藻苔纲Takakiopsida,一个独特的苔藓植物类群  

Takakiopsida, a unique taxon of bryophytes

作　　者：贾渝[1] 吴鹏程[1] 汪楣芝[1] 何思 

机构地区：[1]中国科学院植物研究所,北京100093 [2]美国密苏里植物园

出　　处：《植物分类学报》2003年第4期350-361,共12页Acta Phytotaxonomica Sinica

基　　金：中国科学院知识创新工程重大项目 (KSCX2_1_0 6B) ;国家自然科学基金重大项目 ( 3 989940 0 ) ;2 0 0 1年中国科学院生物学与生物技术研究特别支持费资助~~

摘　　要：藻苔属Takakia在建立之初被认为是原始的苔类植物。这一神秘类群的出现引起了苔藓学家的兴趣 ,发表了一系列相关的论文。但是随着其孢子体的发现 ,它的系统位置引起了争论。本文详细分析了藻苔属植物的形态性状特征 ,参考了大量其他学科的研究成果 ,认为它既不能归于藓类 ,也不能归于苔类。就其系统位置而言 ,应该成为一独立的纲———藻苔纲。The genus Takakia was established by Hattori and Inoue in 1958 when the gametophyte of T. lepidozioides. was found in Japan. In 1963, a species described by Mitten in the hepaticae genus Lepidozia, L. ceratophylla, was transferred to this genus by Grolle. Since its establishment, this enigmatic genus of two species has been the subject of intense scrutiny and phylogenetic debate, and many papers dealing with its taxonomy, morphology and phylogeography have been published. In this paper we discuss the morphological characters of this genus in detail and analyze much information from spore morphology, cytology, phytochemistry, molecular systematics, phylogeography and paleobotany in order to have a better understanding on its systematic position. Gross-morphologically the sporophytes of Takakia are similar to those of some moss groups such as Andreaea and Andreaeobryum, but the gametophytes are very similar to those of some liverworts, e. g. Haplomitrium and Blepharostoma. Evidence from sporophyte development and antheridial ontogeny indicates that Takakia is neither a moss nor a liverwort. Cytological data indicate its two species is not of very close relationship. Phytochemical data, although very limited, suggest a closer affinity of Takakia to hepaticae than to mosses. There is no exact counterparts in gross sporophyte morphology with Takakia among extant archegoniates, although striking parallels are evident in ancient fossil land plants. The shape and spiralled external architecture of the stem and sporangium of Tortilicaulis, a lower Devonian plant, are remarkably similar to that of Takakia. Takakia as a primitive genus is undoubtedly a unique type, which is systematically isolated in the bryophytes, and has both characters of mosses and liverworts. From these facts we consider that Takakia might have contained more than two species in history, but only two of them have survived. In the long historical geological period, two diverse types, one including liverworts and the other including mosses, might be der

关 键 词：藻苔纲 系统学 苔藓植物 形态特性 

分 类 号：Q949[生物学—植物学]