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| Titel |
On the metal tolerance and resilience capacity of Helichrysum italicum G.
Don growing on mine soils |
| VerfasserIn |
Laura Maleci, Corrado Tani, Claudio Bini, Mohammad Wahsha |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250124665
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| Publikation (Nr.) |
 EGU/EGU2016-4138.pdf |
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| Zusammenfassung |
| Abstract
Heavy metal accumulation produces significant physiological and biochemical responses
in vascular plants. Plants growing on abandoned mine sites are of particular interest, since
they are genetically tolerant to high metal concentrations. In this work we examined the
effects of heavy metals (HM) on the morphology of Helichrysum italicum growing on mine
soils, with the following objectives:
to determine the fate of HM within the soil-plant system;
to highlight morphological modifications at anatomical and cytological level;
to ascertain the plant tolerance to heavy metals, and their resilience capacity.
Wild specimens of Helichrysum italicum, with their soil clod, were gathered from sites with
different contamination levels by heavy metals (Cd, Cu, Fe, Pb, Zn) in the abandoned
Niccioleta mine (Tuscany, Italy). Plants were brought to the botanical laboratory of the
University of Florence, and appeared macroscopically not affected by toxic signals (e.g.
reduced growth, leaf necrosis) induced by soil HM concentration. Leaves and roots taken at
the same growing season were observed by light microscopy (LM) and transmission electron
microscopy (TEM).
Light microscopy observations show a clear difference in the cell organization of
not-contaminated and contaminated samples. In particular, the secreting trichomes, which are
responsible for the characteristic flavour of the plant, present a different morphology in the
polluted specimens with respect to the not-polluted ones. Indeed, the latter present the typical
trichomes of the Asteraceae family, with two lines of cells bearing the secretion accumulated
on the apical cuticular space. Trichomes of the polluted plants, instead, present a completely
different morphology, with a stalk of 3-4 cells and a large secreting apical cell (i.e. they are
capitate hairs).
Samples from contaminated sites, moreover, present a palisade parenchyma less
organized, and a reduction of leaf thickness proportional to HM concentration. The poor
structural organisations, and the reduced foliar thickness of the contaminated plants, are
related to soil contamination.
A gradual restoration of cell organization suggests that somewhat resilience occurred in
plants. Moreover, the presence of stress-tolerant mycorrhizal fungi could contribute to reduce
metal toxicity. The resilience capacity suggests that Helichrysum italicum could be a useful
species in remediation projects.
Keywords: Heavy metals Mine soils Plant morphology Helichrysum italicum
Ultrastructure |
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