Abstract
The growth model of Pistia stratiotes L. (Pistia-model) was verified using two independent sets of published field data (07° 26' N, 03° 53' E Nigeria; 27° 30' N, 80° 30' W USA) to answer the following question: Is the Pistia-model, originally designed for P. stratiotes under natural conditions in Egypt, suitable to simulate the growth of P. stratiotes in tropical and subtropical regions? The Pistia-model simulates the growth dynamics and biomass production of well-established, monospecific stands of P. stratiotes based on fixed carbon gain and loss using first-order differential equations. General trends for shoots biomass, such as the slow initial growth rate followed by a high growth rate, the peak biomass, and the decline of biomass due to senescence, were successfully reproduced by the Pistia-model. Many characteristics typical for the roots biomass, such as the increase in the roots biomass during the early growing season because of the translocation of materials from shoots, and the reduction of roots biomass during the later period of the season, were also reproduced. The level of agreement between the simulated values and actual field data indicated that the Pistia-model can simulate the biomass of P. stratiotes over a wide range of latitudes.