Composite B (IMAGE) University of Missouri-Columbia Caption The exponential increase in expression of HAESA in the abscission zone of Arabidopsis thaliana (shown here using a fluorescent protein) is driven by a molecular feedback loop. Credit University of Missouri Biological Sciences Division 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.