Environmental Plant Metabolism

My research aims to understand the control of plant respiratory metabolism under different latitudes to better model and predict the impact of environmental variabilities on ecosystem's aboveground respiration. My research combines theoretical and empirical approaches to disentangle the complexity of plant metabolic pathway. The empirical approach includes field measurements in temperate and sub-arctic deciduous forest as well as greenhouse environmental manipulation. The theoretical approach includes assessment of current Terrestrial ecosystems models' limitations and design and sensitivity-tests of new parameterizations for respiratory COproduction. 

Modeling Aboveground Plant Respiration

Understanding CO2/O2 respiratory fluxes in the light

Respiratory metabolism is divided in two fundamental parts: the electron transport chain for energy production and the tricarboxylic acid pathway (TCAP) (also known as Krebs cycle). When measuring net CO2 production using a classical gas exchange system (such as LI-6400), only decarboxylations through the TCAP can be measured. This project aims to design a new gas exchange system where both reactions could be measured at night but also in the day.

Role of photorespiration on respiratory metabolism

In C3 plants, photorespiration plays an important role in the primary metabolism of leaves. Evidences of its interaction with the respiratory metabolism has been shown. However the origin of this interaction and the environmental control of it remains unclear. This project aims to investigate the origin(s) and consequences of the interaction between photorespiration and respiration on respiratory and nitrogen metabolism in leaves on C3 plants.

Princeton University Python Community

Developing low-cost sensors for plant science

Biography

I joined Michael Bender's research team at Princeton University, in collaboration with Kevin Griffin from Columbia University, in December 2012. We developed a new technique, based on oxygen stable isotopes, to measure respiration in the light in plant leaves. 

My previous work at the Australian National University in Canberra, Australia was focussed on the effect of drought on respiration. To date, the impact of drought on respiration is still controversial as some studies report an increase, a decrease or no effect of drought on respiratory flux. This controversy becomes even more important when CO2 fertilization in a future world is added to the picture.

In 2010, I obtained a Ph. D in plant physiology at the University Paris Sud, France supervised by Guillaume Tcherkez. My thesis aimed to understand "The metabolic interactom between photosynthesis, (photo) respiration and nitrogen assimilation in C3 leaves". Carbon and Nitrogen metabolism are closely related and respiration seems to be the cornerstone of C:N balance inside leaves. As a consequence, G. Tcherkez and myself showed that TCA cycle is not "cyclic' in the light which is one of the reasons why respiration is inhibited in the light compared to dark respiration.

"Do all you can with what you have in the time you have in the place you are!" Xolani Nkosi