Cell Elongation in Response to Ethylene (IMAGE) University of Maryland Caption Cell elongation in response to ethylene is seen in these microscopic images of Spirogyra pratensis filaments before (top) and after (bottom) exposure to ethylene. Credit Bram Van de Poel 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.