| Project Title |  |
| Project I2: Biomarkers
of metal exposure in terrestrial woody plants.
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| Research Team | |
| Ron R.H. Martin
(University of Western Ontario) - PI Email: rrhm@julian.uwo.ca Collaborator: Wilfried Rauser (University of Guelph)
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| Project Summary | |
| Phytochelatins will be assayed in foliage
of trees along a transect of expected decreasing historic deposition in the Sudbury
region, and evaluated as bioindicators of vegetation exposure to metals. The proportion of
foliar metal bound to phytochelatins will also be determined, as these complexes likely
represent reduced availability to metabolic sites. The historic movement of metals from
soil to foliage will be assayed by dendroanalysis of trees from the same historic
deposition gradient. The influence of soil remediation, by liming, on metal uptake by
vegetation will be assayed by sampling growth rings before and after soil amendment. The
proposed work is linked to other components of MITE, in that the data gathered for this
study will be from samples collected at the same sites as are described in P.1, so that
dendroanalysis and phytochelatins will be related to foliar tissue and soil metal
concentration. A Dendroanalysis as a historical record of metal phytoavailability. Martin Background. The analysis of trace element distribution in tree rings (dendroanalysis) is a promising approach to obtaining a record of environmental disturbance, in that it may provide a measure of the kinetics of element mobility in the environment. Some authors report excellent results while others are highly critical. Little is known of the mobility of metals in soil or within the tree ring system and thus if dendroanalysis is to be of any use, the data must be interpreted with the utmost caution. Dendroanalysis of trees in SW Ontario using Secondary Ion Mass Spectroscopy (SIMS) was consistent with the pollution history of each site. Current work suggests that specific elements may be more mobile than others in tree rings, and that some elements are highly localized; the exceptionally small areas that can be interrogated using SIMS makes this technique an effective tool for probing the detailed physiology of metal movement in trees.
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