Abstract
We have discovered that younger leaves do not exhibit the same large increase in photosynthesis as do older ones when the oxygen tension is lowered. This phenomenon was observed in various tobacco and citrus species and indicated less photo-respiration in young leaves. Activities of glycolate oxidase and of glyoxylate reductase were found to be significantly lower in younger leaves than in more mature ones from the same plant. Assays of glycolate content revealed the same trend. Levels of phosphoenolpyruvate carboxylase were only slightly higher in the younger leaves. This finding lessens the possibility of differing enzymatic pathways for CO2 fixation. It is concluded that the small photorespiratory activity of young leaves can be attributed to a lower activity of the photorespiratory enzymes and perhaps also to a slightly higher rate of internal recycling of CO2.
Full text
PDFSelected References
These references are in PubMed. This may not be the complete list of references from this article.
- Decker J. P. A Rapid, Postillumination Deceleration of Respiration in Green Leaves. Plant Physiol. 1955 Jan;30(1):82–84. doi: 10.1104/pp.30.1.82. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Decker J. P. Some Effects of Temperature and Carbon Dioxide Concentration on Photosynthesis of Mimulus. Plant Physiol. 1959 Mar;34(2):103–106. doi: 10.1104/pp.34.2.103. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Forrester M. L., Krotkov G., Nelson C. D. Effect of Oxygen on Photosynthesis, Photorespiration and Respiration in Detached Leaves. II. Corn and other Monocotyledons. Plant Physiol. 1966 Mar;41(3):428–431. doi: 10.1104/pp.41.3.428. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Forrester M. L., Krotkov G., Nelson C. D. Effect of oxygen on photosynthesis, photorespiration and respiration in detached leaves. I. Soybean. Plant Physiol. 1966 Mar;41(3):422–427. doi: 10.1104/pp.41.3.422. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hatch M. D., Slack C. R., Johnson H. S. Further studies on a new pathway of photosynthetic carbon dioxide fixation in sugar-cane and its occurrence in other plant species. Biochem J. 1967 Feb;102(2):417–422. doi: 10.1042/bj1020417. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Homann P. H. Studies on the manganese of the chloroplast. Plant Physiol. 1967 Jul;42(7):997–1007. doi: 10.1104/pp.42.7.997. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moss D. N., Krenzer E. G., Jr, Brun W. A. Carbon dioxide compensation points in related plant species. Science. 1969 Apr 11;164(3876):187–188. doi: 10.1126/science.164.3876.187. [DOI] [PubMed] [Google Scholar]
- Schmid G. H., Gaffron H. Light metabolism and chloroplast structure in chlorophyll-deficient tobacco mutants. J Gen Physiol. 1967 Jan;50(3):563–582. doi: 10.1085/jgp.50.3.563. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Slack C. R., Hatch M. D. Comparative studies on the activity of carboxylases and other enzymes in relation to the new pathway of photosynthetic carbon dioxide fixation in tropical grasses. Biochem J. 1967 Jun;103(3):660–665. doi: 10.1042/bj1030660. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tolbert N. E., Oeser A., Yamazaki R. K., Hageman R. H., Kisaki T. A survey of plants for leaf peroxisomes. Plant Physiol. 1969 Jan;44(1):135–147. doi: 10.1104/pp.44.1.135. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tolbert N. E., Yamazaki R. K., Oeser A. Localization and properties of hydroxypyruvate and glyoxylate reductases in spinach leaf particles. J Biol Chem. 1970 Oct 10;245(19):5129–5136. [PubMed] [Google Scholar]
- ZELITCH I. The isolation and action of crystalline glyoxylic acid reductase from tobacco leaves. J Biol Chem. 1955 Oct;216(2):553–575. [PubMed] [Google Scholar]
- ZELITCH I. The role of glycolic acid oxidase in the respiration of leaves. J Biol Chem. 1958 Dec;233(6):1299–1303. [PubMed] [Google Scholar]
- Zelitch I., Day P. R. Variation in photorespiration. The effect of genetic differences in photorespiration on net photosynthesis in tobacco. Plant Physiol. 1968 Nov;43(11):1838–1844. doi: 10.1104/pp.43.11.1838. [DOI] [PMC free article] [PubMed] [Google Scholar]