Study On The Development Of Carpospores And Discoid Crusts Of Grateloupia Turuturu (Halymeniaceae, Rhodophyta)

The red algal genera Grateloupia C. Agardh belongs to Halymeniaceae, Cryptonemiales, Rhodophyta. It is reported that there are a total of about 80 species throughout the world, including 32 species in China. Grateloupia turuturu is one of a economic algae in Grateloupia. G. turuturu is native to the Japan and Korea, now occurs at the Atlantic and Mediterranean Sea as well as southern Pacific Ocean. More and more yield of G. turuturu is increasingly required to meet the exploitation and utilization in the field of foodstuffs, natraceuticals and industrial anti-microfouling applications of secondary metabolites. However, production of G. turuturu from the wild resource couldn't satisfy the market need. Although there are many documents about the life cycle of G. turuturu, no reports involved in early developemt of carpospores has been carried out. Studies on early development of carpospores and discoid crusts of G. turuturu will not only help to understand the details of life cycle in G. turuturu, but also could provide support for germplasm conservation and seedling culture.In our study, early development of carpospores of G. turuturu was investigated under the culture conditions (27°C, 13μmol/m~2.s in irradiance, photoperiod 10:14 h L: D). Carpospores released from cystocarps after the fronds were treated in shade for 2 h and began to germination in 48 h. Three physiological stages were recognized as follows: division stage, discoid crust stage and juvenile seedling stage. It took 60 days for carpospores to develop into juvenile seedlings.At the beginning of the division stage, the carpospores developed germ tubes into which the carpospore protoplasm was evacuated. Septa were formed between the germ tubes and the carpospores, and then the protoplasm in the germ tubes began to divide into 4-8 cells in 3 days. At the discoid crust stage, successive irregular division of germ tubes gave rise to developing discoid crusts in 10 days. At the juvenile seedling stage, the discoid crusts arched slightly and upright thalli appeared gradually from basal parts. By the end of the second month, the discoid crusts grew with vigor and developed into juvenile seedlings.The effects of different irradiance and temperature on discoid crusts were also studied. The filaments obtained from discoid crusts which were stimulated by high irradiance (45μmol/m~2.s) could develop into discoid crusts again. Our results showed that higher irradiance (40μmol/m~2.s) could promote the development of filaments while low temperature (7℃) inhibited the development of filaments.