Distinguished for his contributions to knowledge of the absorption of ions by plant cells, and for his work in the applied field of Plant Physiology. Robertson in a fine series of studies showed, inter alia, that the rate of passage of inorganic ions into plant cells is determined by the respiratory process, and is dependent upon the Cytochrome System for the energy necessary to effect it. His fundamental studies on the metabolism of Apples provided a fund of exact knowledge upon which modern methods of storage of this fruit are based. His work both in the fundamental and applied fields has been very widely recognised. He is the leader of a vigorous research team.