Abstract
The interaction between kinetin and naphthaleneacetic acid in the regulation of senescence of excised tissue of mature broccoli leaves has been used to examine the extent of synchrony between changes in chlorophyll, RNA, and protein. Kinetin increased the net uptake of 14C-labeled orotic acid and leucine. Naphthaleneacetic acid decreased the effect of kinetin on net uptake after long treatment, but in short-time treatments the auxin increased the effect of kinetin on net uptake. Results of long (24 hr) treatments indicated a general synchrony between the loss of RNA, protein, and chlorophyll. Naphthaleneacetic acid reduced the stabilizing effect of kinetin upon chlorophyll content and upon the content and synthesis of RNA. In short-time experiments, however, RNA content and synthesis were transiently increased by kinetin, and further increased by kinetin plus naphthaleneacetic acid, while chlorophyll content decreased in the presence of kinetin and decreased further in the presence of kinetin plus naphthaleneacetic acid. Actinomycin-D accelerated the loss of chlorophyll, RNA and protein and strongly depressed the rate of RNA synthesis. In the presence of actinomycin-D the stabilizing effect of kinetin upon RNA was substantially reduced. In contrast, the chlorophyll and protein contents remained higher than in the control. Actinomycin-D did not nullify the basal incorporation of orotic acid into RNA, nor did it negate the effect of kinetin upon incorporation. The failure of synchrony between changes in chlorophyll and RNA does not substantiate the proposal that kinetin regulates senescence by a direct effect upon DNA-dependent RNA synthesis.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Anderson J. W., Rowan K. S. Activity of aminoacyl-transfer-ribonucleic acid synthetases in tobacco-leaf tissue in relation to senescence and to the action of 6-furfurylaminopurine. Biochem J. 1966 Oct;101(1):15–18. doi: 10.1042/bj1010015. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Beevers L. Effect of Gibberellic Acid on the Senescence of Leaf Discs of Nasturtium (Tropaeolum majus). Plant Physiol. 1966 Jun;41(6):1074–1076. doi: 10.1104/pp.41.6.1074. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Biswas S., Biswas B. B. Effect of polyribonucleotides on amino acid incorporation by chloroplast ribosomes. Experientia. 1965 May 15;21(5):251–253. doi: 10.1007/BF02297007. [DOI] [PubMed] [Google Scholar]
- Key J. L., Shannon J. C. Enhancement by Auxin of Ribonucleic Acid Synthesis in Excised Soybean Hypocotyl Tissue. Plant Physiol. 1964 May;39(3):360–364. doi: 10.1104/pp.39.3.360. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Osborne D. J. Effect of Kinetin on Protein & Nucleic Acid Metabolism in Xanthium Leaves During Senescence. Plant Physiol. 1962 Sep;37(5):595–602. doi: 10.1104/pp.37.5.595. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Srivastava B. I., Ware G. The effect of kinetin on nucleic acids and nucleases of excised barley leaves. Plant Physiol. 1965 Jan;40(1):62–64. doi: 10.1104/pp.40.1.62. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Von Abrams G. J., Pratt H. K. Interaction of naphthaleneacetic Acid and kinetin in the senescence of detached leaves. Plant Physiol. 1966 Nov;41(9):1525–1530. doi: 10.1104/pp.41.9.1525. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Woolhouse H. W. The nature of senescence in plants. Symp Soc Exp Biol. 1967;21:179–213. [PubMed] [Google Scholar]