Tank culture of Gracilaria heteroclada (Zhang et Xia)

Abstract

Culture conditions in tanks were manipulated to improve the growth and agar quality of Gracilaria heteroclada Zhang et Xia. Specific growth rates during culture ranged from -0.51% to 1.40% and gel strength of agar from 439 to 2155 g cm^-2. G. heteroclada at a stocking density of 2kg ton^-1 and fertilized with ammonium chloride at 40 mg L^-1 grew best when water was changed once a month and ammonium chloride was replenished at 20 mg L^-1 after water change. When water was not changed, good growth was observed in plants supplied with 1 mg L^-1 diammonium phosphate on the 3rd wk of culture.