Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, and Laboratory of Systematic & Evolutionary Botany and Biodiversity, College of Life Sciences, Zhejiang University, Hangzhou 310058, ChinaDepartment of Organismic Biology, Salzburg University, A-5020 Salzburg, AustriaDivision of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto 6068502, JapanDepartment of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato, Tsukuba, Ibaraki 305-8687, JapanField Centre for Sustainable Agriculture and Forestry, Faculty of Agriculture, Niigata University, 94-2 Koda, Sado, Niigata 952-2206, Japan.
New Phytol. 2012 Oct;196(2):617-630. doi: 10.1111/j.1469-8137.2012.04242.x. Epub 2012 Jul 27.
East Asia's temperate deciduous forests served as sanctuary for Tertiary relict trees, but their ages and response to past climate change remain largely unknown. To address this issue, we elucidated the evolutionary and population demographic history of Cercdiphyllum, comprising species in China/Japan (Cercdiphyllum japonicum) and central Japan (Cercdiphyllum magnificum). Fifty-three populations were genotyped using chloroplast and ribosomal DNA sequences and microsatellite loci to assess molecular structure and diversity in relation to past (Last Glacial Maximum) and present distributions based on ecological niche modelling. Late Tertiary climate cooling was reflected in a relatively recent speciation event, dated at the Mio-/Pliocene boundary. During glacials, the warm-temperate C. japonicum experienced massive habitat losses in some areas (north-central China/north Japan) but increases in others (southwest/-east China, East China Sea landbridge, south Japan). In China, the Sichuan Basin and/or the middle-Yangtze were source areas of postglacial northward recolonization; in Japan, this may have been facilitated through introgressive hybridization with the cool-temperate C. magnificum. Our findings challenge the notion of relative evolutionary and demographic stability of Tertiary relict trees, and may serve as a guideline for assessing the impact of Neogene climate change on the evolution and distribution of East Asian temperate plants.
东亚的温带落叶林曾是第三纪孑遗树种的避难所，但它们的年龄和对过去气候变化的响应在很大程度上仍不清楚。为了解决这个问题，我们阐明了中国/日本（紫堇属日本紫堇）和日本中部（紫堇属壮丽紫堇）物种的进化和种群历史。使用叶绿体和核糖体 DNA 序列和微卫星标记对 53 个种群进行了基因分型，以评估与过去（末次冰期最大值）和现在的分布有关的分子结构和多样性，这是基于生态位模型进行的。第三纪晚期气候变冷反映在一个相对较新的物种形成事件中，该事件发生在中新世/上新世边界。在冰期，温暖温带的 C. japonicum 在一些地区（中国中北部/日本北部）经历了大规模的栖息地丧失，但在其他地区（中国西南部/东部、东海陆桥、日本南部）却有所增加。在中国，四川盆地和/或长江中游可能是冰后期向北再殖民的源区；在日本，这可能是通过与冷温带的 C. magnificum 进行渐渗杂交而实现的。我们的研究结果挑战了第三纪孑遗树种相对进化和种群动态稳定的观念，并可能为评估新生代气候变化对东亚温带植物进化和分布的影响提供指导。
