THE GENETICS AND FINE-STRUCTURE OF VARIEG ATED FORMS INDUCED BY N-NITROSO-N-METHYLUREA IN MUSTARD

A genetic analysis of variegated plants induced by N-nitroso-N-methylu rea in mustard (cv. Donskaya-5) was performed; Based on non-Mendelian segregation in progeny and uniparental maternal inheritance of the mut ant trait, an extranuclear nature of variegation is established. Elect ron microscopy of plastids in mutant tissues revealed profound alterat ions in their fine structure: the number of lamellae in grana decrease d, while grana became more abundant in yellow-green areas of the leaf; a complete or partial absence of the lamellae system in yellow and wh ite areas is observed. The extranuclear mode of inheritance of the chl orophyll anomaly together with the affected plastid structure strongly evidence plastom-mediated induced variegation in mustard.