SOME ASPECTS OF THE GROWTH OF GRACILARIA-TENUISITIPITATA IN POND CULTURE

The effect of temperature, salinity, nitrogen, culture density and dep th on the growth of Gracilaria tenuistipitata were investigated betwee n April 1985 and March 1986 in outdoor ponds in Guangxi Province, Sout h China. The mean annual growth rate was 2.4% per day. Under favourabl e temperatures of 20-30-degrees-C, daily growth rate may reach as high as 3.3%. Salinity had an obvious effect on growth and photosynthesis and growth peaked at 21 parts per thousand, with a broad plateau betwe en 7-27 parts per thousand. Growth experiments showed that a total nit rogen (NH4-N plus NO3-N) concentration of 4 muM was sufficient to enab le the plants to maintain a daily growth rate of 2.7%. The best growth of the plant was obtained at a culture density of 0.5-1 kg M-2 and a culture depth of 30 cm in the pond.