EFFECTS OF DIFFERENT P CONCENTRATIONS ON THE CHLOROPHYLL FLUORESCENCE AND GROWTH OF ISOCHRYSIS GALBANA 3011 AND 8701

The effects of different P concentrations(0,2.27,18.15,36.3,72.6 and 290.4μM) on the maximal photochemical efficiency of PSII(Fv/Fm),chlorophyll contents and cell densities of two marine microalgae,Isochrysis galbana 3011 and 8701 are reported.The algae were obtained from the Microalgae Culture Center(MACC),the ocean university of China.The cultures were grown at 23 1℃,the salinity was adjusted to 31 by using distilled water,and the light intensity was 5000lx.One-way analysis of variance showed that the P concentrations have significant effects on the photosynthesis and growth of the two microalgal strains with increasing culture age(P0.05).For Isochrysis galbana 3011 and 8701,the values of Fv/Fm,chlorophyll contents and cell densities,all increased with the increase of P concentrations and reached their highest values at 290.4μM.Multiple comparison tests showed that the optimal P concentrations for the photosynthesis and growth of Isochrysis galbana 3011 and 8701 are both 290.4μM.