Cadmium detoxification mechanisms in cacao tissues

The new EU regulation on cadmium (Cd) concentration in cocoa-derived products affects the cocoa market worldwide, especially in Latin-America, and requires the development of mitigation strategies. Plant breeding to produce low Cd-accumulating cocoa cultivars is one of them. However, this strategy requires a much better understanding and control of the physiological pathways of Cd uptake, translocation and accumulation in the beans. The various plant parts (root, branch, leaves and bean) of a cacao tree were sampled in the field and investigated in a combined approach (elemental analyses, Cd stable isotope analyses, bulk XANES spectroscopy and LA ICP MS imaging). We identified the branches and the leaves as the major storage compartments for Cd. To test their role as a sink, but also as a source of Cd for the bean, we wish to determine the Cd distribution and speciation in these tissues using µXRF and µXANES.