Adjustment of the methodology of the tetrazolium test for estimating viability of Eugenia uniflora L . seeds during storage 1

The study aimed to adjust the methodology of the tetrazolium test to estimate seed viability of Eugenia uniflora L. (Surinam Cherry). Seeds were collected in September 2012 and divided into four lots: freshly harvested (Lot I); stored in plastic bags in a refrigerator at 10 °C for: 15 days (Lot II); 30 days (Lot III); and 45 days (Lot IV). The freshly harvested seeds were preconditioned with direct immersion in water and wet paper towel, followed or not by longitudinal cutting. The seeds were immersed in a 0.1% tetrazolium solution for 4 hours at 30 °C. Appropriate soaking and preparation methods were applied to the seeds lots using three tetrazolium concentrations: 0.1; 0.5; and 1.0%; and four preconditioning periods (2, 4, 6 and 8 hours) at 30 °C. The viability results obtained by the tetrazolium test were compared with those of the germination test. Direct immersion of seeds in water for 24 hours at 25 °C, followed by a longitudinal cut was efficient for preconditioning the seeds. Seed staining with tetrazolium solution at a concentration of 0.5% for 2 hours at 30 °C can be used to estimate the viability of freshly harvested and stored Surinam Cherry seeds.