wheat roots (IMAGE) Penn State Caption Twelve wheat genotypes and six corn genotypes were grown in a greenhouse at the University Park campus. Large growth containers, or "mesocosms," were set up with a compacted soil layer to determine which roots penetrated the hard substrate. Credit Hannah Schneider, 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.