Abstract
Russet spotting (RS), consisting of numerous small brown spots on the midrib of head lettuce (Lactuca sativa), is a physiological disorder induced by exposure to ethylene. In leaves suffering RS, the increase in spotting was accompanied by a parallel increase in the amount of phenolic compounds. Of these, chlorogenic acid and isochlorogenic acid were identified. Ethylene induced high phenylalanine ammonia-lyase (PAL) activity and RS formation in the susceptible cultivar Salinas, but not in the resistant cultivar Calmar. In the absence of ethylene neither significant PAL induction nor RS occurred. No correlation was found between the increase in polyphenol oxidase or peroxidase and the development of RS. The increase in PAL activity, however, was closely correlated with the development of RS. The increase in PAL activity preceded the development of RS, and the extent of RS was directly related to the level of PAL. Three temperatures (0.5, 5.5, and 12.5 C) were compared on the basis of their influence on both RS and PAL induction. At the lowest temperature (0.5 C) neither PAL induction nor RS occurred to a significant extent. At the highest temperature (12.5 C) an initial rapid increase in PAL activity and an earlier development of spotting were observed, but subsequently there was a decrease in both PAL activity and the rate of development of RS. At the medium temperature (5.5 C) both PAL activity and RS increased progresively with time. The decline of PAL activity at a higher temperature might be attributed to inactivation of the enzyme. Thus, a temperature favorable for induction of PAL activity by ethylene was also favorable for RS. These observations indicate a close interrelationship between the induction of PAL activity and the development of RS in response to ethylene, and suggest a causal relationship between the two events. PAL serves as a useful biochemical marker for the RS reaction.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chalutz E. Ethylene-induced Phenylalanine Ammonia-Lyase Activity in Carrot Roots. Plant Physiol. 1973 Jun;51(6):1033–1036. doi: 10.1104/pp.51.6.1033. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Engelsma G., van Bruggen J. M. Ethylene production and enzyme induction in excised plant tissues. Plant Physiol. 1971 Jul;48(1):94–96. doi: 10.1104/pp.48.1.94. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hyodo H., Yang S. F. Ethylene-enhanced Synthesis of Phenylalanine Ammonia-Lyase in Pea Seedlings. Plant Physiol. 1971 Jun;47(6):765–770. doi: 10.1104/pp.47.6.765. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hyodo H., Yang S. F. Ethylene-enhanced formation of cinnamic acid 4-hydroxylase in excised pea epicotyl tissue. Arch Biochem Biophys. 1971 Mar;143(1):338–339. doi: 10.1016/0003-9861(71)90216-5. [DOI] [PubMed] [Google Scholar]
- KOUKOL J., CONN E. E. The metabolism of aromatic compounds in higher plants. IV. Purification and properties of the phenylalanine deaminase of Hordeum vulgare. J Biol Chem. 1961 Oct;236:2692–2698. [PubMed] [Google Scholar]
- ROBERTS E. A. H., WOOD D. J. The polyphenols and amino acids of tobacco leaf. Arch Biochem Biophys. 1951 Sep;33(2):299–303. doi: 10.1016/0003-9861(51)90109-9. [DOI] [PubMed] [Google Scholar]
- Riov J., Monselise S. P., Kahan R. S. Ethylene-controlled Induction of Phenylalanine Ammonia-lyase in Citrus Fruit Peel. Plant Physiol. 1969 May;44(5):631–635. doi: 10.1104/pp.44.5.631. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schlichter D. Chemischer Nachweis der Ubernahme anemoneneigener Schutzstoffe durch Anemonenfische. Naturwissenschaften. 1970 Jun;57(6):312–312. doi: 10.1007/BF00609395. [DOI] [PubMed] [Google Scholar]
- Zucker M. Sequential Induction of Phenylalanine Ammonia-lyase and a Lyase-inactivating System in Potato Tuber Disks. Plant Physiol. 1968 Mar;43(3):365–374. doi: 10.1104/pp.43.3.365. [DOI] [PMC free article] [PubMed] [Google Scholar]