Morphometric Measurements of Scots Pine Needles From Radioactively Contaminated Area

The morphometric indices of needles were investigated in chronically irradiated Scots pine (Pinus sylvestris L.) populations from territories that were heavily contaminated by radionuclides as a result of the Chernobyl Nuclear Power Plant accident. The variability in needle weight and length, as well as the fluctuating asymmetry indices were studied in seven contaminated and two reference populations of Scots pine in 2011, 2013, 2014 and 2016. The weight of needles in the contaminated populations was significantly higher than in the reference population; however, the dependence of this index on the level of radiation exposure was not revealed in the studied range of doses. The length of needles differed significantly from the references populations. The effect changed from decreasing to increasing in various years of observation; however, in 2016 this index decreased with the dose rate of β-radiation. The index of fluctuating asymmetry in needle length was significantly higher than at the reference sites during three years and correlated to the estimated annual absorbed dose in 2011 and 2013. No relationship was revealed between the asymmetry in weight of paired needles and radiation exposure