Contrasting behaviour of cadmium and zinc in a soil–plant–arthropod system

The transfer and fate of Pb from sewage sludge amended soil in a multi-trophic food chain: a comparison with the labile elements Cd and Zn

“…Consequently, they can exert a modicum of control over the accumulation of Cd. Nevertheless, the contrast in results between the present study and that of Crawford et al (1995) and Green et al (2006) suggests that regulation of Cd by this mechanism may not apply to all aphid species.…”

“…It has been suggested that aphids exert little control over their uptake of Cd (Crawford et al 1995) and that Cd concentration in the shoot is the predominant factor determining Cd concentration in aphids (Green et al 2006). It is apparent that if the plant restricts transfer of Cd to the shoot, then transfer through the higher trophic levels of the food chain must also be restricted, as seen in the case of Zn in the present study.…”

“…the plants restricted the loading of Zn into the phloem sap. This contrasts to work investigating the transfer of Zn from the shoots of cereal plants to aphids, which found a linear relationship between shoot and aphid Zn concentration (Green et al 2006). …”

Heathland Restoration on Former Agricultural Land: Effects of Artificial Acidification on the Availability and Uptake of Toxic Metal Cations

“…The lack of an association between the concentration of Cd extracted from soil by a neutral salt and the concentration in plant shoots is at variance with the findings of other studies (Häni & Gupta, 1984;Sauerbeck & Stypereck, 1984;Mellum, Arnesen, & Singh, 1998). Whilst the concentration of Cd in plant roots may reflect the extractable concentration in the soil, this may not hold true for the shoots because restricted translocation within the plant can result in a non-linear relationship between root and shoot concentration (Salt et al, 1995;Hamon et al, 1999;Green, Jeffries, Diaz, & Tibbett, 2006). This mechanism may have mediated the effect of increased extractable Cd in the soil and prevented Cd transfer to higher trophic levels.…”

Potentially Toxic Metals in Historic Landfill Sites: Implications for Grazing Animals

“…Secondly, animals can also be exposed to pollutants taken up from the soil by plants, which are subsequently translocated to the shoots. Although the root-shoot barrier generally excludes PTMs from the shoot, this is not always the case and PTM concentrations higher than in the soil may be found in shoots (Sauerbeck, 1991;Green et al, 2006). Consequently, there can be elevated concentrations of PTMs in the shoots of plants growing on landfills (Murphy et al, 2000;Hernández et al, 2012).…”