Abstract
Spinach seeds (Spinacia oleracea L.) given massive doses of γ-irradiation (500 krad) germinate and form a seedling with two green cotyledons and a radicle, but develop no further. Irradiated cotyledons show no increase in cell number or total DNA over a 7-day period in the light, while in control cotyledons there is a small increase in cell number and large increases in total DNA and chloroplast number. The chloroplasts of irradiated cotyledons are delayed in their division, become greatly enlarged and contain large amounts of starch. The whole population of chloroplasts subsequently undergoes a wave of division. The daughter chloroplasts show normal thylakoid development, but have some abnormal structural features caused by the radiation stress. Information on the effect of X-irradiation, ultraviolet irradiation, and 5-fluorodeoxyuridine on chloroplast replication and on chloroplast and nuclear DNA synthesis was obtained from cultured spinach leaf discs. It appears that chloroplast replication is more resistant to ionizing radiation than cell division and can proceed in the absence of nuclear DNA synthesis and greatly reduced chloroplast DNA synthesis.
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- BURTON K. A study of the conditions and mechanism of the diphenylamine reaction for the colorimetric estimation of deoxyribonucleic acid. Biochem J. 1956 Feb;62(2):315–323. doi: 10.1042/bj0620315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boasson R., Bonner J. J., Laetsch W. M. Induction and regulation of chloroplast replication in mature tobacco leaf tissue. Plant Physiol. 1972 Jan;49(1):97–101. doi: 10.1104/pp.49.1.97. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boasson R., Laetsch W. M. Chloroplast replication and growth in tobacco. Science. 1969 Nov 7;166(3906):749–751. doi: 10.1126/science.166.3906.749. [DOI] [PubMed] [Google Scholar]
- Bogorad L., Mets L. J., Mullinix K. P., Smith H. J., Strain G. C. Possibilities for intracellular integration: The ribonucleic acid polymerases of chloroplasts and nuclei, and genes specifying chloroplast ribosomal proteins. Biochem Soc Symp. 1973;(38):17–41. [PubMed] [Google Scholar]
- Grimes G. W., Mahler H. R., Perlman R. S. Nuclear gene dosage effects on mitochondrial mass and DNA. J Cell Biol. 1974 Jun;61(3):565–574. doi: 10.1083/jcb.61.3.565. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kadouri A., Atsmon D., Edelman M. Satellite-rich DNA in cucumber: hormonal enhancement of synthesis and subcellular identification. Proc Natl Acad Sci U S A. 1975 Jun;72(6):2260–2264. doi: 10.1073/pnas.72.6.2260. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lyman H., Jupp A. S., Larrinua I. Action of Nalidixic Acid on Chloroplast Replication in Euglena gracilis. Plant Physiol. 1975 Feb;55(2):390–392. doi: 10.1104/pp.55.2.390. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Painter R. B. DNA damage and repair in eukaryotic cells. Genetics. 1974 Sep;78(1):139–148. doi: 10.1093/genetics/78.1.139. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Possingham J. V. Chloroplast growth and division during the greening of spinach leaf discs. Nat New Biol. 1973 Sep 19;245(142):93–94. doi: 10.1038/newbio245093a0. [DOI] [PubMed] [Google Scholar]
- Rose R. J., Cran D. G., Possingham J. V. Changes in DNA synthesis during cell growth and chloroplast replication in greening spinach leaf disks. J Cell Sci. 1975 Jan;17(1):27–41. doi: 10.1242/jcs.17.1.27. [DOI] [PubMed] [Google Scholar]
- Rose R. J., Cran D. G., Possingham J. V. Distribution of DNA in dividing spinach chloroplasts. Nature. 1974 Oct 18;251(5476):641–642. doi: 10.1038/251641a0. [DOI] [PubMed] [Google Scholar]
- Verma D. P., Van Huystee R. B. Induction of giant cells in suspension cultures of Arachis hypogaea, L. by massive irradiation. Radiat Res. 1971 Dec;48(3):518–530. [PubMed] [Google Scholar]