Interannual Quality Variability in Motherwort (Leonurus quinquelobatus) Seed Progeny under Chronic Radiation Exposure

Abstract

Abstract—The eight-year dynamics of the quality of motherwort (Leonurus quinquelobatus Gilib.) seed progeny growing for more than 60 years under chronic radiation in the East-Ural Radioactive Trace (EURT) zone, in comparison with background cenopopulations, has been studied. The absorbed dose rates of the parent plants in the EURT area exceed the background level by 1–3 orders of magnitude. The unique dependence between the radiation dose of mother plants and the seed progeny quality was not found. A key role in the formation of Leonurus quinquelobatus seeds belongs to weather factors, as well as the combined effect of weather conditions and chronic irradiation. All the studied characteristics of Leonurus quinquelobatus seed progeny quality from the EURT zone positively correlated with the effective temperature sum in April, i.e., with thermal conditions at the beginning of plant vegetation. The main meteorological factors that affected the physiological response (viability, mutability, and radiosensitivity) of Leonurus quinquelobatus of the background and impact zones were Selyaninov’s index in April of the current season and the amount of precipitation in November of last year. The viability of seed progeny had a negative correlation with Selyaninov’s index, whether the mutability of seed progeny had a positive correlation with Selyaninov’s index for background and impact samples. The physiological response to weather conditions, assessed by the seed radioresistance, was positive in the background samples and negative in the impact samples. The dependencies between the total precipitation in November of last year and the quality of seeds in the background samples were positive, and these dependences were negative in the impact samples.