Biosystematics of Sino-Japanese pteridophytes

1.Matteuccia intermedia一直被认为是杂交种，是了解七叶蕨类植物系统发育的关键物种。叶轴上气孔器和沟槽的比较形态、细胞学和酶电泳法表明，该种是一个与东方红豆草亲缘关系密切的独立种。对采自云南西南部中国地区的90种蕨类植物进行了细胞分类研究。他们首次记录了裸盖草属(x=36)和松属(x=c.35)的基本染色体数目，并证实了迄今报道的大多数中国属的基本数目。一项细胞地理学研究表明，中国的蕨类植物区系比日本的更多样化，更具祖先。我们的结果还表明，三倍体与无性孢子之间存在很强的相关性，这一点在其他地区的蕨类植物中也是已知的。对蕨类植物和种子植物的系统发育关系进行了分子系统学研究：(1)铁线蕨叶绿体DNA的基因图谱在基因序列和组织结构上与典型被子植物叶绿体基因组有很大差异。(2)rbcL基因氨基酸序列的最大似然分析表明，已被认为是程序性精子的Botrypus与其他蕨类植物单系聚在一起，其中最近的亲缘关系是紫薇属，蕨类和种子植物是单系聚类，蕨类和苔藓植物不属于一个单系群。(3)rbcL Gne研究的结果表明，现存的裸子植物是单系的，而不是单系的，在Gnetopsida中，Gnetum和Welwitschia彼此之间的亲缘关系更近。

1. Matteuccia intermedia has been considered to be of hybrid origin and is a key species for understanding the phylogeny of onocleoid ferns. Comparative morphology of pneumatophores and grooves on leaf axes, cytology, and enzyme electrophoresis indicate that the species is a distinct species closely related to Onoclea orientalis.2. Cytotaxonomic studies were made for 90 fern species from Yunnan, southwestern China. They recorded for the first time the basic chromosome numbers of Gymnogrammitis (x=36) and Sorolepidivm (x=c. 35), and confirmed the basic numbers reported so far for most Chinese genera. A cytogeographic study sugested that Chinese fern flora is more diverse and ancestral than the Japanese. Our results also showed that there is a strong correlation between triploids and agamospory, as is known for fern in the other regions.3. Molecular systeamtic studies were made to examine the phylogenetic relationships of pteridophytes and seed plants.(1) The gene map of Adiantum capillus-veneris chloroplast DNA much differs from typical angiosperm chloroplast genome in gene order and organization. At least two inversions and elongation of the inverted repeat is postulated to account for the difference.(2) Maximum likelihood analysis of deduced amino acid sequences of rbcL gene indicates that Botrypus, which has been considered as a progymnosperm, clusters monophyletically with the other ferns, in which the closest relative is Osmunda, and that ferns and seed plants cluster monophyletically, and ferns and bryophytes do not belong to a monophyletic group.(3) Results of a rbcL gne study indicate that extant gymnosperms are monophyletic and not paraphyletic, and in Gnetopsida, Gnetum and Welwitschia are more closely related to one another thar either to Ephedra.