Seed Germination Kinetics as an Informative Tool for Assessing the Impact of Ionizing Radiation (on the Example of <i>Arabidopsis Thaliana</i> Aba-mutant Lines)

Abstract

We have analyzed the kinetics of seed germination of the model plant Arabidopsis thaliana after γ-irradiation at doses of 50, 100 and 150 Gy. The following lines were selected as study objects: abi3-8 with a mutation in the ABI3 gene and with reduced sensitivity to the natural form of abscisic acid and aba3-1 genotype with a mutation in the ABA3 gene and a reduced level of endogenous abscisic acid. Wild type Col-8 was used as a control. To study the effect of γ-radiation on various aspects of seed germination (germinability, germination time and rate, synchrony of germination, etc.), the germination kinetics was assessed using the Germinationmetrics package for the R programming environment. Control and irradiated seeds (radiation source – 60Co) were grown on half-strength Murashige-Skoog medium under controlled conditions. Germination was assessed during the first six days after transfer to the phytotron by the rupture of the endosperm and the appearance of a root. In total, three independent experiments were carried out with three biological replications in each. A more pronounced effect of γ-radiation at a dose of 150 Gy on all studied genotypes was noted. Germination clustering showed that the distribution of the percentage of seed germination by day depends more on the genotype than on the dose of exposure. The best indicators of germination, speed and time interval between germination of 10% to 90% of seeds were noted for non-irradiated seeds of the abi3-8 line. The results obtained and a comparative analysis with previously published data suggest that the assessment of germination kinetics using the Germinationmetrics package for R is a clear and quite informative tool for studying the effect of ionizing radiation and other abiotic factors on various aspects of seed germination.