Plant Cell Growth (image) Iowa State University Caption This illustration shows the parts of the expansin protein (magenta) that bind to the surface of specific regions of plant cell walls. Credit Illustration courtesy of Mei Hong/Iowa State University. Usage Restrictions None 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.