中国伞形蜈蚣藻和亚栉状蜈蚣藻的合种研究——基于形态观察、早期发育及分子分析

运用分子辅助的形态分类学方法对分布于我国浙江省温州市南麂岛(模式标本产地)的伞形蜈蚣藻Grateloupia corymbcladia Li et Ding和亚栉状蜈蚣藻G. subpectinata Holmes进行了详细研究。结果表明: (1)伞形蜈蚣藻藻体直立, 紫红色, 软骨质, 高15—30 cm。主枝扁平, 末端延长为亚扁形, 宽2—5 mm。藻体主枝两侧分布有小羽枝和1—2回羽状分枝; 辅助细胞生殖枝丛类型为Grateloupia型(5cpb-4auxb型), 四分孢子囊十字形分裂产生, 以上特征与亚栉状蜈蚣藻一致。(2)在实验室条件下培养亚栉状蜈蚣藻和伞形蜈蚣藻的雌配子体, 观察到二者的孢子发育类型均为“间接盘状体”型。(3)基于rbcL和COⅠ基因序列分析结果显示, 6个伞形蜈蚣藻样本之间无碱基差异, 与亚栉状蜈蚣藻无碱基差异, 形成独立的进化枝。基于以上结果, 确定伞形蜈蚣藻与亚栉状蜈蚣藻为同一种。根据优先法则, 将伞形蜈蚣藻作为亚栉状蜈蚣藻的同物异名。

RESEARCH ON THE COMBINED SPECIES BETWEEN GRATELOUPIA CORYMBCLADIA LI ET DING AND G. SUBPECTINATA HOLMES BASED ON THE MORPHOLOGICAL OBSERVATIONS,EARLY DEVELOPMENT AND MOLECULAR ANALYSES

Grateloupia corymbcladia Li et Ding and G. subpectinata Holmes distributed in Nanji Island, Wenzhou City, Zhejiang Province (specimen of origin) were studied in detail using molecular-assisted alpha taxonomy (MAAT). The results showed that: (1)G. corymbcladia were upright, purple-red, cartilage and 15—30 cm height. The main branch was flat, and the end was elongated to a sub-flat shape with 2—5 mm wide. Branchlets and 1—2 pinnate branches were distributed on both sides of the main branch. The reproductive structure of the female gametophyte included carpogonial branch ampullae and auxiliary cell ampullae, which were composed of five cells and four cells (Grateloupia type), respectively. Mature tetrasporangia originated from inner cortex cells and split into cross. The above characteristics were consistent with G. subpectinata. (2)Under laboratory conditions, the female gametophytes of G. corymbcladia and G. subpectinata both produced and divided to form discoids. The spore development types were all “mediate discal type”. (3)Based on the results of rbcL and COⅠ gene sequence analysis, there were no pairwise divergence between the six samples of G. corymbcladia and the G. subpectinata. They all formed a single monophyletic subclade. These results indicate that G. corymbcladia and G. subpectinata were the same species, and G. corymbcladia was regarded as the synonym of G. subpectinata.