Isolation Of Algae From Chaohu Blooming Lake And Inhibitory Effects Of Lotus On Cyanobacteria

The main algae that cause the Chaohu Lake bloom are separated,and the biological control method is used.It using the characteristics of lotus can produce allelopathy during the growth process,to explore whether the lotus can inhibit algae cells.Therefore,this study is mainly divided into three parts.The first part separates and identifies the flora that causes the Chaohu Lake bloom;The second part studies the growth characteristics of different algae species isolated;The third part is to explore the influence of "Space Lotus" on the isolated Microcystis aeruginosa.The conclusions reached are:1.Two pure algae were isolated from the Chaohu Lake.It was identified by morphology and molecular level as: Chlorella sorokiniana of Chlorella chlorella,and Microcystis aeruginosa of Microcystis aeruginosa.2.The basic growth characteristics of the two isolated pure algae were studied: the optimum medium for Chlorella sorokiniana is Knop medium with a pH of 8(Knop medium).The optimum growth conditions is under 25°C and light 16 h everyday.When treated with antibiotics,10mg/mL rifampicin slightly inhibited it,and the inhibition rate reaches 17.26%,Gentamicin,ampicillin,kanamycin,tetracycline promote rate of 18.18-21.48%.Microcystis aeruginosa is toxic and secretes microcystins.The optimum medium for Microcystis aeruginosa is BG-11 medium with a pH of 7.0.The most suitable condition is under 30°C and light for 16 h everyday,In addition to the slight inhibition rate of tetracycline on Microcystis aeruginosa,gentamicin,ampicillin,kanamycin and rifamycin severely inhibited the growth of Microcystis aeruginosa,reaching an inhibition rate of 95.08-99.86%.So we can know Microcystis aeruginosa is sensitive to gentamicin,ampicillin,kanamycin,and rifampin.3.The effect of lotus on the growth of Microcystis aeruginosa:(1)Different tissue parts of lotus and lotus planting water had significant algae-inhibiting effects,The difference in inhibition between different tissues was not significant,and the inhibition effect of planting water on the fourth day was slightly lower than that of different tissues.(2)The inhibitory effect still works when the lotus planting water is dealed by suction filtration,corresponding the chlorophyll content keeps lower.While the planting water of lotus was autoclaved,the function was gone.So the chlorophyll content of Microcystis aeruginosa grows normally.(3)Put the algae blooming water from the Chaohu Lake into the lotus planting area.It was found a significant inhibitory effect on the concentration of different initial algae.Therefore,it can be known that the allelopathic substance of the lotus is continuously released into the water along the growth process,and the high temperature causes the allelopathic substance to lose the algae-inhibiting activity,which may occur by affecting its normal photosynthesis.