Abstract
Part of the changes in the hormonal balance involved in plant senescence is due to an auxin limitation. Some of its physiological consequences are studied using pear (Pyrus communis L.) cells cultured in a continuously renewed medium in which 2,4-dichlorophenoxyacetic acid (2,4-D) was absent. In these conditions, an assessment was made of the absence of nutrient deficiency.
In the period preceding cell death, the rate of respiration and ethylene production remain low, and no major changes were observed in the total protein and RNA content of the cells. Beginning around day 9, an important efflux of three amino acids (serine, threonine, and aspartic acid) occurs among which serine represents more than 52%. However, exogenous serine supplied to the medium fails to show any senescence promoting effect. At the same time, leucine uptake and incorporation sharply and simultaneously increased. The presence of 2,4-D inhibits both these phenomena and prevents cell death. It is proposed that auxin deprivation is responsible for unmasking a program of synthesis of new proteins involved in cell death.
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.
- Allen R. J. The estimation of phosphorus. Biochem J. 1940 Jun;34(6):858–865. doi: 10.1042/bj0340858. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Arnold W. N. Beta-fructofuranosidase from grape berries. Biochim Biophys Acta. 1965 Oct 25;110(1):134–147. doi: 10.1016/s0926-6593(65)80102-3. [DOI] [PubMed] [Google Scholar]
- De Leo P., Sacher J. A. Control of ribonuclease and acid phosphatase by auxin and abscisic acid during senescence of Rhoeo leaf sections. Plant Physiol. 1970 Dec;46(6):806–811. doi: 10.1104/pp.46.6.806. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Francki R. I., Zaitlin M., Jensen R. G. Metabolism of Separated Leaf Cells: II. Uptake and Incorporation of Protein and Ribonucleic Acid Precursors by Tobacco Cells. Plant Physiol. 1971 Jul;48(1):14–18. doi: 10.1104/pp.48.1.14. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Frenkel C., Haard N. F. Initiation of Ripening in Bartlett Pear with an Antiauxin alpha(p-Chlorophenoxy)isobutyric Acid. Plant Physiol. 1973 Oct;52(4):380–384. doi: 10.1104/pp.52.4.380. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martin C., Thimann K. V. Role of Protein Synthesis in the Senescence of Leaves: II. The Influence of Amino Acids on Senescence. Plant Physiol. 1972 Oct;50(4):432–437. doi: 10.1104/pp.50.4.432. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pech J. C., Romani R. J. Senescence of Pear Fruit Cells Cultured in a Continuously Renewed, Auxin-deprived Medium. Plant Physiol. 1979 Nov;64(5):814–817. doi: 10.1104/pp.64.5.814. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Romani R. J., Bos T. J., Pech J. C. Cycloheximide stimulation of cyanide-resistant respiration in suspension cultures of senescent pear fruit cells. Plant Physiol. 1981 Oct;68(4):823–826. doi: 10.1104/pp.68.4.823. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shibaoka H., Thimann K. V. Antagonisms between Kinetin and Amino Acids: Experiments on the Mode of Action of Cytokinins. Plant Physiol. 1970 Aug;46(2):212–220. doi: 10.1104/pp.46.2.212. [DOI] [PMC free article] [PubMed] [Google Scholar]