The objective of this research was to study the tetrazolium solution concentration and staining period for the evaluation of the physiological quality of castor bean seeds (Ricinus communis L.) by the tetrazolium test, standardizing the nomenclature of the observed colors in seeds after staining. The treatments of tetrazolium solution concentration and staining period were: 0.075% and 0.1% for 120, 180 and 240 minutes, 0.2% for 60, 120 and 180 minutes, 0.5% for 60, 90 and 120 minutes and 1.0% for 30, 60 and 90 minutes. The results were compared to the germination test. The seed color after the tetrazolium test in each treatment was evaluated by comparing with the Munsell book of color, and the percentage of seeds observed in each color was established. A randomized complete block design was used and the means were compared by the Tukey test at the 0.05 level of probability. To evaluate physiological quality by the tetrazolium test, castor bean seeds should be placed in tetrazolium solution at the concentration 0.2% for 120 minutes, at 35ºC, for staining development, and in this treatment, the viable seeds after the staining in tetrazolium solution showed predominantly the colors pink and dark pink in their essential structures. Thus these colors can be considered as the characteristics colors for the tetrazolium test in castor bean seeds.
viability; methodology; color
