Howard Griffiths is accepting applications for PhD students.
University of Cambridge
Cambridge CB2 3EA
2002-present: Fellow of Clare College, Cambridge.
2003: Joint organiser BES/SEB International Symposium 'Carbon Balance of Forest Biomes'
2004: Chairman/Discussion leader, International Photosynthesis Congress, Montreal
2005: Organiser: SEB Barcelona (Drought tolerance); IBC Vienna (Epiphytes and climate change); Discussion leader, Gordon Conference, Aussois, France;
2006: Visiting Research Fellow, RSBS, Canberra
2007: Organiser, C4-CAM satellite meeting to International photosynthesis congress
2007: Member, NERC Peer Review College
2008: Visiting Research Fellow, RSBS, Canberra
1981, 1983, 1985,1990, 1992, 1995, 1998, 2003, 2004-: Leader of expeditions for field work in Trinidad, Venezuela and Panama using stable isotopes to investigate carbon balance, drought tolerance and water vapour exchanges for forests and epiphytes.
Stable isotopes and coupling of carbon and hydrological cycles
Stable isotopes provide non-invasive biological and ecological markers of metabolic and atmospheric transformations of water and carbon dioxide, coupling plant carbon uptake and sequestration into biomass as a function of water availability and use (Griffiths & Jarvis 2005; Griffiths et al 2000; Tcherkez et al. 2007). We are evaluating plant growth under marginal habitats for the selection of drought tolerant cultivars and perennial biomass crops, such as Miscanthus, and their impact on canopy water use. Armed with a framework of quantitative models which allow plant gas exchanges to be modelled from the scale of leaf to crop (or forest) canopy, we can partition 13C/12C and 18O/16O to reveal net carbon sequestration over a plantation crop, as a function of soil respiratory losses. We use real-time, dynamic models of stable isotopes to monitor such exchanges (Tcherkez et al. 2007; Kromdijk et al 2008). Furthermore, with for every 3 CO2 entering a leaf, 2 retro-diffuse to create an isotopic imprint in atmospheric CO2, then the equivalent inward flux of water vapour must be 10 or 100 times greater at high humidity: Helliker and Griffiths, 2007) . Finally, an enduring interest in carbon concentrating mechanisms (CAM (Griffiths et al 2007), C4 (Marshall et al 2007), and the biophysical CCM in algae, cyanobacteria, lichens and hornworts has led us to investigate the structure, function and molecular basis to the chloroplast pyrenoid (Meyer et al 2008).
The focus of our recent work has been in the following key areas which integrate carbon partitioning and water use:
- scaling fractionation from photosynthetic and (photo)respiratory metabolism and water use; eddy flux partitioning and coupling of Miscanthus crop canopy CO2 exchanges (Wanne, see Kromdijk et al 2008)
- systems biology concepts for modelling isotopic landscapes and isotopomics (Tcherkez et al 2007);
- stable isotopic markers and the genetic basis to drought tolerance in brassicas, maize and sugar beet (Abazar, see Rajabi et al 2007; Hall et al 2005; Price et al 2002)
- Chloroplast pyrenoid: molecular definition of an enigmatic organelle (Moritz, see Meyer et al, 2008)
- soil respiration and carbon balance of tropical soils; plant competition and vegetation dynamics (Jankju-Borzelabad and Griffiths 2006) ;
- hydrology of tropical epiphytes and cloudforest formations: markers of climatic gradients (Helliker and Griffiths, 2007; Reyes-Garcia et al 2008, in review) see Aline Horwath;
- photosynthetic and oxidative interplay between chloroplast and mitochondria (Changfang Zhou, see also Janneke Balke)
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