中国黄、东海马尾藻属(Sargassum)的分类学修订

	中国黄、东海马尾藻属(Sargassum)的分类学修订
	黄超华1,2
学位类型	硕士
导师	孙忠民副研究员
	2017-05-22
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	海洋生物学
关键词	马尾藻属形态系统发育分类修订
摘要	大型褐藻马尾藻属（Sargassum）海藻，主要分布于印度—西太平洋海区，是暖海生态系统的重要组成部分之一。马尾藻属传统分类所依据的形态特征随生长环境和发育阶段等的不同而发生变化，仅通过形态上的差异很难对其进行准确分类。近年来国外学者利用分子标记对马尾藻属进行分类学修订，发现了多个分类学错误和很多同物异名。利用分子标记对我国的马尾藻属的物种多样性研究尚未实质性开展。本研究依据近几年野外调查采集到的马尾藻属标本及中国科学院海洋研究所海洋生物标本馆馆藏标本作为研究材料，利用形态学和分子系统学相结合的方法，对马尾藻属进行分类学修订，理清我国黄、东海马尾藻属的物种组成和分布规律。本研究主要对中国黄、东海的马尾藻属进行整理研究，参考原始记载和对比模式标本，确认了反曲叶亚属7种，包括海蒿子Sargassum confusum、羊栖菜S. fusiforme、半叶马尾藻中国变种S. hemiphyllum var. chinense、铜藻S. horneri、海黍子S. muticum、裂叶马尾藻S. siliquastrum和鼠尾藻S. thunbergii，并对它们进行了详细的形态描述。发现黄、东海原来记载的真马尾藻亚属中的瓦氏马尾藻S. vachellianum、山东马尾藻S. shandongense和青岛马尾藻S. qingdaoense的形态差异很小，是一个形态特征呈连续的分类群（taxon）。利用核糖体DNA内转录间隔区序列2（ITS-2），线粒体细胞色素氧化酶亚基Ⅲ序列（cox3），以及叶绿体核酮糖1，5二磷酸核酮糖羧化酶的大亚基基因（rbcL）三个分子标记，结合NCBI数据库序列信息构建系统发育树，对黄、东海的马尾藻属进行分子系统学研究。确认了7种反曲叶亚属马尾藻的存在，且和韩国的马尾藻属亲缘关系最近。发现真马尾藻亚属中的山东马尾藻、青岛马尾藻和瓦氏马尾藻在三个分子标记都几乎没有碱基差异，因此判断它们为同物异名。山东马尾藻和青岛马尾藻是瓦氏马尾藻的北方地理种群，生长环境的不同导致各个种群间微小的形态差异。此外，结合南中国海和日本的标本进行分子系统学研究，结果表明传统分类体系叶枝亚属（Phyllotrichia）中的球囊马尾藻S. piluliferum应当属于新分类体系真马尾藻亚属（Sargassum）中的真马尾藻组S. sect. Sargassum，反曲叶亚属（Bactrophycus）中的莫氏马尾藻S. mcclurei和凹顶马尾藻S. emarginatum属于真马尾藻亚属（Sargassum）中的冬青叶组S. sect. Ilicifolia。在本次调查研究中，发现我国黄、东海马尾藻属的分布面积显著减少，过去在黄、东海报道过的头状马尾藻Sargassum capitatum，无肋马尾藻 S. fulvellum，草叶马尾藻S. graminifolium，黑叶马尾藻S. nigrifolioides，展枝马尾藻S. patens，任氏马尾藻S. ringgoldianum，锯齿马尾藻 S. serratifolium可能已经消失。人类活动可能是马尾藻属生物量下降，多样性降低的主要原因。关键词：马尾藻属，形态，系统发育，分类修订
其他摘要	Sargassum C. Agardh is the most diverse genus in Phaeophyceae, and particularly abundant in tropical and subtropical regions and the Indo-Pacific. These morphological criteria used by traditional classification system can be highly variable due to environmental conditions or the developmental stage of the thallus. It is very hard to identify species only based on the morphological variability. Foreign phycologists have been carried out molecular markers revision of Sargassum and proposed a few taxonomic synonymies recently. The species diversity of the genus in the China Seas has not yet been revaluated based on integrative molecular evidence. Therefore, in the present proposal, we will carry out a taxonomic revision on Sargassum using the specimens in the filed survey recently and those deposited in the Marine Biological Museum of the Chinese Academy of Science (MBMCAS), with a combination of morphological and phylogenetic analyses. The main aim of this study is to correct the incongruities of traditional classification and reassess the status of specie and to clarify the distribution of Sargassum in the Yellow Sea and the East China Sea. Based on the morphological comparison of type specimens and the original diagnosis, in the subgenus Bactrophycus, we confirmed the presence of at least seven species occurring in the Yellow Sea and the East China Sea, including: Sargassum confusum, S. fusiforme, S. hemiphyllum var. chinense, S. horneri, S. muticum, S. siliquastrum, and S. thunbergii. As to S. subgen. Sargassum, only one morphological taxon spanning arrange of morphological continuum were recognized, which made it difficult to assign a species name as three previously described species: S. shandongense Tseng, C. F. Zhang et Lu, S. qingdaoense Tseng et Lu, and S. vachellianum Greville. Furthermore, the nuclear internal transcribed spacer 2 (ITS-2), mitochondrial cytochrome oxidase subunit Ⅲ (cox3) and the large subunit gene of chloroplast ribulose 1, 5-diphosphate ribulose carboxylase (rbcL) were used to assess the taxonomic relationships and classification of Sargassum in the Yellow Sea and the East China Sea. The results indicated that the sequences were nearly identical among three species of S. shandongense, S. qingdaoense and S. vachellianum. Therefore, we proposed that S. shandongense and S. qingdaoense were taxonomic synonyms of S. vachellianum. It also should be considered that the previously decribed S. shandongense and S. qingdaoense are the geographical populations of S. vachellianum, and the subtle morphological variations among populations detected probably resulted from different environmental conditions. In addition, the result of molecular phylogenetic analysis combing the specimens collected from the South China Sea and Japan suggested that S. piluliferum in the subgenus Phyllotrichia should be in the Section Sargassum (belonging to subgenus Sargassum), and S. mcclurei and S. emarginatum in the subgenus Bactrophycus should be in the Section Ilicifolia. In the study, we found that the distribution area of Sargassum in the Yellow Sea and the East China Sea was significantly shrunk, and several species previously recorded in the Yellow Sea and the East China Sea might be disappeared, including: Sargassum capitatum, S. fulvellum, S. graminifolium, S. nigrifolioides, S. patens, S. ringgoldianum and S. serratifolium. It suggests that human activities may be the main reason for the drop in the biomass of Sargassum and the decrease of diversity. Key words: Sargassum, Morphology, Phylogeny, Taxonomic revision
学科领域	海洋生物学
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/136640
专题	海洋生物分类与系统演化实验室
作者单位	1.中国科学院海洋研究所 2.中国科学院大学
第一作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	黄超华. 中国黄、东海马尾藻属(Sargassum)的分类学修订[D]. 北京. 中国科学院大学,2017.

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