Effect Of Temperature And Irradiance On The Early Development Of Chondrus Ocellatus Holm (Gigartinaceae, Rhodophyta)

Chondrus is an economically important red seaweed which widely used for food and many other purpose. Its early development is crucial for the seedling production and culture. Here in our study, C. ocellatus thalli were collected in Qingdao, China, from Nov. to Dec. 2006. Effects of temperature and irradiance on the early development of C. ocellatus were investigated under laboratory conditions. Tetraspores and carpospores of C. ocellatus were cultivated at different temperatures(10～25℃) and irradiances(10,60μEm^-2s^-1) in 12:12h (light: dark). It was showed that the optimal temperature (20℃) is both suitable to the early development of tetraspores and carpospores, and a maximum growth occurred at above 60μEm^-2s^-1 irradiance. The carpospores showed a tolerance to temperature from 10～25℃, while the tetraspores were at 10～20℃.Besides normal development of sporelings, filamentous frond was either observed in our survey. It was composed of one or two rows of cells, which appeared from the outmost brim of the basal disc. Generally, filamentous fronds exhibited in self-existence or co-existence forms with normal young seedlings on the same basal disc, and the single cell detached from filamentous fronds developed into a new filamentous frond. These unique differentiation characters will either be potential for artificial seedling and nursery.