Radioactive Contamination in Agriculture.
10:10-10:30 Prof Dr Em Frank Deconinck, BrIAS co-director, Vrije Universiteit Brussel, Belgium
Some facts and questions related to radioactivity
Radiocesium contamination of agrifood in Japan - Radiotracer studies for advancing plant nutrition knowledge
Effects of long term exposure of plants to radiation in nuclear accident affected areas: possible role DNA methylation in changes in plant development.
11:40-12:00 Prof Dr Ir Christian Hermans, Laboratory of Crop Production and Biostimulation, Brussels Bioengineering School, Université libre de Bruxelles, Belgium
Molecular and physiological targets of cesium toxicity in Arabidopsis
12.00-12.20 Samuele Guadagino, Plant Genetics, Bio-engineering Sciences, Vrije Universiteit Brussel (VUB)
The role of ectomycorrhizal fungi in pine adaptation and recovery
12:20-15:00 Break (onsite lunch and visit)
15:00-15:15 Floris Abrams, Biosphere Impact Studies, Belgian Nuclear Research Center (SCK CEN)
Towards more effective and efficient spatio-temporal schemes for remediation in Response to Large-Scale Nuclear Emergencies Affecting Food and Agriculture
15:15-15:30 Margot Van Heukelom, Biosphere Impact Studies, Belgian Nuclear Research Center (SCK CEN)
Predicting 137Cs bioavailability in agricultural soils on global scale
15:30-15:45 Serena Bordignon, Biosphere Impact Studies, Belgian Nuclear Research Center (SCK CEN)
Dose-rate and plant developmental-dependent responses to gamma radiation: do miRNAs play a role?
15:45-16:00 Brix De Rouck, Biosphere Impact Studies, Belgian Nuclear Research Center (SCK CEN)
Biological effects of chronic radiation exposure on pine trees
16:00-16:30 Closing remarks and networking
Natsuko Kobayashi, Laboratory of Radio Plant Physiology, Isotope Facility for Agricultural Education and Research, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan
The first part of the talk will be related to the Fukushima nuclear power plant accident. In March 2011, a powerful earthquake in Japan triggered a tsunami that caused severe damage to the nuclear plant complex of the Fukushima prefecture. As a result, radiocesium contamination suddenly became a serious concern for the agricultural sector. The Japanese government immediately set standards for radiocesium in food and extensive monitoring was undertaken. Identifying factors determining the degree of radiocesium contamination in agricultural products is key. This talk will focus on two main agricultural and horticultural products (rice and peach, respectively) in Fukushima. The surveys of the agrifood market in Japan during the last twelve years will be presented.
The second part of the talk will illustrate the use of radiotracers in plant nutrition research. Our facility at University of Tokyo allows using 55 radionuclides and it is fully equipped to carry experiments with plants. We have developed a real-time imaging system with intermittent illumination, as well as a micro-autoradiography technique using fresh frozen plant sections that does not require any chemical fixation. Our main research theme is on the characterization of the transport mechanisms of various elements (cadmium, cesium, magnesium, phosphorous, sodium …).
Nele Horemans1,Gustavo Turqueto Duarte1, Paulus Laanen Robin Nauts1, May Van Hees1, Sergey Gaschak2, Els Prinsen3, Vasyl Yoschenko4, Kenji Nanba4
1Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, B-2400 Mol, Belgium,
2Chornobyl Center for Nuclear Safety, Radioactive Waste and Radioecology, 07100 Slavutych, Ukraine
3University of Antwerp, Groenenborgerlaan 171, B-2610 Wilrijk, Belgium
4Institute of Environmental Radioactivity at Fukushima University, 1 Kanayagawa, Fukushima, 960-1296, Japan
E-mail contact: firstname.lastname@example.org
In this study the impact on plants of long-term exposure to radiation coming from nuclear accidents like Fukushima and Chernobyl is investigated and compared with lab experiments in either a chronic or acute exposures. The focus of the study was on whether changes in plant hormones and DNA methylation could be the basis of developmental and phenotypical differences found in field or lab conditions.
Field campaigns were performed in Chernobyl (CEZ, May 2016) and Fukushima affected areas (FEZ, May 2016, 2019, 2020). Annual Brassicacea plants and seeds, Arabidopsis thaliana and Capsella bursa pastoris in CEZ and FEZ, respectively, were sampled alongside a gradient of enhanced radiation ranging from 0.5 to 50 µGy.h-1. In addition needles of perennial Pinus densiflora trees showing abnormal phenotypic growth were sampled within FEZ at dose rates at 3 to 6 µGy.h-1. Seeds from Arabidopsis thaliana were harvested in the CEZ and grown for one clean generation under lab conditions to score for multigenerational effects and endophyte populations. In addition further lab experiments were performed on commercially available wild type plants of C. bursa pastoris and A. thaliana plantsgrown under chronic (at 1 mGy/h) or more acutely exposure conditions (14days, 20 to 400 mGy/h). Plants were scored for total DNA methylation and oxidative stress markers as well as developmental features such as germination rate, biomass accumulation and induction of flowering. Overall the data hint towards a role of methylation in the response to radiation but its use as marker of exposure or in risk assessment needs further experimental evidence and discussion.
This work was supported by European project COMET (Fission-2012-3.4.1-604794) (www.comet-radioecology.org)generation and by the Flemish Science foundation (FWO-Vlaanderen, VS01719N).
Christian Hermans, Laboratory of Crop Production and Biostimulation, Université libre de Bruxelles, Belgium
Molecular and physiological targets of cesium toxicity in Arabidopsis
Cesium is a rare element that has physical and chemical properties like that of potassium. The radiocesium produced by the development of civil and military nuclear engineering, raises environmental concerns. Long-lived radioisotopes enter the food chain via plants. This way, the mechanisms of absorption and transport of cesium by plants determine the degree of contamination of the food chain. The elucidation of these mechanisms is necessary to develop strategies to reduce radiocesium pollution in agricultural systems. Molecular and physiological targets of cesium toxicity were studied in the model plant Arabidopsis thaliana. Hydroponics culture system was employed to intoxicate plants with stable cesium. Concentrations greater than 0.50 mM quickly (within three days) caused the leaves in the center of the rosette to dry out, and inhibited plant growth. Concentrations below 0.10 mM had a beneficial effect on biomass production. The activity of photosystem II seems to be more rapidly impacted by cesium toxicity than that of photosystem I. Cesium increased in leaf and root tissues concomitantly. A rapid decrease in potassium concentration was observed in the roots, illustrating the competition of cesium on potassium transporters. A global transcriptomic analysis highlighted the early impact on the biosynthetic pathway of glucosinolates. These molecules are widely described in the defense against herbivores and pathogens. That fundamental knowledge opens prospects for developing strategies to mitigate the harmful effects of environmental contamination by radiocesium.