DNA Integrity and Synthesis in Relation to Seed Vigour in Sugar Beet

Abstract

DNA repair, including the ligation of DNA breaks, is one of the earliest events during rehydration from the dry state in seeds. The gamma-irradiation of dry embryos produces DNA damage detectable on alkaline gels. Repair has been shown to occur in sugar-beet embryos following a two-hour period of imbibition. The effect of vigour on DNA repair following irradiation was investigated using two sugarbeet growers lots. Improvements in seed vigour following the primed advancement treatment have been demonstrated through accelerated seedling emergence in the held. Earlier studies have shown that the advanced seed had a higher ratio of extractable high molecular weight RNA to high molecular weight DNA than untreated seed. Using Feulgen staining and image analysis, the proportions of 2C and 4C nuclei were calculated. Nuclei from the advanced seed showed a higher proportion of 2C-4C intermediates, 4C and 8C DNA contents than untreated seed indicating that the advancing treatment had progressed the onset of DNA replicative synthesis.