Teste de tetrazólio em sementes de pinhão-manso.

In recent years, demand and marketing of jatropha seeds increased, demanding the establishment of state and federal standards and developing appropriate methodologies for evaluating the quality of seeds. The tetrazolium test has become an important alternative for it's efciency and speed in determining the viability and vigor of the seeds, allowing to obtain results in less than 24 hours. Aiming to standardize a methodology for conducting the tetrazolium test in seeds of Jatropha curcas in evaluating the physiological quality. The initial evaluation of Jatropha curcas seeds was performed through standard germination, rst count germination, emergence and emergence speed index. Two experiments were conducted: the rst was conducted in a completely randomized design in a factorial scheme 4 x 4, where were tested four methods of preparation of the seed (seed-coats intact, whole seed, pre-soaked coated seed, coated seed distal cut on the region opposite to the caruncle, and whole seed, pre-soaking without the seed coat) and four concentrations of the tetrazolium (0,25%, 0,5%, 0,75% and 1,0%). For the evaluation of viability, seeds were sectioned longitudinally in the opening of the cotyledons. The most promising results in the rst trial were used as samples of the second test, which was also conducted in a completely randomized design in a factorial 3 x 3 (three times of immersion in tetrazolium solution 2, 4 and 6 hours and three concentrations – 0,25%, 0,5% and 0,75%), being that for the evaluation of the seeds were longitudinally sectioned transverse to the opening of the cotyledons. The second test was conducted at 2 temperatures (30oC and 40°C), being independent trials. Based on these results, it can be concluded that the tetrazolium test in jatropha seeds should be carried out at 0,5% concentration, within 6 hours of immersion at 40oC. The seeds should be pre-soaked with the seed coat, followed by it's removal for immersion in tetrazolium solution, using the longitudinal cut in the transverse direction of the opening of the cotyledons to evaluate the viability.