2000-present: Senior Lecturer in Plant Biochemistry, University of Westminster
1992-2000: Research Associate in the Division of Biological Sciences at Lancaster University investigating the relationship between growth, turgor pressure and cell wall rheology in maize leaves and tomato fruit, including use of a single cell pressure probe.
1987-1991: Doctoral research into cell wall biochemistry and regulation of abscission into cell wall biochemistry and regulation of abscission at the School of Plant Sciences, University of Oxford (Linacre College).
Expertise: Plant cell wall biochemistry and biophysics, polymer rheology, plant water relations.
Stuart's main interest is in the relationships between plant cell wall biochemistry, plant cell wall mechanical behaviour and plant physiology. The internal turgor pressures in plant cells are generally very high (typically >0.5 MPa in well watered plants). The cell walls must contain these pressures but the interaction between pressure and tension in the wall is also critical in producing light flexible structures, such as leaves. This situation also presents plants with a problem, as for plant cells to grow the cell wall must become sufficiently plastic for cells to become larger without losing its structural integrity. His main research interest is how plants manipulate the chemical components of their cell walls in order to control their structural properties allowing cell expansion to occur in a controlled and regulated fashion.
Stuart's work is primarily based upon measurement of the biomechanical behaviour of growing plant tissues by creep extensiometry and examining the effect of different chemical, physical and enzymic treatments on the rate of extension. They are also using the Acetobacter xylinum to produce "artificial plant cell walls" as this bacterium produces cellulose microfibrils that resemble those found in plant cell walls.
These mechanical measurements have been interpreted using models from synthetic polymer rheology and this approach has generated a number of useful and novel insights into the behaviour of plant cell walls, including discovery of a completely new mechanism of growth inhibition under drought conditions.
Recent results have shown that the spacing between cellulose microfibrils and other cell wall components has a substantial effect on the mechanical properties in growing cell walls. This suggests that the water content of the wall has important effects on wall behaviour and therefore has implications for cell and plant physiology. We are currently investigating what wall components are involved in regulating cell wall spacing and water content, whether control of wall spacing is an element of growth regulation in vivo, and whether alteration of wall composition to maintain wall extensibility under conditions of low water availability is involved in adaptation to drought conditions.
- Cell wall "free volume" as a determinant of mechanical properties (plant physiology, plant cell wall biochemistry and biomechanical analysis).
- Production of composites of Gluconacetobacter cellulose with other biopolymers (culture of G. xylinum, biomechanical analysis, polymer synthesis and/or polysaccharide purification).
- The mechanism of trap closure Venus flytrap (cell wall biochemistry, plant physiology and water relations, biomechanical analysis).
- Cell wall mechanical behaviour and regulation of plant growth (cell wall biochemistry, enzyme and protein purification, biomechanical analysis).