Effects Of Nutrient Limitation On The Chlorophyll Fluorescence Of 6 Microalgal Strians

1 Effects of different nutrient concentrations on the chlorophyll fluorescence and growth of 6 microalgal strainsThe effects of different N concentrations (0μM,55μM,440μM,880μM,1760μM and 7040μM) and different P concentrations (0μM,2.27μM,18.15μM,36.3μM,72.6μM and 290.4μM) on the maximal photochemical efficiency of PSII (Fv/Fm) , chlorophyll contents and cell densities of the 4 strains of marine microalgae, Dunaliella salina,Chaetoceros gracilis, Isochrysis galbana 3011 and 8701 and different silicon concentrations (0μM,12μM,24μM,48μM,96μM and 384μM) on Phaeodactylum tricornutum, Chaetoceros gracilis and Nitzschia closterium f. minutissima are reported. The algae were obtained from the Microalgae Culture Center (MACC), Ocean university of China. The culture was controlled under 23±1℃, the salinity was adjusted to 31 by using distilled water, and the light intensity was 100μmol/m2·s. One-way analysis of variance showed that nutrient concentrations have significant effects on the photosynthesis and growth of the 6 strains of microalgae. Multiple comparison tests showed that the optimal N concentrations for the photosynthesis and growth of D. salina, C. gracilis, I. galbana 3011 and I. galbana 8701 are 1760μM, 1760μM, 7040μM and 440μM, respectively; the optimal P concentration are 290.4μM, 18.15μM, 290.4μM and 290.4μM, respectively; and the optimal Si concentration on P. tricornutum, C. gracilis and N. closterium f. minutissima are 384μM, 96μM and 384μM, respectively.2 Nutrient induced fluorescence transients (NIFT) after the addition of limited nutrient4 strains of marine microalgae, D. salina, C. gracilis, I. galbana 3011 and I. galbana 8701 without N or P and P. tricornutum, C. gracilis and N. closterium f.