Tetrazolium test for Pinus taeda: preparation, staining, and seed viability classes

Abstract: The objective of this work was to evaluate preparation and staining methods used in the tetrazolium test for Pinus taeda seeds, with the definition of viability classes. The procedures carried out were those described in the rules for seed testing in Brazil and Association of Official Seed Analysts, as well as an alternative method for the tetrazolium test. For each procedure, different combinations of types of seed cuts, concentrations of tetrazolium salt, and exposure periods were used. The test conducted with the alternative procedure (longitudinal cut adjacent to the embryo and staining of only the half with the embryo) is the most practical. The obtained results allowed classifying seeds into two different viability classes (viable and nonviable), and 0.2% tetrazolium salt for 4 hours is the most effective combination.