Methodology adequation of tetrazolium test for Hymenachne amplexicaulis seeds.
The Hymenachne amplexicaulis is a grass, considered a weed in the flooded Rice. Its seeds, measure about three millimeters in length and its panicles can produce a large number of viable seeds. This study aimed to establish the appropriate methodology for evaluate the viability of seeds of H. amplexicaulis using tetrazolium test. The tests, with completely randomized design, were conducted in the Herbology Didactic of Laboratory and Seed Laboratory for Didactic and Research, Universidade Federal de Santa Maria in 2010. For the germination test, treatments seed protected by their glumes and without these (naked) were exposed to potassium nitrate at a concentration of 0.2% or distilled water (control). For the tetrazolium test, naked seeds were immersed directly in water for 6, 12 and 24 hours periods at 23°C±1°C. Subsequently, the seeds were incubated in a solution of 2,3,5-triphenyl tetrazolium chloride at a concentration of 0.5%, at this temperature and followed-up the evolution of coloration. The seeds were classified as viable or non-viable, according with parameter predetermined, followed by data analysis. The imbibition of seeds without glumes, for six hours, with subsequent immersion in a solution of tetrazolium 0.5% for four hours was effective in determining the viability of seeds.