Chromosomal aberrations and delays in cell progression induced by x-rays in Tradescantia clone 02 meristems
In root meristems of Tradescantia clone 02 (developed by Sparrow and his colleagues for mutation studies), X-rays interfere with the progression of cells through the cell cycle and induce chromosomal aberrations in a dose-dependent manner consistent with linear-quadratic kinetics. Sequential mitotic cell accumulations after irradiation indicate that sensitivity to aberrration induction is probably greatest in cells from late S to early G2, with chromatid interchanges the most frequent aberration type and all aberrations consistent with intiation from the interaction between two lesions. The ratio of the coefficients in the linear (..cap alpha..) and the quadratic (..beta..) terms (..cap alpha../..beta..) is equal to the dose average of specific energy produced by individual particles in the site where interaction takes place. The ratio ..cap alpha../..beta.. for chromosomal aberrations is similar to that previously found for X-ray-induced mutation in Tradescantia stamen hairs, supporting the proposal that radiation-induced mutational events are due to chromosomal aberrations with interaction distances of about 1 ..mu..m. Abrahmson and co-workers have noted that both ..cap alpha../..beta.. ratios appear to be related to nuclear target size and are similar for chromosomal and mutational endpoints in the same organism. These findings support this concept; however, it is apparent that any situation which diminishes yield at high doses (e.g., mitotic delay) will primarily affect the ..beta.. component, resulting in low assessments of interaction site diameters.
- Research Organization:
- Columbia Univ., NY
- OSTI ID:
- 5272283
- Journal Information:
- Environ. Manage.; (United States), Vol. 5:3
- Country of Publication:
- United States
- Language:
- English
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RADIATION-INDUCED CHROMOSOME ABERRATIONS AND LOSS OF REPRODUCTIVE INTEGRITY IN TRADESCANTIA
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Related Subjects
CHROMOSOMAL ABERRATIONS
RADIOINDUCTION
MERISTEMS
BIOLOGICAL RADIATION EFFECTS
MITOTIC DELAY
CELL CYCLE
DOSE-RESPONSE RELATIONSHIPS
MITOTIC INDEX
TRADESCANTIA
X RADIATION
BIOLOGICAL EFFECTS
BODY
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
MUTATIONS
PLANT TISSUES
PLANTS
RADIATION EFFECTS
RADIATIONS
TISSUES
560141* - Radiation Effects on Plants- Basic Studies- (-1987)