White clover from the exclusion zone of the Chernobyl NPP: Morphological, biochemical, and genetic characteristics.

A comprehensive study of the biological effects of chronic radiation exposure (8 µGy/h) in populations of white clover (Trifolium repens L.) from the Chernobyl exclusion zone was carried out. White clover is one of the most important pasture legumes, having many agricultural applications. Studies at two reference and three radioactively contaminated plots showed no stable morphological effects in white clover at this level of radiation exposure. Increased activities of catalase and peroxidases were found in some impacted plots. Auxin concentration was enhanced in the radioactively contaminated plots. Genes involved in the maintenance of water homeostasis and photosynthetic processes (TIP1 and CAB1) were upregulated at radioactively contaminated plots.

Radiation exposure in the remote period after the Chernobyl accident caused oxidative stress and genetic effects in Scots pine populations.

Even 30 years after the Chernobyl accident, biological effects of irradiation are observed in the chronically exposed Scots pine populations. Chronic radiation exposure at dose rates above 50 mGy∙yr-1 caused oxidative stress and led to the increase of antioxidants concentrations in these populations. Genetic variability was examined for 6 enzymes and 14 enzymatic loci of 6 Scots pine populations. Dose rates over 10 mGy∙yr-1 caused the increased frequency of mutations and changes in genetic structure of Scots pine populations. However, the same dose rates had no effect on enzymatic activities. The results indicate that even relatively low dose rates of radiation can be considered as an ecological factor which should be taken into account for ecological management and radiation protection of biota species.