The Early Development, Morphologic Observation And RbcL Sequences Analyses For Four Red Algae In Gigartinales

Studies on the four species from Gigartinales: Grateloupia asiatica Kawaguchi et Wang,Dumontia simplex Cotton, Chondracanthus sp., G. fastigiata Li et Ding. The study of earlydevelopment and life history were conducted on G. asiatica and D. simplex, as well as theinfluences of temperature and illumination ecological factors; morphological observation andrbcL sequences study were conducted on Chondracanthus sp. and G. fastigiata. The resultsshowed that:(1) G. asiatica Kawaguchi et Wang were “mediate discal type”(with filamentous fronds);The optimum temperature of spores development is15℃, and grow faster in the high lightcondition; G. asiatica showed a typical triphasic life history with isomorphic gametophytes,carposporophytes and tetrasporophytes, and a typical homotypic alternation of generations.(2) G. fastigiata Li et Ding:①thalli were mucilaginous in texture;②thalli at the baseare cylindrical;③the branch were one or twoirregular pinnate branched;④the cortex was85~160μm thick, consisting of four to five layers of cells;⑤carpogonial ampullae andauxiliary cell ampullae were of typical Grateloupia-type;⑥there is no intergenericdivergence among of the four specimens, the rbcL sequences showed no pairwise divergenceand the species formed a small single monophyletic subclade within the genus Grateloupiaclade, so it indicated that G. fastigiata is a single specie within Grateloupia.(3) D. simplex: the first division of D. simplex spores is transverse division, and thesecond is vertical split on the basis of transverse division, gradually form a multicellularstructures, irregularly arranged. One side of spores form protuberance, the protuberanceelongate and form discoid crust, then form upright gemmule (no filamentous fronds), and thegemmule continued to grow for a seedling; the optimum temperature of spores developmentis15℃, and the spores grow faster under low light condition. Whereas the spores dead underhigh light condition. The spores were “immediate discal type”; a typical triphasic life historywith isomorphic gametophytes, carposporophytes and tetrasporophytes, and a typicalhomotypic alternation of generations.(4) Chondracanthus sp.:①thallus are upright, purple, cartilaginous in texture;②thallus are solitary or caespitose;③5~10cm high,6~10cm wide;④thalli at the base arecylindrical;⑤thalluswere consisted of the cortex and medulla;⑥the four specimensformed a small single monophyletic subclade in the phylogenetic tree; there is1bp（0.09%） intergeneric divergence between the four specimens and Chondracanthus sp. Morbihan（JQ405738）from Morbihan; we concluded that the red algae of our research is the samespecie;⑦may be sister group to C. chamissoi distribute in Chile that evolve from the sameancestor;⑧The pairwise distances betweenC. intermedius and C. tenellus are59bp（5.2%）and64bp（5.7%）respectively，so Chondracanthus sp. is a new record specie.