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Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

 Федеральный исследовательский центр «Красноярский научный центр Сибирского отделения Российской академии наук»

Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

Siberian scientists have established that small doses of radiation damage the DNA of onion seedlings

23 April 2020 г.

Сибирские ученые установили: малые дозы радиации повреждают ДНК проростков семян лука
Specialists of FRC "Krasnoyarsk Science Center SB RAS" and FRC "Institute of Cytology and Genetics SB RAS" have investigated the effect of gamma radiation on the degree of DNA damage of onion seedlings. By comparing DNA parameters of the plant with the control samples, scientists have found that even small doses of radiation can lead to various chromosomal abnormalities, while previously it was believed that only large doses could produce similar effects. Experiments on the irradiation of seedlings were carried out in the radiation research department at the G. I. Budker Institute of Nuclear Physics SB RAS. The results of the study are published in the journal "Reports of the Academy of Sciences" and Journal of Environmental Radioactivity.

The effect of large doses of radiation on humans and living organisms has been studied in sufficient detail. To a lesser extent, the patterns of action of small radiation doses are understood. The International Commission on Radiation Protection adopted the so-called linear non-threshold model, according to which the negative effects of radiation are manifested even at low doses. To date, quite a lot of data has been accumulated which contradict this hypothesis. Therefore, experts have also developed a threshold model. It implies that small doses of radiation do not have a negative effect, but with the increasing doses, the effects appear spasmodically, after passing a certain threshold, which is individual for each living organism.

A team of Siberian scientists investigated how different doses of gamma radiation affect the degree of DNA damage of onion seedlings. Scientists recorded DNA damage of seedlings which received small doses of radiation (0.02 - 0.1 Gy). It was also found that in the range of doses greater than 0.02 Gy, the number of injuries increased almost linearly, however, the growth stopped when the radiation dose increased above 1 Gy, and even a decrease in the level of damage was observed. Therefore, scientists can speak of a dose-independent plateau in the dose range from 1 up to 5 Gy.

According to the head of the Laboratory of Radioecology of the Institute of Biophysics KSC SB RAS, Doctor of Biological Sciences, Alexander Bolsunovsky, this effect can be explained by the existence of a damage threshold. Small doses of radiation cause a relatively small damage to the cells, therefore, the repair mechanism starts only when the amount of damage reaches a certain critical point. It should be noted that in such a situation there is a risk of incorrect repair of DNA breaks, and this can lead to serious chromosomal abnormalities, which can manifest only in subsequent generations. Therefore, the effect of small radiation doses should in no case be underestimated and the mechanisms of the effect of such exposure on living organisms require a more thorough study.

This experiment was carried out in the Department of Radiation Research and Radiation Safety at the Institute of Nuclear Physics SB RAS. “Our main task is to ensure radiation safety during the operation of scientific facilities,” says Mikhail Petrichenkov, Head of the Department. - We are also engaged in the adjustment and calibration of various dosimeters, and for this we need appropriate sources of ionizing radiation. However, these sources can be used for other purposes, for example, for working with biological objects. Irradiation of onion seedlings is not our first experience of such work, we previously conducted a series of similar experiments with cladocera, also together with a scientific team from the Institute of Biophysics SB RAS. Biologists bring us the prepared samples, and we provide the necessary conditions and monitor the course of the experiment. ”

This work was supported by a grant from the Russian Foundation for Basic Research and Krasnoyarsk Regional Science Fund.

Source of information: Press Service of INP SB RAS