The objective of this study was to establish criteria for the tetrazolium test in embryos of macaw palm (Acrocomia aculeata). To develop the evaluation scheme, anatomical analyses were performed, and staining patterns were identified using a 0.5% 2,3,5-triphenyl tetrazolium chloride solution for four hours, and embryo was cultured in vitro. In one experiment, three prior seed-soaking times in water (for 12 and 24 hours, besides a control without seed pre-conditioning), associated with two color temperatures (35 and 40ºC) in two seed lots were evaluated. In another experiment, three concentrations of tetrazolium solution (0.5, 0.75 and 1%), associated with two staining times (two and four hours), were tested in three seed lots. In vitro embryo culture was used to compare the results. An evaluation scheme, with ten staining patterns associated with three classes of vigor, was defined, based on the anatomy of the embryo and on the in vitro seedling development. Pre-soaking is not necessary, and staining for four hours in a solution of tetrazolium salt, at 0.5% and 35ºC, should be used.
Acrocomia aculeata; 2,3,5-triphenyl tetrazolium chloride; in vitro embryo culture
