Antioxidative metabolism: a tool to detect small differences in the vigor of soybean seeds

We aimed to differentiate the vigor of soybean seeds through antioxidant enzyme activity (superoxide dismutase-SOD, ascorbate peroxidase-APX, and catalase- CAT) and relate them to the viability and vigor standard tests to verify if these enzymes detect tenuous differences in seed vigor. The following tests were performed: germination, fi rst germination count, germination speed index, initial growth of seedlings, electrical conductivity, and respiratory and enzymatic activity. It was only possible to differentiate just two lots of soybean seeds by vigor and germination test, considering that viability had higher germination in lot 2 (91%), which did not differ from lot 3 (87.17%) nor from lot 1 (85.17%), while SOD and APX enzymes activity, in the roots, differed amongst the three lots. Thus, it was concluded that the viability and vigor standard tests relate to antioxidant enzyme activity, characterizing this method as an effi cient tool for detecting small differences in the vigor of soybean seeds.