Studies On Classification,Identification And Molecular Systematics Spp. Off The Coast Of Hainan Island

Sargassum is a kind of high-biomass and rich-resource economic algae, which is widely used in industry, agriculture, food, health care and other fields. Sargassum, belonging to Phaeophyta, Cyclospreae, Fucales, Sargassaceae, Sargassum, grows on the stone of the low-tide zone and the subtidal zone in tropical and temperate area. In China, Sargassum mainly distributes in Hainan, Guangdong, Guangxi and some other coastal rigions, especially its resource is abundant in Hainan province. But for a long time, there are a few researches about Hainan Sargassum, hence the understanding about the species diversity, the biological characteristics, the seeding propagation and deep processing was limited, this results in its backward state of large-scale cultivation and further processing. In order to accelerating the development and utilization progress of the Sargassum, carrying out studies of species and distribution of the Hainan Sargassum would play a very important role in understanding species diversity of Sargassum.This study collected the Sargassum off the coast of Hainan island in May and June2013, and got43Sargassum samples from Haitou town, Luhuitou, Changpo town and Tanmen town, according to morphological characteristic, there were20species including1newly discovered variation. The specific result was as follows:there were5species in the samples from Haitou, they were S. polycystum, S. odontocarpum, S. euryphyllum, S. siliquosum and S. mcclurei, respectively; there were2species in the samples from Luhuitou, they were S. sanyaense and S. dazhouense, respectively; there were8species in the samples from Changpo, they were S. sandei, S. duplicatum, S. yingehaiense, S. dotyi, S. symphyorhizoideum, S. crassifolium, S. ilicifolium and S. cristaefolium, respectively; there were7species in the samples from Tanmen, including1newly discovered variation, S. pseudolanceolatum var. tanmen, which had difference from the type species, it had oval vesicles, leaf edges packaged by thin laciness, needle on the top that the same length as the diameter of the vesicle, lobate suspensor, two rows of trichopores at both sides with sawteeth at the edge, which was longer than the vesicles, the remaining6species were S. integerrimum, S. oligocystum, S. yingehaiense, S. ilicifolium, S. cystophyllum var. parcespinosa, S. ilicifolium var. conduplicatum.By far, there are a few reports about Sargassum molecular systematics studies, basing on the reports in marine algae gene sequences, this study completed the cloning and sequencing of the coxI gene, rbcL gene and ITS gene, and got125new gene sequences, some gene sequences have been submitted to GenBank, enriched the gene sequences in the database. The primers used in this study were highly universal, the amplification efficiency of coxI gene was100%, the rbcL gene95%and the ITS gene95%. The analysis showed, the coxl gene length was700bp, G+C%was between36.0%-40.8%, its interspecific genetic distance was0.002～0.198; the rbcL gene length was617bp, G+C%was between29.8%-33.0%, its interspecific genetic distance was0.002～1.079; the ITS gene length was1689bp, G+C%was between57.8%-59.5%, its interspecific genetic distance was0.001～0.084. The analysis of the phylogenetic trees based on three gene showed that the species in Sargassum subgenus got together and had closer relationships with the species in Phyllocystae section, the result provided an evidence to support the taxonomic status redistricting of the species in Phyllocystae section.