中国红藻门红毛菜属(Bangia)系统分类学研究

The species of Bangia are newly cultivated seaweeds in China, which have high nutrition with great commercial importance. However, the species and distribution of Bangia in China had still not been understood clearly, and the relationship of Bangia originated in freshwater and seawater is unknown yet. It is very necessary to make effort on the cytological and molecular taxonomy of Bangia. In present project, we will look up the key vouchers specimen and references. The sampling sites of the freshwater of Mid-Western and sub-tidal areas in the coastal of China will be selected in order to collect the live samples and vouchers specimen.The specimen will be identified by morphological, anatomical, and ecological criteria according to modern species concepts in the Bangiales. The live samples will be cultivated and amplified in the laboratory to observe their life cycles. The live conchocelis and prothullus of Bangia which are cultivated will be fixed, and the chromosome numbers and the karyotype characters will be checked. The molecular systematic studies will be carried out based on the sequence analysis of ribosome gene clusters of nuclear genome and rubisco large subunit gene of plastid genome, according to which the phylogentic tree will be built. The results of the morphological, cytological and molecular systematic data will ascertain the taxonomy characters and relationships of Bangia in China.

红毛菜具有较高的经济价值，是新兴的重要栽培红藻，然而目前对我国红毛菜属植物的种类、分布；淡水与海水红毛菜的亲缘关系等研究不足，需要从细胞学和分子系统学角度进行深入探讨。本课题在查阅标本及文献记录的基础上，在我国中西部地区淡水水系和东部沿海地区选点，进行红藻门红毛菜属野外考察及标本（样品）采集，获得活体材料和压制标本。活体材料带回实验室进行培养，观察生活史过程。观察培养的红毛菜原叶体和丝状体进行细胞核分裂过程，并比较近缘种类的染色体数目、核型特征。在各个物种的样品进行核糖体基因簇、rbcL和IGS基因进行序列分析的基础上，开展分子系统学研究，构建系统进化树。结合上述形态分类学、细胞分类学及分子系统发育分析确定我国红毛菜属植物的分类地位和系统演化规律。

本项目通过对分布在中国的红毛菜属类群进行大量的调查、采集、培养，细胞学观察和分子序列研究。结果发现：中国海水红毛菜分布于北起大连南至海南沿海的高潮间带礁岩上，遍布辽宁、山东、江苏、浙江、福建、广东及海南等海湾处；淡水红毛菜主要分布于中西部山间流动溪水或瀑布飞溅的岩石处，如山西娘子关、兰州五泉山、兰州兴隆山。大部分海水红毛菜具有性、无性两种生殖方式，目前仅有大连、青岛海水红毛菜未发现有性生殖；淡水红毛菜仅行无性生殖。不同地区的海水红毛菜与淡水红毛菜染色体均为n=4。在rbcL和nrSSU序列分析中，淡水红毛菜与海水红毛菜的序列同源性差异较明显，在国际红毛菜目分类系统中，中国淡水红毛菜均隶属Bangia属，大部分海水红毛菜聚类在“Bangia” 2，而威海、青岛石老人和青岛胶州湾红毛菜聚类在“Bangia” 1中。通过对红毛菜18S rDNA、5.8S rDNA及ITS区域序列、28S rDNA部分序列和IGS部分序列分析，结果显示：中国淡水红毛菜与世界其他地方的淡水红毛菜分为一支，独立于海水红毛菜；威海的海水红毛菜聚类在“Bangia”1中，其他海水红毛菜聚类在“Bangia”2中。结果与rbcL和nrSSU序列分析的结果一致。此外，通过对中国红毛菜类群的ITS和IGS序列中用于系统分类的分析显示，ITS序列是红毛菜种间分子分类的有效标记，IGS序列是种下鉴定的有效标记。通过项目实施，在国内外杂志发表论文7篇，其中SCI收录4篇，中文核心3篇，完成了项目目标和任务。