Professor Enid MacRobbie (1931-2024) was a leading plant scientist, who dedicated more than six decades to exceptional research and teaching and mentoring future scientists at Girton College and the Department of Plant Sciences at the University of Cambridge.
Enid’s trailblazing work was at the forefront of plant ion transport studies, addressing fundamental questions in plant nutrition and cell signalling. She pioneered the use of radiotracers to measure ion fluxes, identified active and passive transport processes in giant algae, and elucidated transport mechanisms in stomatal movement. Throughout her career at Cambridge, she trained outstanding PhD students who went on to become influential scientists and made a lasting impact on the conditions for women in science.
Born in Edinburgh, Scotland, in 1931, Enid studied physics at the University of Edinburgh, earning a first-class BSc in 1953. She remained there for her PhD as the first graduate student in Jack Dainty’s biophysics research group, housed in a converted chicken house behind the Department of Genetics. Her thesis pioneered the use of radioisotopes to measure ion fluxes in plants, working initially with seaweeds before focusing on the giant alga Nitellopsis obtusa. She developed isotope efflux analysis, adapting an animal-cell technique to the complexities of plant cells with large central vacuoles. This groundbreaking work quickly established her reputation beyond Edinburgh.
After completing her PhD in 1957, Professor MacRobbie took up a postdoctoral position at the Institute of Biological Isotope Research in Copenhagen, studying ion transport in frog skin under Professor H. H. Ussing. One year later, in 1958, she secured a Research Fellowship at Girton College, University of Cambridge, working with Professor George Briggs in the Botany School (now Department of Plant Sciences).
Given the freedom to pursue her interests, she used isotopes to measure K+, Na+, and Cl- fluxes in the giant alga Nitella translucens. She aimed to determine which fluxes at the plasma membrane and tonoplast were active or passive and how they were regulated. This work enhanced her international reputation and helped establish a quantitative, biophysical approach to plant transport studies.
Enid’s research received a significant boost in 1964 when she, Jack Dainty (then at the University of East Anglia), and Charles Whittingham (Imperial College) secured a major five-year grant from the Nuffield Foundation. This allowed her to quickly build a research group and foster collaborations with talented Australian biophysicists, including Alex Hope, Alan Walker, and Geoff Findlay. The grant’s flexibility stood in stark contrast to the stringent conditions of modern funding.
Until the mid-1970s, her research focused on ion fluxes in giant algae, but in 1978, she shifted to studying stomatal guard cell movement—the key mechanism by which plants regulate gas exchange and water loss. The change stemmed from the realization that the ionic fluxes involved in stomatal opening and closing were poorly understood. Adapting her established methods, she secured funding in the early 1980s, and this research remained her primary focus. Her work has significantly advanced our understanding of stomatal control, complementing studies using techniques such as patch clamping.
Enid’s success in securing major research funding allowed her to take on PhD candidates in a supervisory capacity and supporting and mentoring young scientists became a tenant of her work in the years to come. Enid encouraged her researchers to publish without her name on their papers. Only about 25% of papers from her lab bear her name, meaning her contributions are significantly underestimated in citation metrics. This selfless approach boosted the careers of those she mentored, a rare practice in today’s citation-driven scientific environment. Her hands-on involvement in experiments continued throughout her career, and even after retiring in 1999, she remained active in the lab, performing flux measurements and mentoring younger colleagues.
Beyond research, Enid profoundly influenced Cambridge undergraduates, inspiring many to pursue science. Alongside Tom ap Rees, she modernised Cambridge’s botanical courses in the 1960s and 1970s, incorporating more cell biology, biochemistry, and quantitative analysis. She excelled in the small-group supervision system, leaving a lasting impact on students. Enid was a Fellow of Girton College from 1958 until 1999 when she was elected a Life Fellow, a position she held until her passing in 2024. Throughout her career, she played a key role in encouraging women to enter scientific careers, many of whom have since gained international recognition.
