Biosystematics of Sino-Japanese pteridophytes

1. Matteuccia intermedia被认为是杂种起源，是了解Onocleoid蕨类植物进化的关键种。通过对叶轴上气托和凹槽的形态学比较、细胞学观察和酶电泳分析，表明该种为一独立种，与红豆草（Onoclea orientalis）亲缘关系较近.对云南90种蕨类植物进行了细胞分类学研究。他们首次记录了裸蕨属（Gymnogrammitis）（x=36）和Sorolepidivm（x=c. 35），并证实了迄今报道的中国大部分属的基数。细胞地理学研究表明，中国蕨类植物植物群比日本蕨类植物更具有多样性和祖先性。我们的研究结果还表明，三倍体与无性孢子生殖之间有很强的相关性，这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。至少有两个倒位和延长的反向重复假定占的差异。(2)rbcL基因推导的氨基酸序列的最大似然分析表明，一直被认为是裸子植物的葡萄孢属与其它蕨类植物聚为一个单系群，其中最近的亲缘关系是薇菜属;蕨类植物与种子植物聚为一个单系群，蕨类植物与蕨类植物不属于一个单系群。(3)rbcL gne研究结果表明，现存裸子植物是单系的，而不是并系的，买麻藤属和百脉根属在买麻藤纲中彼此的亲缘关系比与麻黄的亲缘关系更近。

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.