The anthropogenic exploitation of heavy metals (HMs) has resulted in widespread contamination on a global scale. Nowhere is this more evident than in the Central Wales Orefield (CWO), where the historical extraction and processing of Zn-, Pb- and Cu-rich ores has led to long-lived contamination of watercourses and agriculturally valuable soils, with a concomitant decline in ecosystem health and resilience. The use of plants for the phytoremediation of polluted substrates offers a cheap alternative to costly heavy engineering solutions, but relies on the identification of species that have adopted either HM avoidance or HM tolerance strategies at a biomolecular level. This investigation seeks to build on previous hydroponic-based HM tolerance research into the performance of genotypes selected from a Lolium perenne (amenity x forage) mapping family. Two experiments used a growth medium comprising sand and dominantly monometallic Zn or Pb-rich tailings provenanced from two mines in the CWO. In each experiment, three specific treatments were applied; control, 10% and 30% by weight of tailings. In the two Zn treatments this equated to bioavailable substrate concentrations (ZnBA) of 1,890 μg g-1 and 5,670 μg g-1 and, in the two Pb treatments, to a PbBA of 445 μg g-1 and 1,335 μg g-1. A detailed analysis of the results reveals a wide variation, both within and between the two experiments, in genotype performance for traits including longevity, biomass production, tolerance index, HM uptake, tissue metal concentrations, and HM translocation. However, the phytostabilisation potential of certain genotypes in the L. perenne mapping family is confirmed. Individual genotypes are identified which, through poly- or pair-crossing, could provide the foundation for an elite, HM tolerant population with high potential for field-based testing on soils contaminated with Zn and Pb, as well as other HM species. MapQTL analysis facilitated the identification of numerous growth- and HM uptake-related QTL, possibly underlain by candidate genes for stress tolerance and HM transport, providing strong evidence both for pleiotropy and for the polygenetic control of these traits.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:715160 |
| Date | January 2016 |
| Creators | Mathews, Rosalind |
| Contributors | Macduff, James |
| Publisher | Aberystwyth University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/2160/7cbe8597-59c0-4413-905d-0840a5ef4025 |
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