Características fisiológicas de plantas daninhas e culturas após fumigação do solo

This work aims to evaluate the physiological characteristics of weeds (Ageratum conyzoides L., Bidens pilosa L., Cenchrus echinatus L., Conyza bonariensis L., Echinochloa crus-galli L., Eleusine indica L., Ipomoea grandifolia L. and Lolium multiflorum L.) and crops (bean and maize) in soil fumigated and not fumigated. At 50 days after emergence, evaluations were made in the middle third of the first fully expanded leaves. For it was used an infrared gas analyzer. Were determined substomatal CO2 concentration, photosynthetic rate, and calculated the CO2 used from the reference values of CO2 and CO2 in the evaluation chamber, stomatal conductance to water vapor, the temperature gradient between leaf and air, transpiration rate, calculated yet the efficiency of water use. The physiological variables of beans and corn were negatively affected by sterilization of soil and related weeds, the ryegrass was influenced by sterilization.