Storage, Cutting and Culture Conditions of Filamentous Roots of Hiziki Sargassum fusiforme

Abstract

To develop an artificial seedling production method of Hiziki, Sargassum fusiforme, the effect of storage, cutting and culture conditions on the formation of erect stem from filamentous roots separated from holdfasts were examined. After the Hiziki harvest in end of April 2007, holdfasts remaining on cultivation ropes were collected, loosened to separate the filamentous roots and washed with the culture medium. Optimum storage irradiance of the filamentous roots, temperature and irradiance for erect stem formation and growth, and the width of cut filamentous roots were examined. Optimum temperature and irradiance to store filamentous roots were 12degC and 25micromol/square m/s at 12L:12D cycle. A temperature of 23degC and irradiances ranging 120-230micromol/square m/s at 12L:12D cycle were more suitable for erect stem formation and growth. Forty culture days after cutting, 85% of the filamentous roots formed erect stems and the mean total length of young thalli reached about 5mm. Filamentous roots cut finely to less than 2.5 mm width resulted in 3 times more erect stems than those cut to larger than 5mm. Above results suggest the possibility of artificial seedling production from cut filamentous roots.