Daphne Osborne

Born in India, where her father was a colonial administrator, Osborne attended The Perse School in Cambridge. Her BSc in chemistry and MSc in botany were from King's College London.[1] Her PhD on the topic of plant growth regulators was from the University of London at Wye College, Kent, where her supervisor was R. Louis Wain. Her first postgraduate position was in the Department of Biology of the California Institute of Technology, USA, as a Fulbright Scholar, where she worked with botanist Fritz Went, among others.[1][3]

Much of Osborne's career was spent at the Agricultural Research Council (ARC), later renamed the Agricultural and Food Research Council (AFRC). In 1952, she joined the ARC Unit of Experimental Agronomy at Oxford University, where she worked until the unit's closure in 1970. She then took up the position of deputy director at the new ARC Unit of Developmental Botany at the University of Cambridge.[1][3] During her time in Cambridge, she became the first female fellow of Churchill College and also supervised the college's first female PhD student.[3][6] After the unit's closure in 1978, she joined the AFRC Weed Research Organization at Begbroke just outside Oxford, where she worked until its closure in 1985, attaining the position of deputy chief scientific officer, a senior position in the British Civil Service.[3]

In 1985, Osborne retired from the Civil Service, and became a visiting professor at the Department of Plant Sciences of Oxford University, as well as an honorary research fellow of the Open University and of Somerville College, Oxford.[3] In 1991, she moved to the Oxford Research Unit of the Open University at Foxcombe Hall, Boars Hill, where she remained until her death in 2006. During her time at the Open University, she headed international research projects of the Royal Society, and also attracted funding from Unilever, the Wellcome Trust and the Biotechnology and Biological Sciences Research Council.[1][3]

Osborne travelled widely during her career, holding short-term positions at Princeton and the California Institute of Technology in the USA, and visiting Argentina, Australia, India, Israel, Malaysia, Nigeria and South Africa. She also formed many international collaborations, latterly with scientists in China and Ukraine.[1][3] In 1988, she organised a successful international NATO workshop in Turin, Italy.[3]

Ethylene, an important plant hormone

The hormonal control of growth, differentiation and development in plants was Osborne's lifelong interest. She is particularly known for her work establishing that the gas ethylene is a natural plant hormone, rather than a by-product or pollutant, and for demonstrating that ethylene, rather than abscisic acid, is the major regulator of senescence (ageing) and abscission (shedding of parts such as leaves).[1][3][7] She conducted extensive research into interactions between ethylene and auxin (another key plant hormone) in controlling numerous aspects of plant development. This work led her to develop the idea of the target cell as a model for how a small number of plant hormones can exert many different effects, a concept she expounded in her 2005 book, Hormones, Signals and Target Cells in Plant Development (co-authored with Michael McManus).[1][3][7]

African oil palm

Another major focus of Osborne's research was seed biology. An expert on seed ageing and plant DNA repair,[1] Osborne researched the effects of DNA degradation, repair and telomere length on the viability of seeds.[3] In the 1970s, she was among the earliest to attempt to isolate nucleic acids from ancient seeds, finding that only very short fragments could be isolated from grains from Egyptian tombs.[8] Among her final research projects was a study of the effects on DNA repair in seeds and pollen of exposure to radioactive fallout after the Chernobyl nuclear reactor explosion.[3][7]

Osborne studied a huge diversity of plant species, from the aquatic liverwort to the commercially important African oil palm. Other topics of research within plant science included auxin herbicides; dormancy in potato tubers; growth regulation in aquatic and semi-aquatic plants; linking plant ultrastructure with physiology and biochemistry; and protein and RNA synthesis in plants.[3] She was active in the field of space biology, designing a project for Spacelab studying the role of gravity on development in grass,[3] and serving on the Royal Society British National Committee on Space Research for a decade.[1]

She also worked on the effects of plant hormones on insects, showing that sexual maturity in desert locusts is regulated by gibberellins, so that eating withered vegetation low in gibberellins might prevent the insects becoming sexually mature during the dry season.[3][9]

Osborne was awarded an honorary professorship at Kiev University in the Ukraine in recognition of her research on the Chernobyl disaster, as well as an honorary research fellowship from Somerville College, Oxford. She received honorary doctorates from the UK's Open University and from the University of Natal, South Africa.[1][3][7] She was awarded the Sircar Memorial Gold Medal for Research in Physiology of the University of Calcutta in 1983.[1] She was elected a corresponding member of the Botanical Society of America in 1996.[10] In January 2008, a commemorative issue of the journal Annals of Botany was published in her honour.[11]