Genome size and plastid trnK-matK markers give new insights into the evolutionary history of the genus <i>Lavandula</i> L.
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The genus <i>Lavandula</i> L. consists of 39 species distributed from the North Atlantic Islands, across the Mediterranean Basin to India. We analysed 36 taxa of the genus <i>Lavandula</i> representing two of the three subgenera and six of the eight sections according to the most recent classification (Upson & Andrews 2004). We achieved a phylogenetic reconstruction from partial sequences from plastid trnK and matK genes, the genome size was estimated by flow cytometer measurements. The primary aim was to track phylogenetic patterns through the maternal inherited marker at the sectional level and identify possible genome duplications. The cpDNA tree shows the phylogenetic relationships between subgenus, sections and also elucidates for the first time the relationships between the endemic species of Macaronesia, Morocco and Arabia. The ancestral split between the two subgenera could be explained by dispersal followed by an early vicariance event. The C-value shows genome up-sizing within several phylogenetic clades and geographical areas. An ancestral genome-up sizing is characterized at the node of section <i>Dentatae</i> and <i>Lavandula</i>. The cpDNA tree suggests the taxa <i>L. angustifolia</i> subsp. <i>pyrenaica</i> (DC.) Guinea and <i>L. stoechas</i> subsp. <i>luiseiri</i> are best treated as a distinct species.
薰衣草属（Lavandula）L.包含39个物种，分布范围自北大西洋群岛经地中海盆地延伸至印度。本研究分析了该属的36个类群，依据最新分类系统（Upson & Andrews 2004），涵盖3个亚属中的2个亚属以及8个组中的6个组。研究通过质体trnK基因与matK基因的部分序列完成系统发育重建，并借助流式细胞术测定估算基因组大小。本研究的核心目的为：通过母系遗传标记追踪组级水平的系统发育模式，并识别潜在的基因组复制事件。叶绿体DNA（cpDNA）系统发育树阐明了亚属、组间的系统发育关系，同时首次揭示了马卡罗尼西亚、摩洛哥及阿拉伯半岛特有物种之间的亲缘关系。两个亚属间的祖先分化事件可通过扩散作用伴随早期隔离分化过程加以解释。C值分析结果显示，多个系统发育分支及地理区域内存在基因组增大现象；在<i>Dentatae</i>组与<i>Lavandula</i>组的节点处，检测到祖先型基因组增大事件。基于cpDNA系统发育树的结果，<i>L. angustifolia</i> subsp. <i>pyrenaica</i> (DC.) Guinea与<i>L. stoechas</i> subsp. <i>luiseiri</i>这两个类群应被处理为独立物种。
