Department of Plant Sciences

Current research

1. Stable Isotopes

  carbon uptake Fractionation during carbon uptake, (photo)respiration and carbon export drives the bulk organic signal in individual leaves to change by as much as 3 per mille per growing season, and , depending on climatic conditions, carbon exported from shoots to roots drives soil respiratory processes.

Links:
PhD Project.
Carbon Balance of Forest Biomes

The natural abundances of 13C and 18O are natural markers of biological transformations and provide a key to the evaluation of climate change processes, in terms of carbon sequestration and exchanges between soils, vegetation and the atmosphere. delta13C measurements provide insights into photosynthetic pathway, water use and soil respiration in the terrestrial environment, and carbon acquisition mechanisms by aquatic plants. d18O can be used to explore plant evaporative exchanges or water sources, or respiratory sources of CO2.


2. Photosynthetic CO2 concentrating mechanisms (CAM, C4 and the biophysical CCM in algae and bryophytes)

A range of mechanisms have co-evolved in response to various selective pressures, but Crassulacean Acid Metabolism (CAM) remains the ultimate lesson in physiological plasticity in form and function. CAM provides insights for the molecular and circadian co-regulation of carboxylases (Rubisco and PEPC), as on a daily basis, the range leaf internal CO2 concentrations exceed those experienced throughout palaeohistory. The operation of the differing CCMs in natural vegetation provides ecological insights into climate change for tropical epiphytes, their water sources and evaporative exchanges (e.g. bromeliads, ferns, bryophytes and lichens). With the development of modern molecular phylogenies, we are evaluating the selective pressures and molecular physiology of carbon concentrating mechanisms in groups ranging from C3 - CAM intermediates to algae with pyrenoids.


3. Ongoing research themes:

(i) Stable Isotopes

  1. Isotopic discrimination during C4 photosynthesis as a proxy to study the biochemical limitations (Chandra Bellasio)
  2. carbon allocation and biomass partitioning in Maize and Miscanthus crop canopies (Wanne Kromdijk, Hans Schepers)
  3. scaling fractionation from photosynthetic and (photo)respiratory metabolism and water use from leaf to canopy (Ulli Seibt, Gary Lanigan, Nick Betson, Joel Dunn, Glyn Jones);
  4. distribution and diversity in epiphytes: bromeliads, ferns and bryophytes as markers of climatic gradients and climate change (Aline Horwath, Monica Mejia-Chang, Casandra Reyes-Garcia, Yasmin Baksh-Comeau, Jan Wolf)
  5. high resolution record of Holocene climate and vegetation from antartic moss (Jessica Royles) (add link)
  6. the genetic basis to drought tolerance in sugar beet (Abazar Rajabi, Wanne Kromdijk)
  7. soil respiration and carbon balance of tropical soils (Andew Nottingham)
  8. competition and vegetation dynamics in arid ecosystems (Mohammad Jankju)
  9. isotopic landscapes and modelling isotopologies (Wanne Kromdijk, Guillaume Tcherkez)
  10. water sources and global partitioning of water use and precipitation (MIBA, IAEA)

(ii) Carbon Concentrating Mechanisms

  1. chloroplast pyrenoid: molecular physiology, structure and function (Moritz Meyer)
  2. Energetics of C4 photosynthesis under low light conditions (Chandra Bellasio)
  3. Interactions between Rubisco and PEPc during the CAM cycle (Barney Davies)
  4. Modelling gas exchange and stomatal limitations (Howard Griffiths, Susanne von Caemmerer)
  5. Use of stable isotopes to evaluate photosynthetic carbon uptake mechanisms in aquatic plants (Melissa Barratt)
  6. Molecular physiology of the chloroplast pyrenoid in bryophtes (Moritz Meyer)
  7. Distribution of C3 and CAM bromeliads in tropical ecosystems (Monica Mejia-Chang, Casandra Reyes-Garcia)
  8. Molecular phylogeny of CAM in contrasting plant groups (Howard Griffiths)