Radio Tracer Chamber (IMAGE) University of Missouri-Columbia Caption A radio tracer chamber at Brookhaven National Laboratory was needed to test if Setaria viridis actually used nitrogen produced by the bacteria. The scientists allowed only one leaf to contact the radioactive nitrogen, so they could truly tell if it was being used. Credit Courtesy of Fernanda Amaral Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.