[en] In Plasma Polarization Spectroscopy (PPS), we observe the polarized spectral lines emitted from a plasma. For berylliumlike oxygen lines from a tokamak plasma the polarization feature is interpreted as due to the anisotropic velocity distribution of electrons which excite the ions. In this interpretation in terms of the population-alignment collisional-radiative (PACR) model various collision processes are involved concerning the population and the alignment; e.g., transfer of the alignment) and the coherence by collisional excitation and production of an alignment from a population by elastic collisions. These latter processes are little known so far. (author)