Nitrogênio e níquel na cultura do milho: Efeitos nos pigmentos e trocas gasosas

Abstract

Nitrogen fertilization is essential for the good development of maize crop, however, for the best use of N, it is important the adequate nutrition with other elements, among which the micronutrient nickel (Ni) stands out. The aim of this study was to evaluate the effect of Ni foliar application on maize plants cultivated under different nitrogen fertilization conditions, with the hypothesis that the Ni applied favors the pigment contents and the photosynthetic metabolism of the plants. The experimental design was in randomized blocks, in a 3X2 factorial scheme, with three conditions of nitrogen fertilization: deficiency, recommended dose (130 kg ha-1 of N) and the excess (260 kg ha-1 of N), in the absence and presence of Ni (40 g ha-1 of Ni) applied via foliar application. In addition to determining the levels of chlorophyll and carotenoids, gas exchange measurements were performed using the parameters photosynthesis (A, µmol CO2 m-2 s-1), internal CO2 concentration (Ci, µmol CO2 mol-1), transpiration (E, mmol H2O m-2 s-1) and stomatal conductance (gs, mol H2O m-2 s-1). The application of Ni favors the chlorophyll contents in N deficiency and increases the stomatal conductance in plants grown under adequate N levels. The application of the micronutrient improves photosynthesis, stomatal conductance and internal CO2 concentration in maize crop plants.