Studies On Selective Dominance Strains Of Dunaliella And Haematococcus Pluvialis

1.Studies on Selective Dominance Strains of DunaliellaThe eight strains of Dunaliella that were obtained from the Microalgae Culture Center (MACC),Ocean University of China were cultured under 25℃,the salinity was 31, the light intensity was 100μmolEm^-2s^-1. The three excellent strains of microalgae(Dunaliella salinaC43, Dunaliella sp.C46, Dunaliella salinaC39) that had rapid growth, higher photochemical efficiency and richβ-carotene content were selected from eight strains.The effects of different temperature, different salinity, different nutrient concentrations, et al on the maximal photochemical efficiency of PSII (F_v/F_m) , potential activity of PSâ…¡(F_v/F_o), actual photochemical efficiency of PSâ…¡in the light (ΦPSâ…¡), electron transport rate (ETR), chlorophyll contents, cell densities andβ-carotene content of the 3 strains of marine microalgae, Dunaliella salinaC43,Dunaliella sp.C46,Dunaliella salinaC39 were reported. One-way analysis of variance showed that temperature, salinity, nitrogen sources, N concentrations and P concentrations had significant effects on the photosynthesis, growth andβ-carotene content of the three strains of microalgae. Multiple comparison tests showed that the optimal temperature for the photosynthesis and growth of C43, C46, C39 were 30℃, 20℃, 25℃; the optimal salinity were 90, 30, 30; the optimal nitrogen sources were NaNO3 or (NH2)2CO; the optimal N concentrations were 880μM, 440μM, 1760μM and the optimal P concentration were 72.60μM, 18.15μM, 72.60μM, respectively.Moreover, the optimal salinity for the cellular maximum content ofβ-carotene were 150,90,90; the optimal N concentration was 0μM and the optimal P concentration was 0μM.The two excellent mutant strains of Dunaliella salina C39 by ultraviolet radiation had been identified.The fluorescence parameters(F_v/F_m,F_v/F_o,ΦPSâ…¡,ETR) and relative growth rates of the two mutant strains were found to be significantly higher than Dunaliella salina C39 were. But the cellularβ-carotene content of the two mutant strains was lower than Dunaliella salina C39 was. 2.Studies on Selective Dominance Strains of Haematococcus pluvialisThe effects of different temperature, different illumination, different nutrient concentrations, et al on the maximal photochemical efficiency of PSII (F_v/F_m) , potential activity of PSâ…¡(F_v/F_o), actual photochemical efficiency of PSâ…¡in the light (ΦPSâ…¡), electron transport rate (ETR), chlorophyll contents, cell densities and astaxanthin content of Haematococcus pluvialis were reported. One-way analysis of variance showed that temperature, illumination, nitrogen sources, N concentrations and P concentrations had significant effects on the photosynthesis, growth and astaxanthin content of H.pluvialis. Multiple comparison tests showed that the optimal temperature for the photosynthesis and growth of H. pluvialis was 20℃; the optimal illumination was 50μmolEm^-2s^-1; the optimal nitrogen sources was NaNO₃ or (NH₂)₂CO; the optimal N concentration was 1760μM and the optimal P concentration was 18.16μM. Moreover, the optimal temperature for the cellular maximum content of astaxanthin was 5℃or 30℃; the optimal illumination was 300μmolEm^-2s^-1; the optimal N concentrations was 0μM and the optimal P concentration was 0μM. The three excellent mutant strains of H.pluvialis by ultraviolet radiation had been identified.The fluorescence parameters(F_v/F_m,F_v/F_o,ΦPSâ…¡,ETR) and relative growth rates of the three mutant strains were found to be significantly higher than H.pluvialis were. But the cellular astaxanthin content of the three mutant strains was lower than H.pluvialis was.