One of the following is not related to Ernst Mayr.

Ernst Mayr did not carry out research in Plant Physiology. He carried out research in the fields of Ornithology, Taxonomy, Zoogeography, Evolution, Systematics and history and philosophy of biology. He was awarded triple crown of Biology (Balzan Prize, International prize of biology, and Crafoord prize). He was regarded as Alexander Agassiz Professor of Zoology and gave the currently accepted definition for biological species.