title: [NOR (nucleolar organizer region) activity in wheat species with different ploidy levels treated with phytohormones].
abstract: The effects of the phytohormones 6-benzylaminopurine (BAP) and 24-epibrassinolide (EB) on the nucleolar sizes in the interphase nuclei of root meristem were studied using the silver-staining procedure in wheat species with different ploidy levels (a polyploid series). In addition, the effects of the phytohormones on the cell mitotic activity in the roots of 5-day-old seedlings were studied. The higher the wheat species ploidy level, the higher its sensitivities to BAP and EB were. In diploid wheat, the maximum increase in the nucleolar organizing region (NOR) activity was observed after treatment with considerably higher phytohormone concentrations compared to tetra- and hexaploid wheat species. The phytohormone treatment increased both the sizes and the number of nucleoli in meristematic cells of seedling roots in all wheat species studied. It was assumed that the differences between the responses of wheat species with three different ploidy levels to different concentrations of phytohormones were related to their effects on the methylation/demethylation of cytosine residues in the rDNA promoter region.
authors.affiliation: Institute of Biochemistry and Genetics, Ufa Scientific Center, Russian Academy of Sciences, Ufa, 450054 Bashkortostan, Russia.
authors.forename: R A
authors.initials: RA
authors.lastname: Fatkhutdinova
authors.forename: F M
authors.initials: FM
authors.lastname: Shakirova
authors.forename: A V
authors.initials: AV
authors.lastname: Chemeris
authors.forename: B E
authors.initials: BE
authors.lastname: Sabirzhanov
authors.forename: V A
authors.initials: VA
authors.lastname: Vakhitov
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001593:Benzyl Compounds; D060406:Brassinosteroids; D002777:Cholestanols / Q000494:pharmacology; D019175:DNA Methylation; D007701:Kinetin; D018519:Meristem / Q000187:drug effects / Q000235:genetics; D009697:Nucleolus Organizer Region / Q000187:drug effects / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics; D011123:Polyploidy; D011687:Purines; D012335:RNA, Ribosomal / Q000187:drug effects; D013260:Steroids, Heterocyclic / Q000494:pharmacology; D014158:Transcription, Genetic; D014908:Triticum / Q000187:drug effects / Q000235:genetics*
chemical_list: D001593:Benzyl Compounds; D060406:Brassinosteroids; D002777:Cholestanols; D010937:Plant Growth Regulators; D011687:Purines; D012335:RNA, Ribosomal; D013260:Steroids, Heterocyclic; D000225:Adenine; C480551:benzylaminopurine; D007701:Kinetin; C023623:brassinolide