The color differences observed in the seeds after coloration in tetrazolium solution are the main features that should be considered when interpreting the test results. The color intensity of the seeds in the tetrazolium test varies among species. For example, the pink color seen in viable seeds of Leucaena (Leucaena leucocephala (Lam.) de Wit) is lighter (Costa and Santos, 2010) than that seen in seeds of Brachiaria brizantha (Hochst. ex A. Rich) Stapf (Dias and Alves, 2008).