Gregory, Frederick Gugenheim

(b. London, England, 22 December 1893; d. London, 27 November 1961)

plant physiology.

Gregory’s unusual abilities in mathematics, physics, and chemistry enabled him to foresee the major role that biochemistry and physics would play in physiology and development. This ability, along with his voracious scientific curiosity, extended his work over an enormous range of topics; and it is difficult to select his chief contributions to botanical science. His development of new methods of growth analysis and introduction of the term “net assimilation rate” to denote average photosynthetic efficiency of leaves (i.e., the dry weight of the plant divided by the average area of leaf surface and number of hours of light) were the basis of his early reputation.

With O. N. Purvis he proved that the effect of controlled low (1 °C.) temperatures which will convert a “winter” rye to a “spring” rye—the effect known as vernalization—is exerted upon the embryo itself. They showed that excised embryos can be vernalized in the presence of sugar and a minimal oxygen concentration and that the effect is specifically due to temperature. This work and other work with F. J. Richards on mineral nutrition, aimed at determining the physiological causes underlying crop growth, also attracted much attention because of their value to agriculture.

The outcome of Gregory’s 1928 visit to the Gazira Research Station in the Anglo-Egyptian Sudan was an increased knowledge of the factors affecting cotton production and provided the basis for strengthening the economy of the Sudan. Although he never returned to Gazira, he advised from London and served on both the Scientific Advisory Committee of the Empire Cotton Growing Corporation and the London Advisory Committee in Agricultural Work in the Sudan. His invention of the resistance parameter and the diffusion parameter enabled sophisticated study of stomatal physiology and the factors controlling transpiration.

All of Gregory’s scientific career was spent in association with the Imperial College of Science and Technology, a constituent college of the University of London. The vast number of students and visitors who were influenced by their contact with him represents one of his lasting achievements.

In 1915 Gregory graduated from the Royal College of Science with first-class honors in botany. Having been rejected by the army on physical grounds, he joined the recently founded Research Institute of Plant Physiology at Imperial College under Vernon Blackman. Gregory began his work at Cheshunt Experimental Station, moved to Rothamsted, and finally returned to Imperial College. In 1932 he was appointed assistant director of the Research Institute of Plant Physiology and later succeeded Blackman as professor of plant physiology and director. Elected a member of the Royal Society in 1940, he was awarded its coveted Royal Medal in 1957. In 1956 he was elected a foreign associate of the National Academy of Sciences of the United States.

BIBLIOGRAPHY

I. Original Works. Gregory’s works include “Physiological Conditions in Cucumber Houses,” in Report. Experimental and Research Station, Nursery and Market Garden Industries Development Society, 3 (1917). 19–28: “Studies in the Energy Relation of Plants. I. The Increase in Area of Leaves and Leaf Surface of Cucumis satiuum,” in Annals of Botany, 35 (1921), 91–123; “The Effect of Climatic Conditions on the Growth of Barley,” ibid., 40 (1926), 1–26; “Studies in Energy Relations of Plants. II. The Effect of Temperature on Increase in Area of Leaf Surface and in Dry Weight of Cucumis sativum. Part 1. The Effect of Temperature on the Increase in Area of Leaf Surface,” ibid., 42 (1928), 469–507; and “Mineral Nutrition of Plants:’ in Annual Review of Biochemistry,6 (1937), 557–578.

See also “Physiological Studies in Plant Nutrition. VI. The Relation of Respiration Rate to the Carbohydrate and Nitrogen Metabolism of the Barley Leaf as Determined by Nitrogen and Potassium Deficiency,” in Annals of Botany, n.s. 1 (1937), 521–561, written with P. K. Sen; “Studies in Vernalization of Cereals. II. The Vernalization of Excised Mature Embryos and of Developing Ears,” ibid., n.s. 2 (1938), 237–251, written with O. N. Purvis; and “The Interrelation Between CO₂ Metabolism and Photoperiodism in Kalanchoë,” in Plant Physiology, 29 (1954), 220–229.

II. Secondary Literature. On Gregory or his work see Helen K. Porter, “Prof”. F. Go Gregory, F.R.S., in Nature, 193 (1962), 118; Helen K. Porter and F. J. Richards. “Frederick Gugenheim Gregory 1893–1961,” in. Biographical Memoirs of Fellows of the Royal Society, 9 (1963), 131–153, with complete bibliography; F. C. Steward, “F. G. Gregory 1893–1961:’ in Plant Physiology, 37 (1962), 450; and The Times (London), an obituary (30 Nov. 1961), 15a; and a funeral notice (4 Dec. 1961), 12c.

A. D. Krikorian