Abstract
After gamma irradiation of wheat grain, embryos can germinate and grow without detectable mitotic figures and without increases in tissue‐cell numbers. Roots growing without DNA synthesis after irradiation show the 2 striking examples of normal nuclear behavior on the anatomic level that occur in unirradiated roots: (1) trichoblast nuclei migrate into the root hairs and change shape; and (2) nuclei in sieve‐tube elements and vessel elements disappear. Nuclei that do not synthesize DNA do synthesize RNA, some of which moves into the cytoplasm. Therefore, the irradiation that prevents DNA synthesis and mitosis has not completely inactivated all nuclear functions. On a purely descriptive level, the irradiation that prevents cell division seems to prevent the initiation at the apical “meristem” of immature vascular elements but does not prevent maturation in those vascular elements detectable before irradiation. Although the ultimate extent of growth is reduced in those structures which suffer radiation‐induced mitotic inhibition, it is not reduced in those structures (epiblast, coleorhiza, root hairs) which develop without cell division in unirradiated controls and, therefore, have no mitosis for the radiation to inhibit. This established generalization leads to the inference that the smaller sizes attained by gamma‐plantlet roots and leaves may be attributed largely or almost entirely to the radiation‐induced mitotic inhibition rather than to other actions of radiation. Irrespective of the validity of this last inference, the extent of growth theoretically possible without cell division is at least as great as the observed growth of gamma‐plantlets under given experimental conditions. Also reported are variations in radiation sensitivity among different batches of grain, among different organs within the same embryo, and among different cell types within the same organ. These variations are discussed with reference to suggestions and precautions concerning the use of radiation‐induced mitotic inhibition for developmental studies.
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Claims 10
Claim · model-written summary
Irradiated wheat embryos germinated and grew without detectable mitoses or increased tissue-cell numbers.
- Taxon
- wheat
Triticum aestivume0 - Organ / stage
- embryose0
- Treatment
- gamma irradiatione0
- Outcome
- germinate and grow without detectable mitotic figures and without increases in tissue‐cell numberse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After gamma irradiation of wheat grain, embryos can germinate and grow without detectable mitotic figures and without increases in tissue‐cell numbers.”
Claim · model-written summary
Trichoblast nuclei migrated into root hairs and changed shape despite absent DNA synthesis after irradiation.
- Taxon
- WHEATTriticum aestivumt0
- Organ / stage
- root hairse0
- Outcome
- trichoblast nuclei migrate into the root hairs and change shapee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Roots growing without DNA synthesis after irradiation show the 2 striking examples of normal nuclear behavior on the anatomic level that occur in unirradiated roots: (1) trichoblast nuclei migrate into the root hairs and change shape”
t0“WHEAT”
Claim · model-written summary
Nuclei in sieve-tube and vessel elements disappeared despite absent DNA synthesis after irradiation.
- Taxon
- WHEATTriticum aestivumt0
- Organ / stage
- sieve‐tube elements and vessel elementse0
- Outcome
- nuclei in sieve‐tube elements and vessel elements disappeare0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nuclei in sieve‐tube elements and vessel elements disappear”
t0“WHEAT”
Claim · model-written summary
Nuclei lacking DNA synthesis still synthesized RNA, some of which entered the cytoplasm.
- Taxon
- WHEATTriticum aestivumt0
- Outcome
- synthesize RNA, some of which moves into the cytoplasme0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nuclei that do not synthesize DNA do synthesize RNA, some of which moves into the cytoplasm.”
t0“WHEAT”
Claim · model-written summary
Irradiation preventing cell division appeared to prevent initiation of immature vascular elements at the apical meristem.
- Taxon
- WHEATTriticum aestivumt0
- Treatment
- irradiatione0
- Outcome
- initiation at the apical “meristem” of immature vascular elementse0
- Direction
- prevente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“irradiation that prevents cell division seems to prevent the initiation at the apical “meristem” of immature vascular elements”
t0“WHEAT”
Claim · model-written summary
Irradiation did not prevent maturation of vascular elements detectable before treatment.
- Taxon
- WHEATTriticum aestivumt0
- Treatment
- irradiatione0
- Outcome
- maturation in those vascular elementse0
- Direction
- does not prevente0
- Qualifier
- detectable before irradiatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“does not prevent maturation in those vascular elements detectable before irradiation”
t0“WHEAT”
Claim · model-written summary
Growth extent fell in structures with radiation-induced mitotic inhibition.
- Taxon
- WHEATTriticum aestivumt0
- Treatment
- radiation‐induced mitotic inhibitione0
- Outcome
- ultimate extent of growthe0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the ultimate extent of growth is reduced in those structures which suffer radiation‐induced mitotic inhibition”
t0“WHEAT”
Claim · model-written summary
Growth extent did not fall in epiblast, coleorhiza, and root hairs that develop without cell division in controls.
- Taxon
- WHEATTriticum aestivumt0
- Organ / stage
- epiblast, coleorhiza, root hairse0
- Outcome
- extent of growthe1
- Direction
- not reducede0
- Comparator
- unirradiated controlse0
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it is not reduced in those structures (epiblast, coleorhiza, root hairs) which develop without cell division in unirradiated controls”
e1“the ultimate extent of growth is reduced in those structures which suffer radiation‐induced mitotic inhibition”
t0“WHEAT”
Claim · model-written summary
The smaller roots and leaves of gamma plantlets were inferred to be largely due to mitotic inhibition.
- Taxon
- WHEATTriticum aestivumt0
- Outcome
- smaller sizes attained by gamma‐plantlet roots and leavese0
- Qualifier
- radiation‐induced mitotic inhibitione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“smaller sizes attained by gamma‐plantlet roots and leaves may be attributed largely or almost entirely to the radiation‐induced mitotic inhibition”
t0“WHEAT”
Claim · model-written summary
Radiation sensitivity varied across grain batches, organs, and cell types.
- Taxon
- WHEATTriticum aestivumt0
- Outcome
- variations in radiation sensitivitye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“variations in radiation sensitivity among different batches of grain, among different organs within the same embryo, and among different cell types within the same organ”
t0“WHEAT”
The same questions in other papers
radiation · growth · Triticum aestivum (wheat)Positive and negative results
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- no effect
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- positive
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See all 89 papers →radiation · phenology · Triticum aestivum (wheat)Results agree
1 paper in the same direction as this paper
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.