显著水平。各家系的子代幼苗生长方面存在较大差异，苗高的变异系数在19.45%-34.15%之间，平均为26.07%；地径变异系数在10.35%-21.38%之间，平均为15.09%。皂荚群体苗高生长与产地纬度和年平均温度呈显著负相关，表现出明显的纬向渐变型。6.皂荚遗传资源流失严重，群体处于濒危状态，遗传资源保存应该注意加强现有其遗传资源的保护，避免基因资源进一步流失，针对性开展遗传资源的原地保存和异地保存，并在其分布区内严格按照样本策略收集群体样本，营建皂荚遗传资源收集圃，建立种源/家系试验林，构建种子库开展设施保存，同时还可借助植物园的优势开展资源保存工作；在遗传改良工作中，遗传改良与保存相结合，收集保存丰富的变异材料，为育种工作提供充足的资源，从而为皂荚的可持续利用奠定基础。更多还原

【Abstract】 Gleditsia sinensis, a unique native species of China with high economic and ecologicalvalues; is distributed continuously as scattered individual trees, particularly around villages. Atpresent, the natural resources of Gleditsia sinensis are being severely damaged because oflong-term over-exploitation, which also contributes to the loss of genetic diversity. In thepresentstudy, wild resources of Gleditsia sinensis in the southChina were investigated; thegenetic diversities were evaluated andthese results established basis foundation for theGleditsia sinensis resources protection, the genetic improvement and the screening of superiorgermplasms rationally and scientifically. Moreover, it is also provided the basement forexploiting the economic value of Gleditsia sinensis resources and its industrialized productionas the “forest-medicine” pattern in a large-scale area. Based on the multitudinous conservationmodel, the theory of field investigation, and natural distributionof scattered trees,215individuals with10populations of Gleditsia sinensis in the southern part of China wereconllected. The morphological diversity, the DNA diversity, the breaking dormancy of seed, theprogeny seedling growth traits, and the chemical constituents were studied. At the same time,out research provided the conservation strategy for genetic diversity of Gleditsia sinensis andconstructed conserving forests in different regions with more plots. The resultsare shown asfollows:1. The analysis of variances of all traits showed significant differences among/withinpopulations. The mean values of phenotypic differentiation coefficient for the eleven traitswere20.42%, and the variation within populations (70.58%) was higher than that amongpopulations (20.42%), which indicated that the variance within population was the main part ofthe phenotypic variation of the species. The variation ranges of CV among11traits were4.55%and18.38%, and the average was11.20%. The CV of pod within populations (14.75%) washigher than seed (6.95%)，which means that the seed has high stability. Most of the pod and seed traits were positively correlated. The seed was proved a west-east variation at samelatitude. The pod was proved a west-east variation at same longitude.2. The AFLP system was built and used for the amplification reaction in the experiment.There were totally219individuals which were selected and analyzed by amplification using14pairs of AFLP primers screed1782bands were obtained and1389bands (77.94%) of themwere found to be polymorphic. The difference of frequency reflected the difference of geneticstructure. The genetic differentiation coefficient amonge10populations (Gst) was26.87%, andthe variation within populations (73.13%) was higher than that among populations (26.87%)These results indicated that the variance within population was the main part of the variation ofthe species. As for genetic diversity parameter, the average effective number of alleles is1.261.The average number of alleles was1.714. Shannon’s information index is0.256and that ofNei’s is0.168. The gene flow (Nm) was1.483. The average genetic identities and geneticdistance were0.950and0.059, respectively. These results indicated that a certain degrees ofgenetic differentiation exist amonge the populations. Gui Zhou Xing Yin population was thehighest diversity and Guang Xi Gui Lin was the lowest diversity.3. There are differences between populations for chemical constituents. In the podchemical constituent, the average content of saponins, crude protein, and crude starch is thehighest in Guangxi population is8.13%,22.87%,36.91%respectively. The average of totalsugar in Hubei Jingshan population is the highest is16.36%. In the seed chemical constituents,the average content of crude protein is the higtest in Chongqing Xiushan populations is4.41%;the average content of crude fat is the higtest in Guizhou Xingyi populations is8.07%; theaverage content of pectin is the higtest in Gansu Tianshui populations is0.71%;the averagecontent of total suggeris the higtest in Hunan populations is34.76%The average content ofsaponins in Shandong Feixian is18.33%, which is the highest in all pupulations. Analysis theChemical constituents of seed and pod can provide an important theoretical basis for theselection of superior cultivars, efficient and comprehensive utilization of the development ofthis valuable plant resource. 4．The seed dormancy of Gleditsia sinensis could be broken through corrosion with highconcentrated H2SO4. The seed was95.70%, which was increased by88.00%than control afertreatment by concentrated H2SO4for two hours. The17days’ decrease in mean germinationdays and11fold’s increse in coefficient of germination speed after breaking skin. After treatedby sulphuric acid for120min, the optimum germination temperature was25℃, thegermination rate and germination power were95.70%and85.40%, respectively.5. The analysis of variance showed that there are significant differences between opulationand families within population for growth traits. There were differences of the growth traitsamong each family. The height ranges of CV among the populations were19.45%and34.15%,and the average was26.07%. The diameter s at ground range of CV among the populationswere10.35%and21.38%, and the average was15.09%. A significant negative correlation wasfound between the height growth and the latitude.6. Gleditsia sinensis genetic resource conservation programe should pay attention for theprotection of existing natural forest, forbiding logging reserved forests, while protecting theirhabitats. Sampling of seeds (or propagation materials) from more populations with a smallernumber of trees at each site is preferable except for in situ conservation. Conservationstands/gene banks, provenance/families trials, clone banks and seed banks shoud be established.While some botanical gardens and arboretums are also proposed to conserve the geneticresources of the species. The individual number of populations should be increased while thepopulations should be induced. The selection of good varieties should be taken seriously. It isparticularly important to protect the integrity of a population while the conservation.更多还原