Graham Farquhar

This is my lab group outside the shed that formed our temporary accommodation in 2017. The photo was taken on the occasion of me winning the Kyoto award in 2017. Left to right: Victoria Allen, Hilary Stuart-Williams, Ross deans, Matthew Brookhouse, Florian Busch, me, Meisha Holloway-Phillips, Camille Bathellier, Diego Marquez and Chin Wong.

While my main interest lies in leaf water and gas exchange, my lab group changes and my research direction snakes its way through their strengths and interests!

At the moment a lot of my attention is taken up with Danielle Griffani’s research on water vapour exchange with leaves and the rate and nature of the water pools in them. Is all water in the leaf equally available for exchange with the environment or are some pools relative sealed off? What are the sizes of these pools and are they connected? Much of the experimental work consists of passing vapour of differing composition over plants and then examining the rate at which the leaf approaches equilibrium with the new vapour. The mathematics of this are fairly challenging and have excited my brain for some weeks!

Diego has been looking at gas exchange with leaves as well, with particular interest in comparing the vapour that emerges from the underside of the leaf and the upper surface (abaxial and adaxial respectively). Their characteristics are very different with much transport of water in the mesophyll as vapour which then escapes through numerous stomata in the lower surface. The upper surface has a waxy cuticle and few stomata so that water likely only evaporates from the upper cells of the leaf in very limited quantities. How is this reflected in the fractionations that occur?

Diego has also been using our new device for examining small quantities of water to map the oxygen and hydrogen isotopic composition of liquid in the leaf on a small scale. The data are based on a 5 mm grid and provide quite surprising insights into how water moves from the vascular system to the mesophyll. The images produced are likely to find themselves widely used in publications discussing leaf water isotopes!

For more information please jump across to my RSB page.

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