The objective of this Master’s project was to develop new methods for plant histology and fluorescence imaging, useful to the Department of Plant Sciences at Geneva University (UNIGE). Seeds were chosen as a biological sample as they are challenging; a successful protocol could thus easily be adapted to other plant material. A biological inquiry was also investigated and the existence of potential symplastic domains in the endosperm of mature seeds was probed. In this context, two transgenic lines were generated: a sequestered (pABI5::NLS-2mVenus) and a freely diffusible reporter line (pABI5::mVenus). Comparing expression domains of mVenus in both lines will reveal how the endosperm’s chalazal, micropylar and peripheral regions are symplastically connected. The first methods investigated were High-pressure freezing and Freeze substitution, followed by in situ Correlative light and electron microscopy. Secondly, fluorescence microscopy was extensively explored, and different methods were experimented with, such as tert-Butanol-dehydration, Technovit 8100-embedding, clearing on section, immunofluorescence, serial sectioning, confocal and 2-Photon microscopy combined with Fluorescence lifetime imaging.