Professor Gunning has made distinguished contributions to the elucidation of relationships between plant structure and function. His researches on membranes, organelles, microtubules and cell walls are key contributions in the fields of cell biology and morphogenesis. With Professor J. S. Pate, he discovered transfer cells and demonstrated their function. His papers and book on intercellular communication, have yielded new understanding of nutrient transport within plants. His use of electron microscopy has itself been imaginative and innovative. His book on plant cells has provided an ordered basis for future studies. His work on how organelles, cells and whole plants are organised to perform their vital functions is an outstanding contribution to biology.