Obituary: Professor Edmund Yemm

Edmund William Yemm, plant physiologist, biochemist and ecologist: born Countesthorpe, Leicester 16 July 1909: Melville Wills Professor of Botany, Bristol University 1955-74, Pro-Vice- Chancellor 1970-73; married 1935 Marie Solari (one son, three daughters); died Stanton Drew, Avon 22 November 1993.

EDMUND YEMM was head of the Department of Botany at Bristol University from 1955 to 1974, a Pro-Vice-Chancellor of the university and an outstanding plant physiologist and ecologist.

At Wiggeston School, in Leicester, Ted Yemm was not only a very able pupil but also a considerable athlete, being captain of rugby and cricket. An Open Scholarship took him to Queen's College, Oxford, where he was awarded First Class honours in Natural Sciences (Botany) and was a football Blue from 1929 to 1931. His first research, funded by a Christopher Welch Scholarship at Oxford, was guided by the renowned plant physiologist W. O. James. Methods for the assay of plant carbohydrates were developed, and Yemm's skill at the bench, his ability in experimentation and his rigorous interpretation became very clear.

This research, which was extended to many aspects of the respiration of barley, and later of nitrogen metabolism, led to important publications in the Proceedings of the Royal Society, the New Phylologist, the Biochemical Journal and other periodicals. Much light was thrown on the complex interrelationships between carbohydrate and nitrogen metabolism and the role of the amide glutamine. Such studies led to a Rockefeller Foundation award and visits to Cornell and Western Reserve Universities.

In 1938 Yemm was appointed Lecturer in Botany at Bristol University where, apart from national service, in which he was involved in radar and the development of penicillin, he spent the rest of his working life. He was made a Reader in 1950, Professor of Botany in 1955, Dean of the Faculty of Science 1962-65 and later a Pro-Vice-

Chancellor. As a teacher, he was first class, his breadth of knowledge and lucid exposition being much appreciated by undergraduates. Research students remember him especially for his superb supervision, involving most carefuly designed experiments and thorough and questioning interpretation. It is no accident that, with this training, many of his postgraduates proceeded to Chairs or other senior

positions.

Besides his numerous contributions to plant physiology, Yemm collaborated in much research in plant ecology, in which he was keen to include precise experimentation alongside observational work. With JL Harley, a colleague from his Oxford days, he elucidated the peat formation and vegetation succession in a Yorkshire mire. Later investigations of the stratigraphy and history of the vegetation of the Gordano Valley, in north Somerset, unexpectedly revealed that the valley was by no means a detached part of the Somerset Levels, and the discovery of a completely hidden sandbar traversing the valley, formerly retaining a lake of Post-glacial age, is of much interest. Yemm's studies of coastal sites included the salt marsh at Berrow, near Burnham- on-Sea, where levels of salinity involving the rush Juncus subulatus, found here new to Britain, were in exact accord with its behaviour in the Mediterranean.

Yemm also promoted experimentation and ecophysiology at Braunton Burrows, North Devon; a striking finding here was the markedly domed nature of the water table, some 20 feet higher at the centre of this sand-dune system than at the periphery. Of present interest, in connection with global warming, is a study, started in 1958, of roadside vegetation near Bibury, Gloucestershire, in which Yemm played a leading part for some 30 years. Changes analysed in relation to climate are establishing the tolerances of species, which are now the subject of experimentation.

As a person Ted Yemm had much to be admired. His considerable modesty was known to all, as well as his reliability, fairness and integrity. Ever helpful to those in difficulties, he found time to talk to even the most junior staff, although this may have been behind a cloud of smoke from his beloved pipe. He was always most strongly supported by his wife, Marie, especially in retirement when he did much DIY, and also in their most attractive garden at Long Ashton.

(Photograph omitted)