Multiple environmental factors influence 238U, 232Th and 226Ra bioaccumulation in arbuscular mycorrhizal-associated plants.
Multiple environmental factors influence 238U, 232Th and 226Ra bioaccumulation in arbuscular mycorrhizal-associated plants.
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DOI：
10.1016/j.scitotenv.2018.05.370
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发表时间：
2018-11
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影响因子：
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通讯作者：
Helena S. Davies;Jeanette Rosas-Moreno;Filipa Cox;P. Lythgoe;A. Bewsher;F. Livens;C. Robinson;J. Pittman
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文献类型：
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作者：
Helena S. Davies;Jeanette Rosas-Moreno;Filipa Cox;P. Lythgoe;A. Bewsher;F. Livens;C. Robinson;J. Pittman
了解自然资源或放射性废物的低剂量放射性的生态后果很重要，但知识差距仍然存在。特别是，放射性核素在土壤中的转移和生物累积到植物根部的研究很少。此外，更好地了解丛枝菌根（AM）真菌关联可能有助于理解根际放射性核素生物累积的复杂性。两个现场证实了铀、钍和镭的植物生物富集，植物组织浓度分别达到46.93μgg−1 238U、0.67μgg−1 232Th和18.27kBqkg−1 226Ra。在所有研究的植物物种中，铀的根部保留率较高。相比之下，大多数植物的钍和镭在地上组织中的生物累积程度更高。研究了特定土壤参数对根部放射性核素生物累积的影响。总有机碳显着解释了根部铀浓度的变化，而其他土壤因子，包括铜浓度、镁浓度和pH值，分别与根部铀、镭和钍浓度显着相关。球囊菌门的所有四个目都与两个地点的根部样本相关，并且研究的所有植物物种都显示出与 AM 真菌的不同关联，真菌丛枝根部定植的范围从零到>60%。先前利用单一植物-真菌物种关联的实验室研究发现AM真菌在根部铀转移中具有积极作用，但此处未发现真菌感染量与田间样品中根部铀含量之间存在显着相关性。然而，AM真菌感染与镭积累之间存在显着负相关。这项研究首次探讨了 AM 真菌在自然环境中群落水平的放射性核素土壤-植物转移中的作用。我们的结论是，生物因素与各种非生物因素一起影响放射性核素的土壤-植物转移，需要未来的机制研究来更详细地解释这些相互作用。
Ecological consequences of low-dose radioactivity from natural sources or radioactive waste are important to understand but knowledge gaps still remain. In particular, the soil transfer and bioaccumulation of radionuclides into plant roots is poorly studied. Furthermore, better knowledge of arbuscular mycorrhizal (AM) fungi association may help understand the complexities of radionuclide bioaccumulation within the rhizosphere. Plant bioaccumulation of uranium, thorium and radium was demonstrated at two field sites, where plant tissue concentrations reached up to 46.93 μg g−1 238U, 0.67 μg g−1 232Th and 18.27 kBq kg−1 226Ra. High root retention of uranium was consistent in all plant species studied. In contrast, most plants showed greater bioaccumulation of thorium and radium into above-ground tissues. The influence of specific soil parameters on root radionuclide bioaccumulation was examined. Total organic carbon significantly explained the variation in root uranium concentration, while other soil factors including copper concentration, magnesium concentration and pH significantly correlated with root concentrations of uranium, radium and thorium, respectively. All four orders of Glomeromycota were associated with root samples from both sites and all plant species studied showed varying association with AM fungi, ranging from zero to >60% root colonisation by fungal arbuscules. Previous laboratory studies using single plant-fungal species association had found a positive role of AM fungi in root uranium transfer, but no significant correlation between the amount of fungal infection and root uranium content in the field samples was found here. However, there was a significant negative correlation between AM fungal infection and radium accumulation. This study is the first to examine the role of AM fungi in radionuclide soil-plant transfer at a community level within the natural environment. We conclude that biotic factors alongside various abiotic factors influence the soil-plant transfer of radionuclides and future mechanistic studies are needed to explain these interactions in more detail.