Ponce de Leon (IMAGE) Penn State Caption Lead researcher Maria Ponce de Leon, a former graduate student in plant science, carries a nitrous oxide emissions chamber into a corn field at Penn State's Russell E. Larson Agricultural Research Center to measure the amount of the potent greenhouse gas given off by the crop. Credit Heather Karsten, Penn State Usage Restrictions non commercial use only 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.