The Influence Of Nutrient On M.Aeruginosa Growth In Simulative Equipment Of Experiment

The studies were established with M. aeruginosa, one of the most deleterious species of harmful algal blooms. P is one of the key elements that lead to eutrophication. The effects of different phosphorus concentration of water system on cell multiplication .DTP, P-in-cell of tissues(QP) and some biochemical constituents, colony character of M. aeruginosa, as well as the changes of environment factors(pH. DO, intensity of light) were studied in simulative equipment of experiment.The results about the effects of different P on the growth of M. aeruginosa in laboratory conditions were as flows:1 ,On conditions of abundant N, The maximum growth rates appeared when the concentration of P were 0.2mg/L.when TP>0.2mg/L, it did not influence the growth rate and biomass.2 ,The optimum N/P ratio of M. aeruginosa was 16:1; When N/P was higher than 16, the growth rate were much lower than it was lower 16, phosphate was the limiting factor of M. aeruginosa growth; The contents of carbohydrate was obviously affected by different N/P ratios, the content showed: 16: 1>5: 1>1: l>50: 1>100: 1.The results about the effects of different P on the growth of M. aeruginosa and environment factors in simulative equipment of experiment were as flows:1 , In the simulative equipment, the growth of algal was limited by p-limited(Tp<0.046 mg/L)firstly and then by light-limited(Tp>0.41 mg/L)with increasing of P concentration in the medium, and that above 1.71mg/L would inhibit growth; Ranging from 0.046mg/L to 0.41 mg/L , P-in-cell of tissues affected on the growth of M. aeruginosa. The most favorable concentration of P for its growth in simulative equipment was 0.41 mg/L.2 , The effects of P concentration on the growth rate of M. aeruginosa under simulative equipment can be described using the Monod equation and Droop equation. P half saturation constant for algae growth Km was 0.0156mg/L. the P subsistence quota of algae Q₀ was 0.23μg/ mg(dw), the max growth rate μ_max was 0.42(d^-1).3 , Diurnal changes in the simulative equipment of some environment factors and carbohydrate concentration were displayed with the growth of M. aeruginosa. The environment factors include pH. DO. The biomass of M. aeruginosa increased with the growth of alga andintensity of light decreased with the deep of water column, the growth grate of M. aeruginosa is negatively correlated with the deep of water column.4 n Under the condition of phosphate concentration addition, some biochemical constituents M. aeruginosa were affected, the contents of chlorophyll increase 50-70%(the best peak value); throw the linetype regression, when Tp=0.41 mg/L ,the speed synthesize of carbohydrate and protein is the best ..besides synthetic speed of carbohydrate is faster than accumulative speed of protein; Variations in protein-carbohydrate ratio (P/C) of biochemical composition of algal photosynthetic products could reflect its growth conditions in varied water environments.5 ?> Colony characters was strongly affected by different P concentrate .To sum up. phosphorus not only stimulate the growth of Microcystis directly bysupplying nutrient element, but also has complex interactions with other 'environmental factors' and play important roles in the growth processes.