Stage sensitivity and dose response of meiotic chromosomes of pollen mother cells of Tradescantia to X-rays

Ma, Te­-Hsiu; Kontos, George J.; Anderson, Van A.

doi:10.1016/0098-8472(80)90010-6

Cited by 27 publications

(12 citation statements)

References 13 publications

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“…It was possible, on the other hand, to determine the dose-response curve with a slope of 1.330 on a log-log graph for X ray-induced micronuclei in pollen tetrads at earlier stage as shown in Figure 4. This slope value is larger than 1.171 for X ray-induced micronuclei in pollen tetrads at earlier stage calculated by us based on the data published by Ma et al (1980). The present value is rather closer to 1.249 obtained for X ray-induced dicentric bridges (Fig.…”

Section: Discussionmentioning

confidence: 45%

Dicentric chromosome bridges in root tips and micronuclei in pollen tetrads induced by X rays and maleic hydrazide in Tradescantia clone BNL 4430.

Xiao

Ichikawa

1997

Genes Genet. Syst.

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Inductions of dicentric chromosome bridges in root-tip cells and of micronuclei in pollen tetrads by X rays and maleic hydrazide (MH) were studied in Tradescantia clone BNL 4430, in order to compare the accuracies of these endpoints for mutagenicity testings with that of somatic pink mutations in the stamen hairs of the same clone, the most accurate endpoint established in higher plant testers. The frequency of dicentric bridges in root-tip cells increased with X-ray doses with a slope of 1.249 on a log-log graph, the slope value being unexpectedly small (much smaller than the theoretical value of 2 for two-break events). The dose-response curve on a log-log graph for MH-induced dicentric bridges had a somewhat smaller slope of 1.188, and the bridges observed were predominantly of chromatid type, reflecting the nature of MH acting at the S period of cell cycle. As for X-ray-and MH-induced micronuclei in pollen tetrads, on the other hand, the dose-response curves could not be determined, excepting that for X-ray-induced micronuclei in pollen tetrads at earlier stage. Namely, the data obtained from pollen tetrads at later stage were not consistent with X-ray and MH doses, and those from pollen tetrads at earlier stage were also inconsistent with MH doses. These results were contrary to our expectation that the frequency of micronuclei would be more reliable in pollen tetrads at later stage than in those at earlier stage at least in clone BNL 4430, a hybrid clone. The micronucleus assay in pollen tetrads was also found to be unsuited for determining the effects of MH. Therefore, the assay of somatic mutations in Tradescantia stamen hairs is concluded to be the most accurate and most reliable mutagenicity test system with a high degree of reappearance.

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Section: Discussionmentioning

confidence: 45%

Dicentric chromosome bridges in root tips and micronuclei in pollen tetrads induced by X rays and maleic hydrazide in Tradescantia clone BNL 4430.

Xiao

Ichikawa

1997

Genes Genet. Syst.

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“…The Trudescuntiu-Micronucleus (Trad-MCN) bioassay, also referred to as the "MCN-in-Tetrad" test system, has been developed and described by Ma [Ma et al, 1978;Ma, 1979, 19811 who has shown the sensitivity and utility of the assay for the detection of clastogenic chemical and physical agents [Ma, 1979;Ma et al, 1980Ma et al, , 1981Ma et al, , 1982a. The Trad-MCN assay draws its overall sensitivity from the high sensitivity of early meiotic prophase 1 chromosomes, the high degree of synchrony of these chromosomes (from which micronuclei (MCN) are derived) in cells from a given bud, and the synchronous progression of cells through the meiotic process to the early tetrad stage where MCN are easily scored.…”

Section: Introductionmentioning

confidence: 99%

Influence of strong magnetic fields on genetic endpoints in Tradescantia tetrads and stamen hairs

Baum

Nauman

1984

Environ. mutagen

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Inflorescences from Tradescantia clones 4430 and 02 were subjected to mean magnetic field intensities of 0.16 or 0.76 to 0.78 tesla for 6 to 11 days. Following exposures to both intensities, damage to pollen mother cell chromosomes at early prophase was determined by scoring the frequency of micronuclei in early tetrads. Pink mutations in stamen hair cells of clone 4430 were scored for 15 days after a 6-day exposure to the higher intensity level while clone 02 was scored during and for 6 days after an 11-day exposure to the 0.16 tesla field. Comparison of micronuclei results from exposed groups to those for control groups that were scored concurrently showed that there was no significant difference in frequency for either clone or either field intensity (P values in contingency table analyses were between 0.42 and 0.6); similarly, pink mutation frequencies for clone 4430 exposed and control groups did not differ significantly (a contingency test yielded X2 = 1.4 and P = 0.26). Comparisons of pink mutation frequencies during the first 6 days of clone 02 exposure to those in the period when an effect should be greatest (days 7 through 17 revealed no significant difference (X2 = 2.6 and P = 0.1) between the two scoring periods, through frequencies were higher during the early scoring period.

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“…The selection of proper buds is done on the basis of size and relative position among the series of buds in a given inflorescence. A (17), cyclohexylamine, maleic hydrazide (20), X-rays (14,17) and ultraviolet light (20). Fourteen other chemicals in the forms of gas and liquid were tested and reported at the 11th Annual Meeting of the Environmental Mutagen Society (21).…”

Section: Tradescantia Micronucleus Bioassaymentioning

confidence: 99%

“…This 1,2-dibromoethane (16) and followed by x-rays and known mutagens (17). The dose-response curves were established by 1,2-dibromoethane and x-ray treatment (14). The linear regression dose-response curve of x-rays is shown in Figure 3.…”

Section: Introductionmentioning

confidence: 99%

“…When mature pollen grains were cultured on a simple lactose-agar medium, radiation (5,7,8,10) or chemical mutagen (7,9,12,13) Meiotic chromosomes of pollen mother cells (PMC) have long been known to be more sensitive than mitotic chromosomes to radiation (3,4,6,14) but they were rarely used for studies on the induced chromosome aberrations because the aberrations were hard to be analyzed and scored to compile quantitative data. The major problem was due to the looseness of the metaphase I chromosomes and their unclear image in the meiotic PMC preparations.…”

Section: Introductionmentioning

confidence: 99%

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Stage sensitivity and dose response of meiotic chromosomes of pollen mother cells of Tradescantia to X-rays

Cited by 27 publications

References 13 publications

Dicentric chromosome bridges in root tips and micronuclei in pollen tetrads induced by X rays and maleic hydrazide in Tradescantia clone BNL 4430.

Dicentric chromosome bridges in root tips and micronuclei in pollen tetrads induced by X rays and maleic hydrazide in Tradescantia clone BNL 4430.

Influence of strong magnetic fields on genetic endpoints in Tradescantia tetrads and stamen hairs

Tradescantia Micronucleus Bioassay and Pollen Tube Chromatid Aberration Test for in Situ Monitoring and Mutagen Screening

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