|Position in department||Member of Environmental and Plant Bioscience Research Group (Plant Productivity)
|Staff position||Reader in Plant Physiology
2015- present University of Essex, Colchester, UK
Reader -Plant and Algae Physiology
2015- 2015 University of Essex, Colchester, UK
Senior Lecturer -Plant and Algae Physiology
2014- 2015 University of Essex, Colchester, UK
Senior Research Fellow -Plant and Algae Physiology
2009- 2014 University of Essex, Colchester, UK
Research Fellow -Plant and Algae Physiology
2007- 2009 University of Essex, Colchester, UK
Permanent Senior Research Officer -Plant and Algae Physiology
2002-2003 Australian National University, Canberra, Australia
Visiting Research Fellow: Developing transgenic tobacco with altered guard cell metabolism
1999-2007 University of Essex, Colchester, UK
Senior Research Officer: Evaluating contributions of guard and mesophyll cell photosynthesis in the regulation of stomatal movements
1998-1999 University of Nottingham, Nottingham, UK
Postdoctoral Research Associate: Investigating the effects of changing climate and potential impacts on potato yield and quality (CHIP)
1997-1998 University of Dundee, Scotland, UK
Postdoctoral Research Assistant: Investigating soil microbial activity associated with buried archaeological material and the interactions between them
1993-1997 University of Dundee, Scotland, UK
PhD: Heterogeneity in Stomatal characters
1989-1993 Liverpool, John Moore's University, Liverpool, UK
BSc(Hons.) Applied Biology
Research Details: Stomatal physiology - Climate change and increasing global population is intensifying the need to find suitable crop plants for sustainable food and fuel production for future generations. Drought conditions and reduced water availability severely impact plant productivity and are considered a global threat to world food security. Stomata and their function therefore play a central role in determining the amount of carbon gained per unit water lost, known as plant “water use efficiency” and consequently have significant implications for crop yields, as well as global hydrological and carbon cycles. Stomata must ensure an appropriate balance between CO2 demands for photosynthesis and water loss through transpiration by correlating stomatal conductance with mesophyll photosynthetic rates. The underlying mechanisms and signals that promote this relationship are currently unknown. Stomata and photosynthesis respond to a number of environmental cues, however responses are not synchronized, with stomatal adjustments generally an order of magnitude slower than mesophyll responses. The resulting disconnection between stomatal conductance and photosynthetic rate means that under natural fluctuating environmental condition water use efficiency is most likely far from optimal. I am therefore interested in stomatal control of CO2 assimilation and the relation between mesophyll photosynthesis and stomatal behaviour and the signalling pathways that link these two fundamental processes. I also research the role of guard cell chloroplasts in stomatal function and how guard cell photosynthesis may provide a functional link between mesophyll photosynthesis and guard cell aperture.
Cyanobacterial physiology - Oceans play a major role in the global carbon cycle, with about 50% of the Earth’s photosynthesis each year occurring in aquatic marine environments, representing a major sink for atmospheric carbon dioxide (CO2). Primary productivity in many areas of the world’s oceans is limited by nitrogen and other nutrients such as phosphorous (P). Thus N2 fixing cyanobacteria including the dominant filamentous Trichodesmium are important in oligotrophic waters where they contribute the N that supports up to 50% of export production (Tyrrell et al., 2003; Capone et al., 2005). N2 fixation is an energy requiring process catalyzed by the enzyme nitrogenase, which is irreversibly damaged by molecular oxygen. Therefore, N2 fixing cyanobacteria must prevent nitrogenase from being damaged by molecular oxygen produced as a by-product of photosynthesis. Most diazotrophic cyanobacteria achieve this by separating photosynthesis and N2 fixation either spatially or temporally. Spatial separation is accomplished by conducting N2 fixation in specialized cells called heterocysts whilst temporal segregation relies on the use of respiratory energy to fix N2 at night. In contrast to these two strategies, the non-heterocyst cyanobacterium Trichodesmium executes both photosynthesis and N2 fixation during the light period without morphological differentiation of specialized cells. I am currently investigating the mechansims that allow photosynthesis and N2 fixation to occur simultaneously. I am also investigating the influence of elevated CO2 and nutrient limitation on photosynthetic processes and N2 fixation in two key cyanobacteria Trichodesmium and Crocosphaera.
Dr Silvere Vialet-Chabrand. POST DOCTORAL RESEARCH ASSISTANT. Stomatal-based systems analysis of water use efficiency. (BBSRC Standard Grant); in collaboration with M. Blatt (Glassgow) & H.Griffiths (Cambridge). 2014-2017.
Mr Jack Matthews - MPHD BIOLOGICAL SCIENCES Scaling up dynamic responses of stomata to assess impacts on tree canopy carbon gain and water use efficiency.(NERC Env East DTP studentship). .
Miss Kucheli Batta - PHD BIOLOGICAL SCIENCES. The role of guard cell chloroplasts in co-ordinating stomatal and mesophyll responses.
Mr Ifeanyi Oyemike - MPHD CELL AND MOLECULAR BIOLOGY. Manipulating Guard cell anatomy and physiology using biotechnological approaches to understanding impact on crop performance.
Mr Yazen Al-Salman - MSD ENVIRONMENTAL BIOLOGY
: Atmosphere-Biosphere co-evolution across geological time: The relationship between atmospheric carbon dioxide concentrations and plant hydraulic capacity.
Mr James Stevens - MPHD BIOLOGICAL SCIENCES Understanding water-use variation in elite barley varieties. (Funded by The Perry Foundation & School of Biological Sciences, University of Essex).
Mr John Stamford - MPhD Biological Sciences. Using spectral signatures as a toolbox for determining crop health status. (BBSRC Industrial Case Studentship, with industrial partners Environment Systems Ltd.).
Mr Matthew Keys - PHD MARINE BIOLOGY. Effect of future CO2, temperature and nutrient regimes on primary production in the Western English Channel.
Miss Laura Bretherton
- PHD MARINE BIOLOGY. The combined effect of daylength and CO2 on coccolithophore physiology
Co-supervised Research students:
Previously funded project:
· Ocean Acidification impacts on sea-surface biology, biogeochemistry and climate (NERC consortium PhD studentship); Co-Investigator Feb 2011-Jan 2014: PhD student - L. Bretherton
· A community metabolism approach to examine the environmental regulation of coral growth (NERC standard grant); Oct 2009-Sep 2012: Co-I Investigator PDRA - Dr D. Laing.
· Effect of light, CO2 and nutrient limitation on photosynthesis in marine diazotrophic cyanobacteria. (NERC standard grant). March 2008- August 2011. PDRA - Dr. M. Fryer.
· Establishing the mechanism(s) that enable stomata to respond to changing environmental cues, facilitating enhanced water use efficiency. (NERC quota studentship to Department of Biological Sciences). PhD student L. McAusland.
- Plant ecophysiology
- Electron transport and photosynthesis
- Stomatal physiology, control of gas exchange and carbon metabolism
- Plant growth and water use efficiency
- Effect of climate change on plant ecophysiology
- Interaction between plants and their microclimate
- Genetic manipulation of guard cell metabolism
- Chlorophyll fluorescence imaging
- Thermal imaging
- Algal/cyanobacterial physiology
- Photosynthesis and Nitrogen fixation
- Ocean acidification, including tecniques to measure carbonate chemistry
- Chlorophyll fluorescence
Contribute to teaching the following modules:
BS234 Plant molecular physiology and genetics
BS111 Plant Biology
BS707 Msc Tropical Marine Biology
|Publications||Link to publications for Tracy Lawson
Lab no: 5.36
Lab ext: 3726