TY - JOUR

T1 - Differences in arbuscular mycorrhizal colonisation influence cadmium uptake in plants

AU - Rask, Klara Andres

AU - Johansen, Jesper Liengaard

AU - Kjøller, Rasmus

AU - Ekelund, Flemming

PY - 2019

Y1 - 2019

N2 - Cadmium (Cd) is one of the most toxic heavy metals found in soil. Arbuscular mycorrhiza (AM) is known to reduce Cd translocation in plants by immobilising Cd in the root system. The effect of mycorrhiza on plant Cd uptake is usually studied in simple systems with single strains of mycorrhizal fungi and few levels of Cd. Here we studied how a wide range of soil Cd concentrations affected plant AM colonisation, and how the species-specific differences in AM colonisation affected uptake, translocation, and toxicity of Cd in plants in a system with naturally occurring mycorrhizal fungi. Six plant species were grown in pots in a greenhouse across seven levels of Cd, which made it possible to model dose-response curves, and calculate EC 50 for each plant species. We found a remarkable trend where Cd at moderate levels stimulated mycorrhizal colonisation until a certain threshold where the symbiosis breaks down. Our results support the existence of a protective effect of AM fungi against Cd, as the symbiosis reduces Cd translocation to shoots, especially in plants with very high AM colonisation. Thus, we conclude that it is the combination of plant species and AM colonisation that determines Cd uptake in plants. AM is therefore an essential trait to consider when growing plants in Cd-polluted soil.

AB - Cadmium (Cd) is one of the most toxic heavy metals found in soil. Arbuscular mycorrhiza (AM) is known to reduce Cd translocation in plants by immobilising Cd in the root system. The effect of mycorrhiza on plant Cd uptake is usually studied in simple systems with single strains of mycorrhizal fungi and few levels of Cd. Here we studied how a wide range of soil Cd concentrations affected plant AM colonisation, and how the species-specific differences in AM colonisation affected uptake, translocation, and toxicity of Cd in plants in a system with naturally occurring mycorrhizal fungi. Six plant species were grown in pots in a greenhouse across seven levels of Cd, which made it possible to model dose-response curves, and calculate EC 50 for each plant species. We found a remarkable trend where Cd at moderate levels stimulated mycorrhizal colonisation until a certain threshold where the symbiosis breaks down. Our results support the existence of a protective effect of AM fungi against Cd, as the symbiosis reduces Cd translocation to shoots, especially in plants with very high AM colonisation. Thus, we conclude that it is the combination of plant species and AM colonisation that determines Cd uptake in plants. AM is therefore an essential trait to consider when growing plants in Cd-polluted soil.

KW - Bio-accumulation

KW - Ecotoxicology

KW - Heavy metals

KW - Mycorrhiza

KW - Plant-microbe interactions

KW - Translocation factor

U2 - 10.1016/j.envexpbot.2019.02.022

DO - 10.1016/j.envexpbot.2019.02.022

M3 - Journal article

AN - SCOPUS:85062456878

VL - 162

SP - 223

EP - 229

JO - Environmental and Experimental Botany

JF - Environmental and Experimental Botany

SN - 0098-8472

ER -