Techniques developed

Thermal Imagery

Dynamic Leaf Energy Balance

The aim of this technique was to rethink the current methodology surrounding the processing of thermograms and derive temporal responses of stomatal conductance using dynamic energy balance equations.
  • Time-series thermograms provide the basis for a spatial and temporal characterisation of stomatal conductance responses.
  • A leaf replica with known conductance is used to validate the approach and to test the ability of the model to be used with any material and under any environmental condition.
  • Results from this technique highlight the importance of co-ordinated stomatal responses that run parallel to the leaf blade despite stomatal patchy distribution. Furthermore, through analysing the diversity and asymmetry of the temporal response of stomatal conductance, we can interpret the strategies being employed by plants to maximize photosynthesis and avoid heat stress in response to light flecks in a natural environment.
  • This techniques removes a major bottleneck for plant phenotyping platforms and will pave the way to further developments in our understanding of stomatal behaviour. 
Publication
​Vialet-Chabrand, S. and Lawson, T. (2019). Dynamic leaf energy balance: deriving stomatal conductance from thermal imaging in a dynamic environment. Journal of experimental botany. 70(10), pp.2839-2855

Dual thermal-fluorescence Imager

Imaging of Intrinsic Water-Use Efficiency

Instrumentation and methods for rapid screening and selection of plants with improved water use efficiency are essential to address current issues of global food and fuel security. We developed a new imaging system that combines chlorophyll fluorescence and thermal imagery to generate images of carbon assimilation rate, stomatal conductance, and intrinsic water use efficiency from leaves and even whole plants, under controlled environmental conditions. 
  • This is the first demonstration of the production of images of water use efficiency (WUEi) and the first to determine images of stomatal conductance from themography at the whole-plant scale.
  • The system can be used to rapidly and non-destructively screen plants for alterations in carbon assimilation rate (A), stomatal conductance (gs), and WUEi. 
  • This novel instrument not only provides the potential to monitor multiple plants simultaneously, but enables intra- and interspecies variation to be taken into account both spatially and temporally.  Whilst the ability to measure A, gs, and WUEi progressively was developed to facilitate and encourage the development of new dynamic protocols. ​
Publication
​McAusland L, Davey PA, Kanwal N, Baker NR, Lawson T. 2013. A novel system for spatial and temporal imaging of intrinsic plant water use. Journal of Experimental Botany. 64: 4993-5007