Localization and characterization by electron energy loss spectroscopy (EELS) of the brown cellular substances of beech roots

Degradation of roots from beech trees was investigated by a novel approach: localization and elemental characterization of predominant brown substances were performed at ultrastructural scale using electron energy loss spectroscopy (EELS). This technique allowed us to detect light elements such as C and N, main constituents concerned in the degradation of plant tissues, within cellular constituents observed with a transmission electronic microscope, after having localized them by light microscopy. The results showed that there was no relationship between the brown pigmentation of the cellular substances and the presence of N, a relationship previously found in studies of degrading leaves. Other elements such as Si and Ca were also found to be involved in these root degradation processes. This approach seem powerful for detailed descriptions of the process of root degradation in soil.