Hostname: page-component-76fb5796d-5g6vh Total loading time: 0 Render date: 2024-04-25T15:28:49.880Z Has data issue: false hasContentIssue false

Relief of thermoinhibition in Grand Rapids lettuce seeds by oxygen plus kinetin and their effects on respiration, content of ethanol and ATP and synthesis of ethylene

Published online by Cambridge University Press:  19 September 2008

J. G. Chris Small*
Affiliation:
Department of Botany and Genetics, University of the Orange Free State, PO Box 339, Bloemfontein 9300, South Africa
Colleen Schultz
Affiliation:
Department of Botany and Genetics, University of the Orange Free State, PO Box 339, Bloemfontein 9300, South Africa
Elbie Cronje
Affiliation:
Department of Botany and Genetics, University of the Orange Free State, PO Box 339, Bloemfontein 9300, South Africa
*
* Correspondence

Abstract

Seed germination of Grand Rapids lettuce (Lactuca sativa L.) was inhibited at 38°C (thermoinhibition). Thermoinhibition was totally relieved by a combination of 100% oxygen and 10 mg I−1 kinetin, to a lesser extent by a combination of oxygen and ethylene but not at all by oxygen plus GA3. The combination of oxygen with kinetin or ethylene was more effective in preventing thermoinhibition than a combination of all three hormones and CO2 in air. The beneficial effect of oxygen plus kinetin was not related to either increased production of CO2 or ethylene by the seeds. In air, germination was partially inhibited by 2-aminoethoxyvinyl glycine (AVG) or 2,5-norbornadiene (NBD) and totally inhibited by AVG plus NBD. Oxygen plus kinetin almost completely alleviated their inhibitory effects. It was concluded that oxygen plus kinetin caused seeds to bypass an ethylene requirement for germination or increased the sensitivity of seeds to ethylene. In air at 38°C, seeds exhibited a high level of ethanolic fermentation, while in oxygen plus kinetin they respired aerobically. At 38°C in air, contents of ATP and total adenylates were reduced, while in seeds treated with oxygen plus kinetin these contents were similar or higher than in 25°C controls. A similar response was also observed for adenylate energy charge. It was concluded that part of the mechanism of thermoinhibition could be the failure of ATP content to reach a sufficient level to satisfy the requirement for germination at 38°C. It appeared possible that the prevention of thermoinhibition by oxygen plus kinetin could be related to increased ATP content in seeds caused by this treatment.

Type
Research Papers
Copyright
Copyright © Cambridge University Press 1993

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Borthwick, H.A. and Robbins, W.W. (1928) Lettuce seed and its germination. Hilgardia 3, 275302.CrossRefGoogle Scholar
Davis, W.E. (1924) The germination of lettuce seed. Proceedings of the North American Association of Seed Analysts 16, 7173.Google Scholar
Esashi, Y., Kawabe, K., Isuzugawa, K. and Ishizawa, K. (1988) Interrelations between carbon dioxide and ethylene on the stimulation of cocklebur seed germination. Plant Physiology 86, 3943.CrossRefGoogle ScholarPubMed
Katoh, H. and Esashi, Y. (1975) Dormancy and impotency of cocklebur seeds II. Phase sequence in germination process. Plant and Cell Physiology 16, 697706.Google Scholar
Keys, R.D., Smith, O.E., Kumamoto, J. and Lyon, J.L. (1975) Effect of gibberellic acid, kinetin and ethylene plus carbon dioxide on the thermodormancy of lettuce seed (Lactuca sativa L. cv. Mesa 659). Plant Physiology 56, 826829.CrossRefGoogle ScholarPubMed
Kimmerer, T.W. and Kozlowski, T.T. (1982) Ethylene, ethane, acetaldehyde, and ethanol production by plants under stress. Plant Physiology 69, 840847.CrossRefGoogle ScholarPubMed
Kristie, D.N., Bassi, P.K. and Spencer, M.S. (1981) Factors affecting the induction of secondary dormancy in lettuce. Plant Physiology 67, 12241229.CrossRefGoogle ScholarPubMed
Machabée, S. and Saini, H.S. (1991) Differences in the requirement for endogenous ethylene during germination of dormant and non-dormant seeds of Chenopodium album L. Journal of Plant Physiology 138, 97101.CrossRefGoogle Scholar
Negm, F.B., Smith, O.E. and Kumamoto, J. (1972) Interaction of carbon dioxide and ethylene in overcoming thermodormancy of lettuce seeds. Plant Physiology 49, 869872.CrossRefGoogle ScholarPubMed
Negm, F.B., Smith, O.E. and Kumamoto, J. (1973) The role of phytochrome in an interaction with ethylene and carbon dioxide in overcoming lettuce seed thermodormancy. Plant Physiology 51, 10891094.CrossRefGoogle Scholar
Owens, L.D., Lieberman, M. and Kunishi, A.T. (1971) Inhibition of ethylene production by rhizobitoxine. Plant Physiology 48, 14.CrossRefGoogle ScholarPubMed
Raymond, P. and Pradet, A. (1980) Stabilization of adenine nucleotide ratios at various values by an oxygen limitation of respiration in germinating lettuce (Lactuca sativa) seeds. Biochemical Journal 190, 3944.CrossRefGoogle ScholarPubMed
Raymond, P., Al-Ani, A. and Pradet, A. (1983) Low contribution of non-respiratory pathways in ATP regeneration during early germination of lettuce seeds. Physiologie Végétale 21, 677687.Google Scholar
Riley, G.J.P. (1981) Effects of high temperature on the germination of maize (Zea mays L.). Planta 151, 6874.CrossRefGoogle ScholarPubMed
Rudnicki, R.M., Braun, J.W. and Khan, A.A. (1978) Low pressure and ethylene in lettuce seed germination. Physiologia Plantarum 43, 189194.CrossRefGoogle Scholar
Saini, H.S., Consolacion, E.D., Bassi, P.K. and Spencer, M.S. (1986) Requirement for ethylene synthesis and action during relief of thermoinhibition of lettuce seed germination by combinations of gibberellic acid, kinetin and carbon dioxide. Plant Physiology 81, 950953.CrossRefGoogle ScholarPubMed
Sisler, E.C. and Yang, S.F. (1984) Anti-ethylene effects of cis-2-butene and cyclic olefins. Phytochemistry 12, 27652768.CrossRefGoogle Scholar
Small, J.G.C., Potgieter, G.P. and Botha, F.C. (1989) Anoxic seed germination of Erythrina caffra: Ethanol fermentation and response to metabolic inhibitors. Journal of Experimental Botany 40, 375381.CrossRefGoogle Scholar
Thompson, D.A., Cox, S.A. and Sanderson, R.H. (1979) Characterization of germination response to temperature of lettuce (Lactuca sativa L.) achenes. Annals of Botany 43, 319334.CrossRefGoogle Scholar
Umbreit, W.W., Burris, R.H. and Stauffer, J.F. (1972) pp 101110 in Manometric Biochemical Techniques. 5th Ed. Mineapolis, Burgess Publ. Co.Google Scholar
Vidaver, W. and Hsiao, A.I. (1975) Secondary dormancy in light-sensitive lettuce seeds incubated anaerobically or at elevated temperature. Canadian Journal of Botany 53, 25572560.CrossRefGoogle Scholar