The experiment was carried out on the Plant Physiology Laboratory and in the
greenhouse of the Department of Biological Sciences- Experimental Botany Section at ESALQUSP
(Escola Superior de Agricultura Luis de Queiroz - University of São Paulo), from February
to June, 2000.Soybean seeds (Glycine max (L.) Merrill cv. IAC-8-2) were used, and the biostimulant
Stimulate (0.009% of kinetin, 0.005% of gibberellic acid, and 0.005% of indolbutyric acid) at the
following concentrations 1.0; 2.0; 3.0; 4.0 e 5.0ml/0.5kg of seeds, and 3.0ml of distillate water/
0.5kg of seeds as control (concentration zero of Stimulate).The objectives were to evaluate the
effects of the Stimulate on seed germination, seedling vigor, root growth and crop yield, as well as
to establish the product concentration applied on seeds. Germination and vigor tests were realized
with seeds and seedlings; germination percentage, percentage of normal and abnormal seedlings,
length and dry mass, seedling emergency, were observed. Rizotrons were used for the evaluate of
the roots system growth and the parameters related to the crop yield were obtained under greenhouse
conditions. The experiment design adopted was completely randomized with six treatments
(concentrations) and four replications. The results were analyzed using regression to the variables
that presented at least one difference between the evaluated concentrations. The conclusion achieved
at this study was that the 3.5ml Stimulate concentration proportionate the maximum quantity of
normal seedlings. An increase of 55.3% of seedlings dry mass was achieved with 4.1ml of
biostimulant concentration. The maximum vertical radicular growth were achieved at the 1.3ml
concentration, and 1.0ml of Stimulate/0.5kg of seeds caused a significant increase in grains and
grains dry mass, crop yield, up to the 5.0ml concentration, compared to the Stimulate zero
concentration.