Effects Of Low Temperature Induction On The Light Demand Of Microcystis Aeruginosa In Dianchi Lake

Over the past 20 years,the frequent outbreaks of Microcystis aeruginosa in Dianchi Lake has become a hot topic of social concern.for causing great harm to the water environment and the drinking water safety of the local people.To achieve control of cyanobacteria outbreaks,there must be a scientific prediction of it.For a long time,the study of Microcystis aeruginosa mainly focused on the growth of temperature,light,nutrients,but there is no real breakthrough in the prediction of cyanobacteria outbreak.In recent years,Guo Weihua research team revealed that the Microcystis aeruginosa in Dianchi Lake have vernalizing effects,which mean that low temperature has the effect of promoting algal growth,and found the reasons why the algae had a demand for low temperature.Which is because the low temperature could relieve the dormancy effect of dormancy and the inhibitory effect of high temperature on the algae.The discovery of vernalization of Microcystis aeruginosa in Dianchi Lake provides basic theoretical support for algae prediction.In order to study on the prediction techniques of Microcystis aeruginosa in Dianchi Lake must be understand the relationship between the growth of Microcystis aeruginosa in Dianchi Lake and the induced low temperature and light intensity,and to provide the basic theoretical support for algae prediction,we conducted the experiments of the growth of algae in different light conditions after low temperature induction.And we analyzed the relationship between the transition temperature and the low-temperature induction and the light requirement of algae,the changes of light requirement of algae during the vernalization process at 9?,the rescission effect of low temperature after different high temperature,the lowest light intensity and suppresses light intensity of algae growth and so on.The results and conclusions were as follows:?In the transition temperature(which is the temperature of algae through no light between two low temperature induction)experiment at 19 ?,two algae growth rates of strong and weak light intensity change in the same in four rounds experiments.In the transition temperature experiment at 31 ?,the relationship between the two growth rates of the strong and low light intensity is that the results of the 1,3-cycle experiment are the same and the results of the 2,4-round experiment are the same,but the results between the 1,3-cycle experiment and the 2,4-round experiment is opposite.It is shown that the transition temperature makes light intensity demand different at different induced low temperature,and the change of the relationship between the two growth rates is objective.The relationship between them is achieved by the transition temperature of 31 ?.31 ? transition temperature is the condition that the relationship between the two growth rates is opposite,and the transition temperature of 19 ? is the condition that the relationship between the two growth rates is same.The transition temperature of 31 ? can stable growth rate of the relationship between the two growth rates,19 ? is no such effect.?The outbreak time of Microcystis aeruginosa in Dianchi Lake is related to the light demand of algae.The prediction of algae should be taken into account when algae is predicted.?The maximum increase rate of vernalization of algae is about 42.3%.The time of optimum induction low temperature to reach the maximum growth rate of algae is the shortest.The time of non-optimum induction low temperature reaches the maximum growth rate of algae need to extend.The demand for strong light from non-optimum induced temperature can be appropriately shortened to the maximum growth rate of algae.It is shown that as long as it can make algae demand for strong light,other induced low temperature is also easy to cause algae outbreak.?With the temperature rise,high temperature on the inhibition of algae and dormancy effect also increased when the growth of different high temperature and dormant high temperature act on the algae?It is shown that the degree of inhibition of algae is related to the strength of high temperature,the degree of dormancy of algae is related to the intensity of dormancy,and different induced low temperatures and different light intensities had no significant effect on the tendency of high temperature inhibition.?The lowest light intensity for algae growth was 420 lx and the photoinhibition light intensity of algae was 12650 lx.