Protonic conductivity in seeds has been studied by means of broad-band dielectric relaxation spectroscopy and of various techniques of thermally stimulated currents over wide ranges of water contents, temperature and frequency. Results are discussed in terms of percolative proton transfer along threads of hydrogen-bonded water molecules and of a glass transition occurring in the seed constituents, and in relation to the emergence of biological functions in seeds. The work proposes, moreover, an alternative non-destructive method for the determination of water content in biological materials.