基于孢子形态和分子证据探讨鳞盖蕨属(碗蕨科)系统分类

Phylogeny and Systematics of the Genus Microlepia(Dennstaedtiaceae) based on Palynology and Molecular Evidence

孢粉学是解决植物分类中疑难类群物种微形态分化的重要方法,随着分子系统学的发展,结合这两门学科的优势可以更加有效地解决疑难类群的分类学问题.鳞盖蕨属(Microlepia)是一个分类困难的疑难类群,采用孢粉学与分子系统学一一对应的方法,以及居群取样方式,选取280份样本,联合4个叶绿体片段(rbcL、trnL-F、psbA-trnH和rps4),采用最大似然法和贝叶斯法构建该属的系统发生关系,在此基础上对凭证标本中100份材料的孢子进行观察和分析.综合分子系统学和孢粉学的研究结果,得出结论;(1)在形态学研究中广泛被接受的15个物种得到了单系支持,并厘清了分类困难的复合群;(2)发现边缘鳞盖蕨(M.marginata)可能存在隐性种;(3)建议恢复过去归并处理为异名的瑶山鳞盖蕨(M.yaoshanica)、罗浮鳞盖蕨(M.Iofoushanensis)、四川鳞盖蕨(M.szechuanica)以及滇西鳞盖蕨(M.subspeluncae);(4)提出鳞盖蕨属可能存在杂交现象;(5)提出鳞盖蕨属完整的属下分类建议.

Palynology is an important method to solve the micro-morphological differentiation of species in some complex groups. With the development of molecular phylogeny, combining the advantages of these two subjects may effectively solve the taxonomic issues in plants. Microlepia(Dennstaedtiaceae) is one of the most difficult genera in ferns in terms of taxonomy. In the present study, based on palynology matched with phylogeny and population sampling, we constructed the phylogeny of 280 samples by using both Maximum Likelihood and Bayesian methods with four plastid markers(rbcL, trn L-F, psbA-trnH and rps4). The spore morphology of 100 samples was observed and analyzed. Our results of comprehensive molecular phylogeny and palynology showed that(1) 15 species widely accepted based on plant morphology were strongly supported, and this complex group of Microlepia has been further clarified;(2) There may be crytic species in the populations of M. marginata;(3) M. yaoshanica Ching, M. lofoushanensis Ching, M. szechuanica Ching and M. subspeluncae Ching, treated as synonyms in previous studies, should be restored as independent species;(4) Many hybridization events of Microlepia were found; and(5) A complete infrageneric taxonomy of Microlepia was proposed.