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In situ ageing of fine beech roots ( Fagus sylvatica ) assessed by transmission electron microscopy and electron energy loss spectroscopy: description of microsites and evolution of polyphenolic substances
Author(s) -
Watteau Françoise,
Villemin Geneviève,
Ghanbaja Jaafar,
Genet Patricia,
Pargney JeanClaude
Publication year - 2002
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/s0248-4900(02)01182-6
Subject(s) - beech , biology , fagus sylvatica , botany , mycorrhiza , ultrastructure , transmission electron microscopy , primordium , electron energy loss spectroscopy , biomineralization , biophysics , biochemistry , materials science , symbiosis , genetics , bacteria , gene , nanotechnology , paleontology
Root biomass is quantitatively and qualitatively important in most ecosystems, but its contribution to the pool of organic matter in the soil is not clear. This work was designed to specify root ageing on an ultrastructural scale by transmission electron microscopy combined with microanalysis by electron energy loss spectroscopy. This approach is very suitable for studying the soil/plant interface, and for semi‐quantitative analysis of the evolution of polyphenolic substances during root evolution. Three root segments were studied according to a gradient of root senescence: the apical and basal segments of the mycorrhiza and the mycorrhiza‐carrier root. Each segment contained a certain proportion of senescent cells, some of which were of fungal origin, and this proportion increased as the root aged. In the three segments, the soil/plant interfaces were differentiated, and the micro‐organisms observed in situ were described. Senescent root cells contained many polyphenolic substances and our results showed that these substances were, according to the root segment, differently associated with Ca, N and Si. When all these ultrastructural data are correlated with more global data, they can be usefully applied to root cell physiology, microbiology and pedology. This approach makes it possible to specify the evolution of organic matter in situ in soils whatever its origin.