Mitotic activity and cell population kinetics in pisum root meristems during and after treatment with high concentrations of tritiated--thymidine
The effects of /sup 3/H-thymidine on cell progression through the mitotic cycle and on cell population kinetics both during and after exposure have been investigated. During exposure there is an accumulation of cells in G2 while the proportions of cells in G1, S and M decrease. Quiescent center cells are induced to synthesize DNA and presumably divide following inhibition of mitosis in the surrounding meristem, accounting in part for a transient increase in mitotic activity. Mitotic activity eventually ceases, however, so metistems are unable to recover from radiation damage during continuous treatment with /sup 3/H-thymidine. Meristems recover from /sup 3/H-thymidine induced reduction in mitotic activity when the roots are no longer exposed to exogenous /sup 3/H-thymidine. Those cells which accumulate in G2 during /sup 3/H-thymidine treatment do not retain the capacity to divide, while cells remaining in G1 and S do divide following treatment and thereby account for recovery. Cytoplasmic irradiation from unincorporated /sup 3/H-thymidine and /sup 14/C-thymidine apparently prevents recovery from inhibition of cell progression through the mitotic cycle which itself is due to nuclear irradiation from incorporated /sup 3/H-thymidine and /sup 14/C-thymidine apparently prevents recovery from inhibition of cell progression through the mitotic cycle which itself is due to nuclear irradiation from incorporated /sup 3/H-thymidine. Unincorporated /sup 3/H-thymidine also prevents recovery from sucrose deprivation in stationary phase G2 cells, indicating that G2 is the most radiosensitive stage in the mitotic cycle under the present conditions and that unincorporated isotopes alone may affect cell progression through the mitotic cycle.
- OSTI ID:
- 7291028
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PISUM
BIOLOGICAL RADIATION EFFECTS
PLANT CELLS
BIOSYNTHESIS
CELL CYCLE
CYTOPLASM
DNA
MERISTEMS
MITOSIS
POPULATION DYNAMICS
ROOTS
THYMIDINE
TRITIUM
AZINES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOMASS
CELL CONSTITUENTS
CELL DIVISION
ENERGY SOURCES
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LEGUMINOSAE
LIGHT NUCLEI
NUCLEI
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLANT TISSUES
PLANTS
PYRIMIDINES
RADIATION EFFECTS
RADIOISOTOPES
RENEWABLE ENERGY SOURCES
RIBOSIDES
SYNTHESIS
YEARS LIVING RADIOISOTOPES
560163* - Radionuclide Effects-Internal Source- Plants- (-1987)