海南新纪录种台湾蜈蚣藻(红藻门)的形态学观察和rbcL与COI基因序列分析

通过形态结构观察结合rbcL和COI基因序列分析的方法,发现分布于海南省博鳌的台湾蜈蚣藻(Grateloupia taiwanensis S.M.Lin et H.Y.Liang)为海南新纪录种。结果表明:藻体直立,红色或紫红色,质地柔软黏滑,高6—18cm,宽2—3cm,叶片呈披针形,边缘长出的小育枝亦呈披针形,长5—25mm,宽1—5mm,固着器呈圆盘状;皮层由8—11层细胞构成,髓部非中空,髓丝纵走或相互交错;雌雄异体,精子囊由外皮层细胞形成,球形。果胞枝生殖枝丛主枝由6个细胞构成,辅助细胞生殖枝丛主枝由5个细胞构成(6cpb-5auxb型),均为典型的Grateloupia型。囊果散布于除固着器外的整个雌配子体的表面;四分孢子囊由四分孢子体的内皮层细胞产生,呈十字形分裂。rbcL基因序列分析结果显示4个采自海南的样本与产自台湾南部的台湾蜈蚣藻之间无碱基序列差异;COI基因序列分析结果显示4个样本间无碱基差异,在蜈蚣藻属这一大的进化支中聚集成独立的小分支,区别于其他种。

GRATELOUPIA TAIWANENSIS (RHODOPHYTA), A NEW RECORD OF HAINAN ISLAND BASED ON MORPHOLOGY, RBCL, AND COI GENE SEQUENCE ANALYSES

Four alga samples were collected in April 2014 in Boao, Hainan, South China and have been identified Grateloupia taiwanensis S. M. Lin et H. Y. Liang, a new record in the island. The species was previously reported in Taiwan, China, and Mexico only. This new record gains support from our morphological observations and rbcL and COI genes analyses. The results show the following. In morphology, thallus is upright, red to purple, soft and gelatinous in texture, lanceolate blades, 6-18cm high and 2-3cm wide, arising from a small discoid holdfast. Marginal proliferations are lanceolate in shape, 5-25mm long and 1-5mm wide. Cortex composed of 8-11 layers, the medulla is not hollow, the medullary filaments are narrow, and closely interwoven. Gametophytes are dioecious, the spermatangia of a male gametophyte are formed from the surface cells, spherical in shape. The species has 6-celled carpogonial branches and 5-celled auxiliary branches (6cpb-5auxb type), reflecting typical Grateloupia-type. The cystocarps scatter on the entire blade but the basal parts. Matured tetrasporangia originates from inner cortex cells and divided cruciately. In molecular biology, the rbcL sequence shows no pairwise divergence in the four samples from that of southern Taiwan, and so does in the COI sequence among the four samples, forming a single monophyletic subclade away from other species.