Cadmium phytoextraction potential of different Alyssum species

Our plain-English summary of Cadmium phytoextraction potential of different Alyssum species, by R. Barzanti, I. Colzi, M. Arnetoli, et al (Journal of Hazardous Materials, 2011).

The study

• Authors: R. Barzanti, I. Colzi, M. Arnetoli, A. Gallo, S. Pignattelli, R. Gabbrielli, C. Gonnelli
• Journal: Journal of Hazardous Materials
• Published: 2011;196:66-72
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This work was planned for providing useful information about the possibility of using serpentine adapted plants for phytoextraction of cadmium, element scarcely represented in such metalliferous environment. To this aim, we investigated variation in cadmium tolerance, accumulation and translocation in three Alyssum plants with different phenotypes: Alyssum bertolonii, that is a serpentine endemic nickel hyperaccumulator, and two populations of Alyssum montanum, one adapted and one not adapted to serpentine soils. Plants were hydroponically cultivated in presence of increasing concentrations of CdSO(4) for two weeks. For the metal concentration used in the experiments, the three different Alyssum populations showed variation in cadmium tolerance, accumulation and content. The serpentine adapted population of A. montanum showed statistically higher cadmium tolerance and accumulation than A. bertolonii and the population of A. montanum not adapted to serpentine soil thus deserving to be investigated for phytoextraction purposes. Furthermore, as for the kinetic parameters of the cadmium uptake system, A. montanum serpentine population presented a low apparent K(m) value, suggesting a high affinity for this metal of its uptake system, whereas the V(max) values were not significantly different among the plants. Present data revealed metallicolous plants are also suitable for the phytoremediation of metals underrepresented in the environment of their initial origin. Nonetheless, field trials on real contaminated soils are essential.

Copyright © 2011 Elsevier B.V. All rights reserved.

In plain English

This Italian laboratory study asked whether serpentine-adapted plants could take up cadmium, a metal scarce in serpentine soils. It did not study asbestos or human health effects, though the authors call cadmium extremely toxic to human health. It compared the nickel hyperaccumulator Alyssum bertolonii, from serpentine soil, with Alyssum montanum from serpentine soil at Monterufoli and from normal soil. Seedlings grew in solutions of 0 to 10 µM cadmium sulfate. Growth fell in all three as cadmium rose. Serpentine A. montanum had the highest root tolerance (EC50 1.86 µM) and A. bertolonii the lowest (0.97 µM); only this difference was statistically significant. Intact A. bertolonii seedlings had the highest root cadmium concentration except at the lowest dose. In one-hour tests its cut roots took up the least cadmium at most concentrations. At 2 and 5 µM it had the lowest shoot cadmium concentration. Serpentine A. montanum had the highest shoot-to-root concentration ratio (0.81), significantly above A. bertolonii (0.32) but not the other A. montanum (0.60). The authors concluded this population merits further phytoextraction study, but that work on real contaminated soils is needed.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory hydroponic experiment on plants, with metal analysis of field-collected plants and short-term uptake tests in excised roots
• Who was studied: Three Alyssum plant populations from Italy: Alyssum bertolonii from a serpentine outcrop at Pieve Santo Stefano (PSS); Alyssum montanum from a serpentine outcrop at Monterufoli (MR) and from normal soil at Monte Prata (MP). Ten adult field plants per population were analysed, and 30 plantlets per treatment were measured for growth.
• Exposure: Cadmium, which the authors describe as extremely toxic to living organisms and human health, given as cadmium sulfate (CdSO4) in hydroponic solution at 0, 0.25, 0.5, 1, 2, 5 and 10 µM for 11 days. Excised roots were exposed to 0 to 5 µM for 1 hour. No asbestos or fibers were studied.
• Main results:
  • In field-collected plants, A. bertolonii had the highest nickel concentrations, far higher in shoots (7040 ± 1036 µg/g dry weight) than in roots (396 ± 38). Only small amounts of cadmium were found in all three populations.
  • All three populations showed reduced root and shoot growth as cadmium concentration increased.
  • Root cadmium tolerance (EC50, µM CdSO4) was highest in A. montanum MR (1.86 ± 0.36), then A. montanum MP (1.57 ± 0.33), then A. bertolonii PSS (0.97 ± 0.19). Only the difference between PSS and MR was statistically significant (p less than 0.05). MP did not differ significantly from either.
  • The authors reported that, on the tolerance indexes, A. bertolonii was significantly more sensitive than the serpentine A. montanum, while the two A. montanum populations did not differ in cadmium tolerance.
  • In intact seedlings, root cadmium concentrations were highest in A. bertolonii PSS, then A. montanum MP, then A. montanum MR, at every exposure except the lowest.
  • Shoot cadmium concentrations differed among populations only at the two highest exposure levels in the accumulation experiment (2 and 5 µM). At those levels A. bertolonii PSS had the lowest values and A. montanum MR the highest.
  • The shoot-to-root cadmium concentration ratio was estimated from a regression line. It was 0.32 ± 0.05 in A. bertolonii PSS, 0.60 ± 0.15 in A. montanum MP and 0.81 ± 0.18 in A. montanum MR. The only significant difference was between PSS and MR (p less than 0.05).
  • In the one-hour excised-root experiment, A. bertolonii showed the lowest root cadmium concentrations at most of the concentrations used.
  • In excised roots, the apparent Km of cadmium uptake was higher in A. bertolonii PSS (4.77 ± 0.86) than in A. montanum MR (1.84 ± 0.29; p less than 0.001). Vmax did not differ significantly among the three plants.
• The authors' conclusion: The authors concluded that, compared with non-serpentine A. montanum and the nickel hyperaccumulator A. bertolonii, the serpentine-adapted A. montanum population showed cadmium tolerance and accumulation that merit further study for phytoremediation.
• Limitations the authors state:
  • The authors stated that studies of plants grown on real contaminated soils are needed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Serpentine Group, Translocation, Endemic.

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