Aluminum localization in the cell walls of the mature xylem of maple tree detected by elemental imaging using time-of-flight secondary ion mass spectrometry (TOF-SIMS)

摘要

The distribution of aluminum (Al) and other inorganic elements has been mapped at the cellular level in the mature xylem of maple by means of time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging. This method permits to image inorganic elements along with organic molecular species with high spatial resolution, and it was demonstrated that Na, K, Ca, and Mg are almost uniformly distributed in several contiguous growth rings of the air-dried wood sample. In contrast, Al was accumulated heterogeneously and intensely in the cell walls of the secondary xylem, including several growth rings, despite the long-term air-drying during storage. These results are interpreted that Al is immobilized within the cell wall, or it is closely interacted with the components of the secondary xylem. TOF-SIMS mapping also shows that Al has a tendency to be localized around vessels in the inner rings.