Effect of gamma irradiation on nucleolar activity in root tip cells of tetraploid Triticum turgidum ssp. durum L.

Autor: von Well E; ARC-Small Grain, Field Crops, Division, Private Bag X29, Bethlehem, 9700, South Africa. vonwelle@arc.agric.za., Booyse M; ARC-Biometry, Private Bag X5013, Stellenbosch, 7599, South Africa., Fossey A; Central University of Technology, 1 Park Street, Bloemfontein, 9301, South Africa.
Jazyk: angličtina
Zdroj: Protoplasma [Protoplasma] 2022 Mar; Vol. 259 (2), pp. 453-468. Date of Electronic Publication: 2021 Jun 30.
DOI: 10.1007/s00709-021-01684-4
Abstrakt: Ionizing irradiation induces positive or negative changes in plant growth (M1) depending on the amount of irradiation applied to seeds or plant parts. The effect of 50-350 Gy gamma irradiation of kernels on nucleolar activity, as an indicator of metabolic activity, in root tip cells of tetraploid wheat Triticum turgidum ssp. durum L. cv. Orania (AABB) was investigated. The number of nucleoli present in nuclei and micronuclei as well as the mitotic index in the different irradiation dosages was used as an indicator of the cells entering mitosis, the chromosomes with nucleolar organizer regions that are active as well as chromosome doubling in the event of unsuccessful mitotic division. Nucleolar activity was investigated from 17.5 to 47.5 h after the onset of imbibition to study the first mitotic division and its consequences on the cells that were in G 2 and G 1 phases at the time of gamma irradiation. Untreated material produced a maximum of four nucleoli formed by the nucleolar organizing regions (NORs) on chromosomes 1B and 6B. In irradiated material, additional nucleoli were noted that are due to the activation of the NORs on chromosome 1A in micronuclei. The onset of mitosis was highly significantly retarded in comparison to the control due to checkpoints in the G 2 phase for the repairing of damaged DNA. This study is the first to report on the appearance of nucleoli in micronuclei as well as activation of NORs in the micronuclei that are inactive in the nucleus and the effect of chromosome doubling on nucleolar activity in the event of unsuccessful mitotic division.
(© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)
Databáze: MEDLINE
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