the effect of some environmental factors on biomass and agar content of gracilaria corticata (gracilariales, rhodophyta)

The effects of some environmental parameters on biomass and agar yield of gracilaria corticata were examined under laboratory conditions. the macroalga was collected from natural tidal pool with in bostaneh coast (the persian gulf) in may 2004. in the laboratory, biomass and agar yield were measured after 45 days examining effect of different temperatures (24, 27 and 32°c), photon irradiances (24, 66 and 94 photons m^-2s^-1), and concentrations of ammonium phosphate [unenriched seawater (0), 0.04 and 0.08 gl^-1] in culture. except for concentration of ammonium phosphate, other environmental variables showed no significant relationship (p>0.05) with biomass and agar content of g. corticata. the agar yield derived from the alga cultivated at 0.08 gl^-1 ammonium phosphate (22.40±1.81%) was significantly greater than the other treatments that makes g. corticata one of the commercial agarophytes (p<0.05).