杜鹃花属粉红爆杖花自然杂交与生态适应研究

	杜鹃花属粉红爆杖花自然杂交与生态适应研究
	郑伟
导师	高连明
关键词	杜鹃花属，粉红爆杖花，自然杂交，进化，生态位分化 Rhododendron, R. × duclouxii, natural hybridization, evolution, niche differentiation
摘要	物种形成与适应性进化是进化生物学领域研究的核心问题之一，而自然杂交是物种形成的一个重要途径，在植物进化中起着重要作用，研究自然杂交有助于深入理解杂交物种形成过程和适应性进化等科学问题。本研究以滇中分布的自然杂种粉红爆杖花及其亲本种爆杖花和碎米花为研究对象，通过对多个杂交区进行广泛采样，综合运用简化基因组测序、叶绿体基因sanger测序、形态性状比较、生态位模拟分析以及样方调查等多种手段研究粉红爆杖花与亲本种爆杖花和碎米花不同杂交区的遗传结构与组成、表型分化与生态位分化式样，从而探究粉红爆杖花自然杂交与生态适应机制，以期揭示杂交物种形成的过程并探讨未来可能的演化方向。利用遗传和形态数据揭示了一个包含三个亲本种和两个杂种的自然杂交区的杂种来源与遗传结构。主要结果与结论如下： 1) 粉红爆杖花与其亲本物种的生态位分化基于粉红爆杖花及其亲本种爆杖花和碎米花的空间生态位分析表明，粉红爆杖花分布于爆杖花与碎米花分布区的重叠区域，与亲本种共存，没有形成特有的分布区。粉红爆杖花分布点的气候特征与爆杖花和碎米花均相近，空间生态位重叠程度较大，但发生了一定程度的分化。基于4个粉红爆杖花杂交区的群落组成、物种数量与土壤性质等数据的微生境分化结果显示，粉红爆杖花通常与爆杖花和碎米花共存，且样方中爆杖花和碎米花个体数量较多，粉红爆杖花还未形成特有的生态位；爆杖花与碎米花的群落乔木物种组成与数量存在明显的差异，但粉红爆杖花与两个亲本种间差异较小，更加倾向于某一个亲本种；粉红爆杖花与亲本种的土壤偏好性存在一定程度的差异，特别是与碎米花的分化程度更高；粉红爆杖花和两个亲本种在花和叶的功能性状上存在明显分化。粉红爆杖花与两个亲本种生态位分化的程度不足以促进其杂交物种形成，反而可能由于持续的基因流而形成长期存在的杂交群。 2) 杂种和亲本种在不同杂交区的遗传结构与表型分化基于简化基因组数据、叶绿体DNA序列和表型性状数据对粉红爆杖花7个自然杂交区的杂交起源与过程、遗传结构、表型分化、杂交影响因素及命运进行了综合研究。结果表明，粉红爆杖花由爆杖花与碎米花杂交产生，杂交为双向且不对称的，F1代个体的花性状与碎米花更相近。多重证据分析表明，粉红爆杖花在不同杂交区是多次独立起源的，不同杂交区内的亲本种独立杂交形成大量杂交群，杂交区之间基因流弱，呈现出明显的地理格局，整体上表现为马赛克杂交区的模式。不同杂交区的粉红爆杖花在遗传和性状上整体相似，但其世代类型与组成、杂交来源、遗传组成和性状表型分化式样等存在差异。整体上，F1代个体与F2代个体在表型性状与遗传变异上不存在明显差异，F2代个体的变异幅度较F1代个体更大。通过对不同杂交区和不同类别杂交后代比较分析结果表明，多种因素影响了自然杂交的进程，如亲本遗传组成与数量比例、杂交发生的时间长短、环境选择、人为干扰等。本研究的结果支持粉红爆杖花可能会与两个亲本种形成长期存在的复杂杂交群，而难以形成新的杂交种；不同杂交区可能会有不同的进化方向，受多种因素影响。 3) 粉红爆杖花复杂杂交区的遗传结构与新杂种的界定本研究在楚雄州南华县沙桥镇发现了一个由三个亲本种和两个杂种组成的杂交区，基于遗传和表型数据对杂交区的遗传结构和新杂种的来源进行了研究。结果表明，基于简化基因组的遗传聚类结果与表型性状的聚类结果基本一致，推测的新杂种是由爆杖花和糙叶杜鹃杂交产生的，其表型和遗传都介于两个亲本种之间，主要由F1代和F2代个体组成，且F2代个体占比较高，无回交后代。该杂交区是包含了爆杖花、碎米花、糙叶杜鹃三个亲本种及粉红爆杖花、新杂种五个类群的复杂杂交区，杂交区遗传结构复杂。新的杂种在形态上与粉红爆杖花相似，仅在叶片宽度和花柄长上存在明显差异；两者在遗传组成与子代结构上存在明显差异。该杂交区为进一步开展杜鹃花属杂交物种形成与适应性进化研究提供良好的体系。; Speciation and adaptive evolution are part of the key issues in the field of evolutionary biology. The study of natural hybridization can facilitate our understanding of the process of speciation and the potential adaptive mechanisms of evolution. This study focuses on the natural hybrid Rhododendron × duclouxii distributed in central Yunnan and its parental species R. spinuliferum and R. spiciferum. Here, the population genetic structure, morphological traits, and ecological niche differentiation of these taxa were evaluated in different hybrid zones to determine the mechanisms of natural hybridization and plausible future evolutionary pathways. In addition, the genetic (based on ddRAD and cpDNA sequences) and the morphological data were also used to study the origin of hybrids and the genetic structure of a complex hybrid zone which includes three parental species and two hybrids of Rhododendron. The main results and conclusions of this study were as follows: 1) Niche differentiation between R. × duclouxii and its parents Based on the spatial niche differentiation analysis of R. × duclouxii and its parental species, R. spinuliferum and R. spiciferum, it was found that the distribution of R. × duclouxii overlapped that of the parental species. The climatic characteristics associated with the overall distribution of R. × duclouxii were similar to that of R. spinuliferum and R. spiciferum. However, some differentiation also existed between R. × duclouxii and its parents. The results of the niche differentiation analysis for microhabitats based on community composition data, the number of target species, and the soil properties of plots within the four hybrid zones indicated that R. × duclouxii usually coexisted with R. spinuliferum and R. spiciferum, meaning that R. × duclouxii does not occupy a unique ecological niche, although there was some difference in soil preference between R. × duclouxii and its parental species, especially between R. × duclouxii and R. spiciferum. There were significant differences in the species composition and number between the community of R. spinuliferum and R. spiciferum, but the differences between R. × duclouxii and its parents were small. The functional traits of flowers and leaves were differentiated for R. × duclouxii and its parental species. In summary, niche differentiation between R. × duclouxii and its parental species is not enough to promote the hybrid speciation of R. × duclouxii; instead, it may form a long-term hybrid swarm due to continuous gene flow from parental species. 2) The population genetic structure and phenotypic differentiation of R. × duclouxii in multiple hybrid zones The hybrid origins of R. × duclouxii, the genetic structure of the different hybrid zones, the phenotypic differentiation of other hybrids, the possible factors leading to hybridization and the possibility of hybridization speciation of R. × duclouxii were explored. Based on molecular (ddRAD and cpDNA sequencing) and
语种	中文
	2022-05
学位授予单位	中国科学院大学
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/75138
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	郑伟. 杜鹃花属粉红爆杖花自然杂交与生态适应研究[D]. 中国科学院大学,2022.

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