The Effect Of Environmental Factors On The Gowth And Photosynthesis Of Microcystis Aeruginosa

Photosynthesis is the most basic and important physiological and ecological characteristics of algae.Studying photoperiod, temperature and pH value on the growth of Microcystis aeruginosa and the chlorophyll fluorescence is conducive to the growth of red tide algae bloom dynamics, and for prediction and prevention of the occurrence of red tide bloom to provide a theoretical basis, and has guiding significance for the use of algae in wastewater treatment.The paper researched the influence of 3 kinds of major environmental factors (light cycles, temperature and pH) on the growth and photosynthesis of Microcystis aeruginosa by the technique of chlorophyⅡfluoresence anaysis. In order to find out the response of Microcystis aeruginosa to different environmental factors, the 13 different light cycles,5 different temperature and 5 different pH values were set in this experiment. The main chlorophyⅡfluorescence parameters were determined in the present study including the maximal photochemical efficiency of PSⅡ(Y), the effective quantum yield of PSⅡ(Y'), the actual photochemical efficiency of PSⅡin the light(ΦPSⅡ), the relative electron transport rate(ETR), photochemical quenching(qP)and non-photochemicalquenching (qN,NPQ).1,The chlorophyll fluorescence parameter Y',qP, qN, NPQ,ΦPSⅡ, ETR can accurately reflect the photosynthesis of Microcystis aeruginosa. The chlorophyll fluorescence technology which may survey beautifully the physiological influence of the plant and algae's which environment threatened on, is a good probe for the algae photosynthesis-study.2,The growth and photosynthesis of Microcystis aeruginosa were infected by light cycles effect. When the light cycles were 0L/24D and 24L/0D, the growth and photosynthesis of Microcystis aeruginosa were inhibited obviously; The growth and photosynthesis of Microcystis aeruginosa were normal proceeding when the light cycle was from 8L/16D to 16L/8D. This showed that the appropriate light cycles's range of growth and photosynthesis of Microcystis aeruginosa was wide. Statistical analysis showed that there was little difference(P>0.05) in the growth status of Microcystis aeruginosa when the light cycles were 8L/16D-12L/12D, Chlorophyll fluorescence parameters and photoperiod have a significant correlation.The optimal light cycle for growth and photosynthesis of Microcystis aeruginosa was 12L/12D.3,The effect of temperature on Microcystis aeruginosa was very significant in the range of 10℃-35℃. the growth and photosynthesis of Microcystis aeruginosa were kept down when the temperature was low. the tolerable temperature range of Microcystis aeruginosa was 20℃-35℃. The optimal temperature for growth and photosynthesis of Microcystis aeruginosa was 25℃. In the different temperature condition, the ChlorophyⅡfluorescence parameters Y,Y',ΦPSⅡ,ETR,NPQ,qP and qN had significant difference, and had correlation with temperature.4,The growth of Microcystis aeruginosa was kept down in the acid environment. However, the growth and photosynthesis of Microcystis aeruginosa were active both in neutral and alkaline environment. In the different pH value condition, the growth and ChlorophyⅡfluorescence parameters had significant difference (P<0.05), which showed that the effect of pH value on the growth and photosynthesis of Microcystis aeruginosa was significant.