Our research is focused on understanding plant metabolism, mostly using stable isotopes (¹³C, ¹⁵N, ³³S) and metabolomics. We use both natural isotope abundance and isotopic labelling to shed light on metabolic fluxes and interactions between metabolic pathways. Plant leaves have competing metabolisms occurring at the same time (photosynthesis, photorespiration, mitochondrial respiration, nitrogen and sulphur assimilation) but the means by which they are reconciled and orchestrated within plant cells is hardly documented.