Scientists studying the ecological legacy of the 1986 nuclear disaster at the Chernobyl nuclear power station have found surprising evidence that some plants can adapt and even flourish in a highly radioactive environment.
An international team of scientists, including researchers from the University of Missouri, grew flax plants in a high radiation environment near the abandoned Chernobyl site and compared the seeds produced to those from plants grown in non-radioactive control plots.
The scientists found that the plants had adapted well to the radiation exposure. In fact, the exposure seemed to have relatively little effect on them, including protein levels that were only about five percent different from control plants, said Ján Miernyk, adjunct professor of biochemistry and research molecular biologist with the U.S. Department of Agriculture’s Agricultural Research Service.
The research results — recently published in the American Chemical Society’s Environmental Science & Technology journal — suggest that plants can adapt their internal chemical processes to shrug off radioactivity.
Martin Hajduch, a plant biotechnology expert with the Slovak Academy of Sciences, primary author of the study and a former member of the MU Interdisciplinary Plant Group, noted that the plants have shown a surprising and unexpected ability over time to adapt to an environment contaminated with radiation – a particularly significant finding given the scope of the disaster in its first few years.
The April 26, 1986, accident at Chernobyl was the world’s worst nuclear disaster. Four hundred times more radioactive material was released than in the atomic bombing of Hiroshima. Fallout was detected over most of Europe.
Among the 134 emergency workers who immediately responded to the explosion and fire, 28 persons died in 1986 due to Acute Radiation Syndrome and 19 more persons died in 1987-2004 from various causes, according to the World Health Organization. The WHO estimated that between 1991 and 1998 that there were 4,995 additional deaths.
After the disaster, four square kilometers of pine forest in the immediate vicinity of the reactor turned reddish-brown and died, earning the name of the “Red Forest.”
Miernyk said that the latest research builds on earlier studies of soybeans grown in the Chernobyl area. These tests showed that the agricultural plants adapted to the contaminated soil through relatively minor changes in their seed composition.
The biggest difference between plants from the radioactive wasteland versus the non-contaminated soil was that levels of hundreds of proteins known to be involved in storage of reduced nitrogen in seeds had been lowered. In some cases, these altered characteristics stayed consistent for at least
three generations of new plants, while other characteristics reverted back to pre-radiation exposure levels.
In the recent test, seeds of a local flax variety, Kyivskyi, were sown in radio-contaminated fields of the Chernobyl region while control plants were planted in non-contaminated soil. The scientists employed two-dimensional electrophoresis and tandem-mass spectrometry to compare seed proteins from the two groups of plants.
Flax responded to the radioactive environment differently than did the soybeans. While soybean plants took up a small amount of radioactivity and distributed it fairly evenly throughout the plant including the seeds, the flax plants seemed to exclude some of the radioactivity from the seeds.
The exact mechanisms for the adaptations are still largely unknown, Miernyk said. Further tests will be needed to identify more information on how the plants adapted and how these biochemical alterations may be used to help areas recover from nuclear disasters.
The plants grown in contaminated soil also functioned similarly to conventionally grown plants, he said, save for relatively minor changes in their protein composition, stress responses and synthetic “machinery.” Miernyk, a co-investigator in the study, said that this research builds on earlier studies of soybeans grown in the Chernobyl area.
— Randy Mertens