缢基蜈蚣藻的修订——基于形态观察、早期发育及分子序列分析

RESEARCH ON THE REVISION OF GRATELOUPIA CONSTRICATA LI ET DING BASED ON MORPHOLOGICAL OBSERVATIONS AND EARLY DEVELOPMENT OF SPORES AND MOLECULAR ANALYSES

  • 摘要: 通过形态结构和早期发育过程的观察, 结合分子分析, 对采自青岛(模式标本产地)的缢基蜈蚣藻(Grateloupia constricata Li et Ding)进行了重新鉴定。结果表明: (1)藻体直立, 单生或丛生, 呈红褐色或紫红色, 质地黏滑, 软骨质, 高10—30 cm, 主枝扁平; 1—3回羽状分枝, 小枝对生、互生或偏生, 基部缢缩; 藻体由皮层及髓部构成, 皮层由7—10层细胞组成, 厚80—120 μm, 髓部由不规则排列的髓丝组成, 雌配子体的果胞枝生殖枝丛主枝和辅助细胞生殖枝丛主枝分别由6个和5个细胞构成, 为典型的Grateloupia(6cpb—5auxb)型; 四分孢子囊经十字分裂形成。上述特征均与亚洲蜈蚣藻(G. asiatica Kawaguchi et Wang)一致。(2)缢基蜈蚣藻孢子的早期发育类型为“间接盘状体”型, 其早期发育过程与亚洲蜈蚣藻一致。(3)基于rbcL基因序列构建的系统树显示, 8个缢基蜈蚣藻样本之间无碱基差异, 与青岛和大连的亚洲蜈蚣藻均无碱基差异, 形成独立的进化支, 与韩国和日本的亚洲蜈蚣藻碱基差异分别为2 bp(0.17%)和3 bp(0.25%), 均属于种内差异; 基于COⅠ基因序列构建的系统树显示, 8个缢基蜈蚣藻样本之间无碱基差异, 与产于韩国的亚洲蜈蚣藻无碱基差异, 形成独立的进化支; 通过形态、结构及基因序列分析, 确定缢基蜈蚣藻与亚洲蜈蚣藻为同一种, 根据优先法则, 将缢基蜈蚣藻作为亚洲蜈蚣藻的同物异名。

     

    Abstract: Through morphological and early development observation followed by molecular analysis, we re-examined Grateloupia constricata Li et Ding collected from Qingdao, Shandong Province. The results showed that: (1) The thalli were upright, brown-red or purple-red, single or clustered, up to 10—30 cm high fleshy and gelatinous in texture. The first branch was flat with pinnately branched 1—3 orders. The branches were reversed, alternate or partial and usually constricted or tapered at the base. Thallus were composed of cortex and medulla. The cortex had 7—10 cell layers and the medulla was consisted of many rhizoidal filaments, 80—120 microns thick, The medulla is consisted of an irregular arrangement of medullary filament. Carpogonial branch ampullae had six cells, auxiliary cell ampullae had five cells (6cpb-5auxb type). Gametophytes dioecious, mature tetrasporangia originated from inner cortex cells and splited into cross. The above characteristics were similar to those of G. asiatica Kawaguchi et Wang. (2) The early developmental type of G. constricata Li et Ding was ‘mediate discal type’, which is consistent with G. asiatica. (3) Based on the phylogenetic tree constructed by rbcL sequences, there was no sequence divergence between the eight samples of G. constricata and G. asiatica from Qingdao and Dalian, which formed a single monophyletic subclade within the large Grateloupia clade of Halymeniaceae. The rbcL sequences differences between G. constricata and G. asiatica from South Korea and Japan were 2 bp (0.17%) and 3 bp (0.25%), which were intraspecific difference. Based on the phylogenetic tree constructed by gene (COⅠ), there was no sequence divergence between the eight samples of G. constricata and G. asiatica from South Korea, which formed a single monophyletic subclade. Consideringmorphological observations and molecular analysis, G. constricata Li et Ding and G. asiatica Kawaguchi et Wang were proved to be the same species. Accroding to the priority rule, G. constricata Li et Ding was the synonym of G. asiatica.

     

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