Summary
After a 6 day incubation period, abscisic acid (ABA) at 10-4 M retarded the decline in pigment levels and promoted the decline in protein levels of radish leaf discs. ABA treatment also retarded the rise in the specific activity of the RNA fraction (calculated by counts per minute incorporated of 14C-8-adenine as a fraction of optical density at 260 nm) observed in water-treated control discs. The results indicated that ABA was primarily effective in enhancing senescence in the early stages following leaf excision. Thus the increase in RNA specific activity during an initial 24 h incubation period was especially pronounced with ABA treatment although there was no effect of the hormone on RNA level. Moreover, in contrast to control discs, the pigment levels declined markedly in ABA-treated discs in this period. When the discs had been incubated in water (“preaged”) for 3 or 5 days prior to ABA treatment, however, the hormone then had little effect on RNA metabolism and protein and pigment levels relative to the water control.
Data are collated from different experiments to show the changes in RNA, pigment and protein with ABA treatment during a 6 day senescence period.
It is considered that ABA is speeding up the natural changes in RNA metabolism possibly by affecting both RNA synthesis and degradation.
Similar content being viewed by others
References
Beevers, L.: Growth regulator control of leaf senescence in leaf discs of nasturtium (Tropaeolum majus). In: Biochemistry and physiology of plant growth substances, p. 1417–1435 (F. Wightman and G. Setterfield, eds.). Ottawa: Runge Press 1968.
Burdett, A.N., Wareing, P. F.: The effects of kinetin and contaminating bacteria on the incorporation of 32P-orthophosphate into various fractions of nucleic acids extracted from radish leaves. Planta (Berl.) 81, 88–96 (1968).
Cherry, J. H., Chroboczek, H., Carpenter, W. J. G., Richmond, A.: Nucleic acid metabolism in peanut cotyledons. Plant Physiol. 40, 582–587 (1965).
Clowes, F. A. L., Juniper, B. E.: Plant Cells, p. 112. Oxford: Blackwell Scientific Publications 1968.
Eilam, Y.: Permeability changes in senescing tissue. J. exp. Bot. 16, 614–627 (1965).
El-Antably, H. M. M., Wareing, P. F., Hillman, J.: Some physiological responses to d,l abscisin. Planta (Berl.) 73, 74–90 (1967).
Fletcher, R. A., Osborne, D. J.: Regulation of protein and nucleic acid synthesis by GA during leaf senescence. Nature (Lond.) 207, 1176–1177 (1965).
Glinka, Z., Reinhold, L.: Abscisic acid raises the permeability of plant cells to water. Plant Physiol. 48, 103–105 (1971).
Lewington, R. J., Talbot, M., Simon, E. W.: The yellowing of attached and detached cucumber cotyledons. J. exp. Bot. 18, 526–534 (1967).
Mackinney, G.: J. biol. Chem. 132, 91 (1940). Cited by Paech and Tracey in: Modern methods of plant analysis, IV, p. 143. Berlin-Göttingen-Heidelberg: Springer 1955.
Osborne, D. J.: The effect of kinetin on protein and nucleic acid metabolism in Xanthium leaves during senescence. Plant Physiol. 37, 595–602 (1962).
Osborne, D. J., Hallaway, H. M.: Role of auxins in the control of leaf senescence. In: 4th International conference of plant growth regulators, p. 329–340 (W. Klein, ed.). New York: Iowa State Press 1961.
Paranjothy, K., Wareing, P. F.: The effects of ABA, kinetin and 5-fluorouracil on RNA and protein synthesis in senescing radish leaf discs. Planta (Berl.) 99, 112–119 (1971).
Pietro, D. L., Sacher, J. A.: Control of ribonuclease and phosphatase by auxin and ABA during senescence of Rhoeo leaf sections. Plant Physiol. 46, 806–811 (1970).
Richmond, A. E., Lang, A.: The effect of kinetin on protein content and survival of detached Xanthium leaves. Science 125, 650–651 (1957).
Sacher, J. A.: Senescence: hormonal control of RNA and protein synthesis in excised bean pod tissue. Amer. J. Bot. 52, 841–848 (1962).
Srivastava, B. I. S., Ware, G.: The effect of kinetin on nucleic acids and nucleases of excised barley leaves. Plant Physiol. 40, 62–64 (1965).
Srivastava, B. I. S., Atkin, R. K.: Effect of second leaf removal or kinetin treatment on the nucleic acid metabolism of the senescing first seedling leaf of barley. Biochem. J. 107, 361–366 (1968).
Trewavas, A.: Relationship between plant growth hormones and nucleic acid metabolism. Progr. Phytochem. 1, 113–160 (1968).
Trewavas, A.: The turnover of nucleic acids in Lemna minor. Plant Physiol. 45, 742–751 (1970).
Wareing, P. F., Good, J., Potter, H., Pearson, J. A.: Preliminary studies on the mode of action of ABA. In: Plant Growth Regulators, p. 191–205. 31: Society of Chemical Industry Monograph 1968.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Colquhoun, A.J., Hillman, J.R. The effects of abscisic acid on senescence in leaf discs of radish, Raphanus sativus L.. Planta 105, 213–224 (1972). https://doi.org/10.1007/BF00385393
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00385393