In the context of plant sciences, the design and construction of an instrument for full-field imaging of the synchrotron generated X-ray fluorescence emitted by a fully illuminated sample are presented. The aim is to produce a [2-14] keV achromatic X-ray microscope with a few micrometers spatial resolution, which does not need to scan the sample. Vastly used in high energy astronomy instruments, the only optics which fulfill this requirement in the X-ray regime are grazing incidence mirrors and coded apertures. We will present the two design processes investigated in parallel, as well as, fabrication and experimental results obtained on the development of this full-field fluorescence microscope.