Long-term Radiobiological Effects in Pedunculate Oak Trees (Quercus robur L.) Grown from Irradiated Acorns

Currently, research is actively underway to assess the radiation effects of forests, but there are still a number of questions about the ratio of plant reaction to radiation dose (dose–effect). On the territory of Donetsk, research on the effect of gamma rays of ⁶⁰Co on plant organisms was started back in the 70s, and then abandoned. The purpose of this work is to present the ecological and biological features of the functioning of the dendrocerosis, artificially formed 55 years ago from irradiated acorns of the pedunculate oak. The account of the radiation effects of the pedunculate oak was carried out from 2014 to 2024. As a result of the conducted studies, it was found that the viability of radiomorphous oak trees significantly differs from the control sample (p < 0.01). For plants with doses of 26.68 Sv and 44.46 Sv, the median indicator was 3 points. The greatest vulnerability of plants was revealed for doses – 35.57 Sv, 53.32 Sv, and 61.72 Sv – 4–5 points. Morphometric studies have shown that in radiomorphous plants, the trunk diameter at chest height is significantly lower by 27% for group II–V and by 9% for group VI. It was found that the volume of the trunk, the phytomass of the branches, the phytomass of the assimilation apparatus and the phytomass of the root system for group II–V were 48% lower than in the control, and for group VI by 26%. The main types of trunk radiomorphoses were identified in the examined oak trees: zigzagging (group II, III, V, VI – 75 ± 3%; group IV – 60%), multi-stem (II, V, VI – 50 ± 8%; III and IV – 23 ± 5%), trunk slope of more than 30° (II – 43%; III–VI group – 17 ± 3%), as well as combined (on average 27% of the experimental sample). A close correlation (r > 0.95) was noted between the parameters of the mechanical stability of radiomorphic oaks and the d/l ratio. It was found that the average value of relative bending resistance, critical mass and bending stiffness is lower than that of the control sample.

petiolate oak, radiomorphoses, radiation effects, gamma rays Co⁶⁰, viability, allometric dependencies, phytomass, ontogenetic changes, mechanical stability