Wiesel Lea, Dubchak Sergiy, Turnau Katarzyna, Broadley Martin R, White Philip J
The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK; School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK.
Institute of Environmental Sciences and Malopolska Centre for Biotechnology, Jagiellonian University, 30-387 Krakow, Poland.
J Environ Radioact. 2015 Mar;141:57-61. doi: 10.1016/j.jenvrad.2014.12.001. Epub 2014 Dec 23.
Contamination of soils with radioisotopes of caesium (Cs) is of concern because of their emissions of harmful β and γ radiation. Radiocaesium enters the food chain through vegetation and the intake of Cs can affect the health of organisms. Arbuscular mycorrhizal (AM) fungi form mutualistic symbioses with plants through colonization of the roots and previous studies on the influence of AM on Cs concentrations in plants have given inconsistent results. These studies did not investigate the influence of Cs on AM fungi and it is therefore not known if Cs has a direct effect on AM colonization. Here, we investigated whether Cs influences AM colonization and if this effect impacts on the influence of Rhizophagus intraradices on Cs accumulation by Medicago truncatula. M. truncatula was grown with or without R. intraradices in pots containing different concentrations of Cs. Here, we present the first evidence that colonization of plants by AM fungi can be negatively affected by increasing Cs concentrations in the soil. Mycorrhizal colonization had little effect on root or shoot Cs concentrations. In conclusion, the colonization by AM fungi is impaired by high Cs concentrations and this direct effect of soil Cs on AM colonization might explain the inconsistent results reported in literature that have shown increased, decreased or unaffected Cs concentrations in AM plants.
铯（Cs）的放射性同位素对土壤的污染令人担忧，因为它们会释放有害的β和γ辐射。放射性铯通过植被进入食物链，而铯的摄入会影响生物体的健康。丛枝菌根（AM）真菌通过根部定殖与植物形成互利共生关系，先前关于AM对植物中铯浓度影响的研究结果并不一致。这些研究没有调查铯对AM真菌的影响，因此尚不清楚铯是否对AM定殖有直接影响。在这里，我们研究了铯是否影响AM定殖，以及这种影响是否会对根内根孢囊霉对蒺藜苜蓿积累铯的影响产生作用。将蒺藜苜蓿种植在含有不同浓度铯的花盆中，有或没有根内根孢囊霉。在这里，我们提供了首个证据，表明土壤中铯浓度的增加会对AM真菌在植物上的定殖产生负面影响。菌根定殖对根或地上部的铯浓度影响很小。总之，高浓度的铯会损害AM真菌的定殖，土壤铯对AM定殖的这种直接影响可能解释了文献中报道的关于AM植物中铯浓度增加、降低或未受影响的不一致结果。
