中国西南山地种子植物多样性演化历史的初步研究

	中国西南山地种子植物多样性演化历史的初步研究
	杨丹
导师	高连明
关键词	生命之树，中国西南山地，演化历史，分化时间估计，多样化速率 Tree of Life, Mountains of Southwest China, Evolutionary History, Divergence Time Estimation, Diversification Rate
摘要	中国西南山地是全球生物多样性热点地区之一，复杂的地质历史和气候变化造就了该地区丰富的物种多样性和特有性，而有关中国西南山地种子植物多样性的区系来源与演化历史尚不清楚。本研究以西南山地种子植物为研究对象，在广泛取样的基础上，基于叶绿体rbcL和matK两个基因重建中国西南山地种子植物的生命之树，利用化石标定和分子钟估算了各节点的分化时间，结合生物区和生物地理学分析研究区域种子植物前五大科和五大属的演化历史，以期揭示中国西南山地种子植物多样性的起源与多样化格局成因。主要结果和结论如下：基于两个叶绿体条形码片段（matK和rbcL）构建了包括15524个种子植物的系统发育树，其中包括西南山地分布的种子植物6294种，占该地区种子植物88%的属和58%的种。系统发育分析结果表明，除少数目的系统位置不同外，其他目级分支的系统发育关系与基于叶绿体基因组结果基本一致，但支持率相对较低；目和科的单系性均得到很好的支持，仅有1个目（山龙眼目）和2个科（伞形科和马兜铃科）的单系性没有得到支持，有84%的属其单系性得到支持。分化时间估算结果表明，中国西南山地种子植物92%的属在第三纪分化形成，其中有482属在中新世之前形成，而780属在中新世之后（23Ma）形成；在中国西南山地物种数前五十的属中，有27属在中新世之前形成，而22属在中新世之后（23Ma）形成。在种级水平上，物种形成数量在中新世之后明显提高，第四纪形成的物种数最多（占所有西南山地种子植物的57%），特有种形成也主要发生在第四纪。分化时间与海拔结合分析结果显示，海拔4000米以下的木本植物随着海拔升高，物种的分化时间较晚，可能因适应高海拔生境而分化成种。中国西南山地种子植物五个大科的物种形成主要发生在中新世之后，以就地物种形成为主；五个大属种多样化形成也以就地物种形成为主，但主要发生在中新世中期或晚期之后，可能因为全球气温下降、横断山造山运动和亚洲季风强化等事件导致生境的异质性增加，促进了该地区物种的就地起源。; Mountains of Southwest China (MSC) is one of the global biodiversity hotspots. The complex geological history and climate change lead to species diversity and endemisms in this region. However, the floristic origin and evolutionary history of seed plant diversity in MSC remain unclear. In this study, we aimed to explore evolutionary history, floristic origin and diversification pattern cause of seed plants in MSC based on two chloroplast genes (rcbL and matK) by reconstructing tree of life, estimating divergence time with fossil calibration with a large-scale sampling, and bioregional and biogeographical analysis of the top five families and genera of seed plants in MSC respectively. Main results and conclusions are as follows: The phylogenetic tree including 15,524 seed plant speices was constructed based on matK and rbcL, out of which 6294 species distributed in MSC, accounting for 88% genera and 58% species of seed plants in MSC. The topology of the phylogeny of seed plants in MSC had basically consistent phylogenetic relationships of orders with those of the plastome genes except for a few orders with weak supported. All the orders and familes were monophyletic excepted for one order (Proteales) and two families (Apiaceae and Aristolochiaceae ), and the monophyly of 84% genera were supported. The results of divergence time estimation showed that 92% genera of the MSC seed plants have been deverged in the Tertiary, among which 482 genera were diverged before the Miocene, and 780 genera formed after the Miocene (23Ma). Among the top 50 genera ordered by species number, 27 genera were formed before the Miocene, and 22 formed after the Miocene (23Ma). At the species level, the number of species diversification increased significantly after the Miocene, with the largest number of speciation in the Quaternary (accounting for 57% of all seed plants in MSC), and the formation of endemic species also mainly occurred in the Quaternary. The correlated analysis of species divergence time associated to elevation showed that woody plants below 4,000 meters above sea level had younger divergence time with the increase of elevation, we infered that the speices in low-altitude likely adapt to high-altitude habitats leading to diverge into new species. The speciation of the top five families of seed plants in MSC mainly occurred after the Miocene, and in-situ speciation was dominant. In-situ speciation was also a dominant way of species diversification in the top five genera in this region, but it mainly occurred after the mid-Miocene or the late-Miocene. The orgion of in-situ speciation in MSC may have likely contributed to the increase of habitat heterogeneity, caused by global temperature cooling, orogeny of Hengduan Mountain and intensification of Asian monsoon in the Neogene.
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/151853/75195
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	杨丹. 中国西南山地种子植物多样性演化历史的初步研究[D]. 中国科学院大学,2022.

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