The development from kinetic coefficients of a predictive model for the growth of eichhornia crassipes in the field i. generating kinetic coefficients for the model in greenhouse culture
Musil, C.F.; Breen, C.M.
Bothalia 15(3-4): 689-704
The kinetics of N- and P-limited growth of Eichhorinia crassipes (Mart.) Solms were investigated in greenhouse culture with the object of developing a model for predicting population sizes, yields, growth rates and frequencies and amounts of harvest, under varying conditions of nutrient loading and climate, to control both nutrient inputs and excessive growth in eutrophied aquatic systems. The kinetic coefficients, maximum specific growth rate (Umax), half saturation coefficient (Ks) and yield coefficient (Yc) were measured under N and P limitation in replicated batch culture experiments. Umax values and Ks concentrations derived under N limitation ranged from 5.37 to 8.86% d-1 and from 400 to 1506 .mu.g N l-1 respectively. Those derived under P limitation ranged from 4.51 to 10.89% d-1 and from 41 to 162 .mu.g P l-1 respectively. Yc values (fresh mass basis) determined ranged from 1,660 to 1,981 (87 to 98 dry mass basis) for N and from 16,431 to 18,671 (867 to 980 dry mass basis) for P. The reciprocals of Yc values (dry mass basis), expressed as percentages, adequately estimated the minimum limiting concentrations of N and P (% dry mass) in the plant tissues. Kinetic coefficients determined are compared with those reported for algae. The experimental method used and results obtained are critically assessed.