Resumo:
Coffee is one of the main agricultural commodities in the world. Thus, research aimed at reducing the productive risks of the crop has been increasingly encouraged, among which the use of plant hormones stands out. In addition, the objective of this work was to analyze the effect of the application of indole-3-acetic acid on the growth, nutrition and gas exchange of young Coffea arabica L plants. The experiment was carried out in the field in the city of Alegre, Espírito Santo, Brazil. The experimental design used was randomized blocks, testing the effect of the application of five doses of indole-3-acetic acid in young Arabica coffee plants, in four replications. The application of indole-3-acetic acid stimulates the growth rate of the stem diameter at a concentration of 60 mg L-1, as well as gas exchange in coffee plants, however it did not favor the increase in the substomatic concentration of CO2 instantaneous and intrinsic efficiency in water use and instantaneous carboxylation efficiency. Although the application of EIA was not able to provide direct gains in coffee growth during the experimental period, a longer evaluation of the treatments would possibly provide promising results for the coffee crop. The multivariate analysis showed that higher doses of auxin have a high relationship with the macronutrients studied.
