The Effect of Ionizing Radiations on the Broad Bean Root Part VIII

Lh, Gray; Me, Scholes

doi:10.1259/0007-1285-24-278-82

Cited by 122 publications

(10 citation statements)

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“…This phenomenon has already been described, namely by GRAY (1951) in Vicia faba and by LEVAN (1939) in Allium cepa. In Scilla obtusifolia also chromosomal aberrations in the cells of the tips were observed (MARTINOLI 1953(MARTINOLI , 1954.…”

Section: ]supporting

confidence: 57%

A Summary of the Effects of Ionizing andUVRadiations on Root-Tips ofScilla ObtusifoliaPoir

Martinoli

1961

Caryologia

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Section: ]supporting

confidence: 57%

A Summary of the Effects of Ionizing andUVRadiations on Root-Tips ofScilla ObtusifoliaPoir

Martinoli

1961

Caryologia

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“…Gray and Scholes (19) report that during a 20 hour period an elongating cell in a V. fab~ root increases its length tenfold while a complete mitotic cycle, during which a meristematic cell would in effect only double its size, takes about 24 hours. An analysis of control roots from several of the experiments reported here showed no correlation between variations in length increase and mitotic frequency.…”

Section: Methodsmentioning

confidence: 99%

“…The mefistem was assumed to be 2 ram. long (19) and thus the 0 hour determination included only the first 1 ram. of the elongation zone in which the cells are small and give a low index of cell elongation.…”

Section: Ceil Elongation and Mitotic Frequency Studiesmentioning

confidence: 99%

Cytological Studies on the Antimetabolite Action of 2,6-Diaminopurine in Vicia Faba Roots

Setterfield

Duncan

1955

The Journal of Cell Biology

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At a concentration of 9.6 x 10–5 M, 2,6-diaminopurine (DAP) completely inhibited cell enlargement, cell division, and DNA synthesis (determined by microphotometric measurement of Feulgen dye) in Vicia faba roots. Inhibition of cell enlargement was partially reversed by adenine, guanine, xanthine, adenosine, and desoxyadenosine. Guanine and the nucleosides gave the greatest reversal, suggesting that one point of DAP action upon cell enlargement is a disruption of nucleoside or nucleotide metabolism, possibly during pentosenucleic acid synthesis. DAP inhibited cell division by preventing onset of prophase. At the concentrations used it had no significant effect on the rate or appearance of mitoses in progress. Inhibition of entrance into prophase was not directly due to inhibition of DNA synthesis since approximately half of the inhibited nuclei had the doubled (4C) amount of DNA. Adenine competitively reversed DAP inhibition of cell division, giving an inhibition index of about 0.5. Guanine gave a slight reversal while xanthine, hypoxanthine, adenosine, and desoxyadenosine were inactive. A basic need for free adenine for the onset of mitosis was suggested by this reversal pattern. Meristems treated with DAP contained almost no nuclei with intermediate amounts of DNA, indicating that DAP prevented the onset of DNA synthesis while allowing that underway to reach completion. The inhibition of DNA synthesis was reversed by adenine, adenosine, and desoxyadenosine although synthesis appeared to proceed at a slower rate in reversals than in controls. Inhibition of DNA synthesis by DAP is probably through nucleoside or nucleotide metabolism. A small general depression of DNA content of nuclei in the reversal treatments was observed. This deviation from DNA "constancy" cannot be adequately explained at present although it may be a result of direct incorporation of DAP into DNA. The possible purine precursor, 4-amino-5-imidazolecarboxamide gave no reversal of DAP inhibition of cell elongation and cell division and only a slight possible reversal of inhibition of DNA synthesis.

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“…It is furthermore clear that the reduction in number of laterals appearing in subsequently formed tissue after exposure of the 1 to 4 cm region to 300 or 500 rad was due to scattered radiation received by the final 1 mm of root tissue, and was not an abscopal effect. The possibility that the growth of the main root might have been affected by irradiation of the proximal part deserves special attention because Gray and Scholes (1951) reported a slight increase in growth-rate of roots irradiated with 143 r x-rays while the tips were shielded. Read (1959), on the other hand, observed no change in growth after irradiation of the whole root except for 5 mm at the tip, and the insensitivity of the root to reduction of growth when a small segment of elongating or young differentiated tissue was exposed was demonstrated by Gray and Boag (1965) who observed essentially no effect of exposing the region 6 to 11 mm from the tip to 20 000 rad, or the region 2 to 2-5 cm to 100 000 rad, of 15 Mev electrons.…”

Section: Abscopal Effectsmentioning

confidence: 99%

Effect of X-rays on the Number and Growth-rate of Lateral Roots inVicia Faba

Howard¹

1966

International Journal of Radiation Biology and Related Studies

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The Effect of Ionizing Radiations on the Broad Bean Root Part VIII

Cited by 122 publications

References 0 publications

A Summary of the Effects of Ionizing andUVRadiations on Root-Tips ofScilla ObtusifoliaPoir

A Summary of the Effects of Ionizing andUVRadiations on Root-Tips ofScilla ObtusifoliaPoir

Cytological Studies on the Antimetabolite Action of 2,6-Diaminopurine in Vicia Faba Roots

Effect of X-rays on the Number and Growth-rate of Lateral Roots inVicia Faba

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