Abstract: To evaluate the effects of amino acids on the growth and chlorophyll fluorescence parameters of blue green alga Microcystisaeruginosa, cell density, chlorophyll content and related chlorophyll fluorescence parameters including maximum light energy conversion efficiency(Fv/Fm) and electron transfer rate (ETR) were determined in the blue green alga cultured in the medium containing six kinds of amino acids—aspartic acid, serine, arginine, glutamic acid, alanine and glycine as sole nitrogen sources at a concentration of 12, 25, 50, 75, and 100 μmol/L under conditions of (30±1)℃, light intensity of 2 000 lx, and photoperiod of 12 L∶12 D. The results showed that there were significantly less alga cells, lower chlorophyll content and related chlorophyll fluorescence parameters in the nitrogen-free control group than those in the amino acid groups (P<0.05), with the increase in amino acid concentration, all the six amino acids leading to promote the growth and chlorophyll fluorescence parameters of the blue green alga, with the maximal value at the amino acid concentration of 100 μmol/L. With the elapse of culture time, the number of alga cells, chlorophyll content and related chlorophyll fluorescence parameters were increased in other amino acid groups at first and then decreased as a whole, except for the obvious fluctuation of glutamic acid, basically consistent with the rules of lag period, logarithmic growth period and stable period. The different concentrations and kinds of amino acids were shown to be favorable for growth and chlorophyll fluorescence parameters, with descending order of the effect degree of amino acids as: aspartic acid>serine>arginine>glutamic acid>alanine> glycine. The findings provide some data reference for revealing the effect mechanism of amino acids on the blue green alga in natural waters.
2021, Vol. 36 
