Phytochrome Mutants (IMAGE) Washington University in St. Louis Caption Phytochrome mutants grow very differently from wild type plant (upper left) under the same conditions. Work with these mutants reveals that phytochrome is both a light and temperature sensor. Credit Vierstra Lab. Usage Restrictions Please credit. 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.