Trees in several regions of European Russia continue to feel the impact of the Chernobyl disaster.
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Although more than 30 years have passed since the accident at the Chernobyl nuclear power plant, we still do not know enough about how Chernobyl radioactive contamination affects plants. On the one hand, it is known that in plants, due to ionizing radiation, changes occur at the cellular level. But are these changes temporary, or can they affect the entire population? Will plants in contaminated areas become different over time from their counterparts in unpolluted areas?
One of the consequences of the accident was soil contamination with the radioactive cesium isotope 137Cs. Now “cesium” soils can be found in the west of the Bryansk region and in the Kaluga, Oryol and Tula regions. But in these same areas there are also territories unaffected by pollution. This proximity allows us to see how trees growing under the influence of radiation differ from their relatives. Stanislav Geraskin, Alla Udalova and their colleagues from the Research Institute of Radiology and Agroecology and the Obninsk Institute of Nuclear Energy MEPhI have been monitoring the condition of pine trees in the affected areas of the Bryansk region since the early 2000s. For nearly 13 years, researchers collected pine cones from several contaminated sites in late fall and compared the seeds to control samples from clean areas.
Experts germinated seed samples in laboratory conditions. And then they studied how much the cells in the root shoots mutated. In seeds from contaminated areas, disturbances in cell structure were more common, the authors explain in a publication in Environmental Pollution. The number of mutations of pure seeds changed rather slowly over time, sometimes increasing and sometimes decreasing. But in infected seeds this cycle was disrupted. Researchers observed a similar situation in the Leningrad region when they studied trees in areas with industrial pollution.
However, constant exposure to radiation did not affect the ability of pine seeds to germinate. Over time, disturbances in plant cells on contaminated lands become fewer. Most likely, this is due to a decrease in the amount of radionuclides in the soil.
The disruption of the rhythm in the appearance of mutations may be an adaptation of trees to radiation; however, whether this is true or not, further research will show. In addition, the authors of the work want to find out in the future how trees growing nearby synchronize the speed and frequency of mutations.