Production of concentrated polyphenols by the root cap cells ofCorylus associated withTuber: ultrastructural study and element localization using electron energy loss spectroscopy and imaging

In mycorrhizae, root cap cell differentiation is a rapid event. Dark deposits abruptly invade the cytoplasm and the vacuoles. Finally the vacuoles fill with phenolic deposits and the cytoplasm is moribund. After degradation of the cell wall and cytoplasm, hyphae make contact with polyphenols and penetrate the polyphenols. The polyphenols are incorporated into the fungal mantle. Microanalysis by means of an electron-energy-loss spectrometer (EELS) and an electron imaging system (ESI) reveals the presence of calcium and nitrogen in the polyphenolic material just incorporated into the apical mantle. More distant polyphenols no longer contain calcium but nitrogen is still locally present.