Effects of nitrogen dioxide on Phaseolus vulgaris in urban environment

Abstract

The vehicles are responsible for significant emissions of nitrogen oxides (NOx). Among them, NO2 has a huge importance in the formation of the atmospherics’ reactions that cause the photochemical smog, and can become hazard to the health, agriculture and materials in general, when they are in high concentrations. The objective of present work was to investigate the effect produced by the environmental concentrations of NO2 in Phaseolus vulgaris L. cv. Iraí, through the possible relation between the activity of the Nitrate Reductase (NR) enzyme and the atmospherical concentrations of NO2. The plants were exposed in three sample places, located at increasing distances of a very intense urban traffic way. The concentration of NO2 in the air was determined by the Griess-Saltzman method. The nearest point to the avenue presented the highest concentration (40.3g m-3). In the 20, 50 and 70 days of exposition, the plants were analyzed by the activity of their NR enzyme, total biomass, leaf area, photosynthetic activity (A/Ci response) and chlorophyll a and total. The concentrations of atmospheric NO2 found did not present a significant effect over the analyzed parameters.