A solar wind model with protons, electrons, O VII and O VI ions is studied. It is found that ionization and recombination processes lead to an approximately constant density ratio of the oxygen states (nO VI/nO VII≈const≪1) in the solar wind acceleration region. Although ionization and recombination have a significant effect on the flow speed of the O VI ions, these processes are not fast enough to bring the speed of O VI up to the flow speed of the O VII ions. ¿ American Geophysical Union 1990