中国和喜马拉雅地区卷柏属异形孢子叶植物的分类修订

The cosmopolitan distributed Selaginella with about 700-750 species, is the largest and the least studied genus of lycophytes. The taxonomy of Selaginella is notoriously difficult, especially for the dimorphic-sporophyll species. There are about 45-55 taxonomically unclear species of this group from China and the Himalayas. Dimorphic-sporophyll species are specialized with dorsi-ventrally compressed strobilus and dimorphic sporophylls. Plants of this group are normally small plants, stem short and slender, leaves smaller and thin. They often grow in humid and shaded forests. Species delimitation in Selaginella is difficult and problematic because the leaf characters are often insignificant. In this study, we will concentrate on the morphological and molecular systematic studies of the dimorphic-sporophyll species and related groups in Selaginella. We will make field population observation and specimen collection, compare and analyze the characters of leaf morphology, foliar epidermis, strobilus, sporangia distribution pattern, sporangium cells and spores. DNA barcoding analyses will be based on ITS, rbcL and some other new markers developed in this study. A comprehensive taxonomic revision of the dimorphic-sprophyll Selaginella from China and Himalaya will be made based on morphology and molecular evidence. The evolutionary history and taxonomic implications of different characters will be discussed, and a suitable set of DNA barcode for fast identification of Selaginella will be explored.

卷柏属是石松类植物最大的属，世界广布，约700-750种；由于形态性状的细微和研究不充分，迄今仍然是石松类最缺乏研究的，特别是孢子叶异形的类群。在中国和喜马拉雅地区分布有45-55个异形孢子叶卷柏物种，其孢子叶穗背腹压扁，植株矮小细弱，叶片小而质地薄，喜生阴暗潮湿的林下；由于分类特征不明显，物种划分问题最多。本研究将基于野外居群调查和标本采集，进行宏观和微观形态学研究，比较和分析叶片形态、叶表皮细胞、孢子叶穗和孢子叶形态、孢子囊分布式样、孢子囊壁细胞和孢子形态及纹饰等方面的证据；并结合细胞核基因ITS和叶绿体基因片段rbcL及本研究新开发的分子标记，解决疑难物种的划分问题，并评估和筛选适用于卷柏物种快速鉴定的DNA条形码。

卷柏属是石松类植物最大的属，世界广布，约700-750种；由于形态性状的细微和研究不充分，迄今仍然是石松类最缺乏研究的，特别是孢子叶异形的类群。在中国和喜马拉雅地区分布有45-55个异形孢子叶卷柏物种，其孢子叶穗背腹压扁，植株矮小细弱，叶片小而质地薄；由于分类特征不明显，物种划分问题最多。本研究基于野外居群调查和标本采集，进行宏观和微观形态学研究，比较和分析叶片形态、孢子叶穗形态、孢子纹饰等方面的证据；并结合本研究新开发的分子标记叶绿体基因片段rbcL，psbA,和atpI的DNA条形码对卷柏属异形孢子叶物种进行了分类修订。本研究发表了 Selaginella subvaginata X.C. Zhang & Shalimov和Selaginella dianzhongensis X.C. Zhang两个新种，同时处理包括Selaginella jugorum，Selaginella shensiensis和Selaginella longistrobilina 等多个分类名称问题。本研究对卷柏属21个物种进行了叶绿体基因组测序，构建了目前卷柏属最稳定的系统发育框架。同时，本研究还对伏地卷柏Selaginella nipponica的叶绿体，线粒体基因组进行了研究，结果发现在伏地卷柏中188-kb的质体基因组的主构象中存在三个核糖体操纵子拷贝，可转换成包含两个近乎等比例存在的110-kb和78-kb的亚基因组构象，该研究揭示了早期陆地植物卷柏中独特的细胞器基因组演化模式及机制，拓展了我们对植物界细胞器基因组演化的认识。