Abstract
Succulent stems of Cissus quadrangularis L. (Vitaceae) contain glutamine synthetase, glutamate synthase, and glutamate dehydrogenase. The CO2 and water gas exchanges of detached internodes were typical for Crassulacean acid metabolism plants. During three physiological phases, e.g. in the dark, in the early illumination period after stomata closure, and during the late light phase with the stomata wide open, 15NH4Cl was injected into the central pith of stem sections. The kinetics of 15N labeling in glutamate and glutamine suggested that glutamine synthetase was involved in the initial ammonia fixation. In the presence of methionine sulfoximine, an inhibitor of glutamine synthetase, the incorporation of 15N derived from 15NH4Cl was almost completely inhibited. Injections of amido-15N glutamine demonstrated a potential for 15N transfer from the amido group of glutamine into glutamate which was suppressed by the glutamate synthase inhibitor, azaserine. The evidence indicates that glutamine synthetase and glutamate synthase could assimilate ammonia and cycle nitrogen during all phases of Crassulacean acid metabolism.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chang N. K. Nitrate Assimilation and Crassulacean Acid Metabolism in Leaves of Kalanchoë fedtschenkoi Variety Marginata. Plant Physiol. 1981 Aug;68(2):464–468. doi: 10.1104/pp.68.2.464. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kanazawa T., Kirk M. R., Bassham J. A. Regulatory effects of ammonia on carbon metabolism in photosynthesizing Chlorella pyrenoidosa. Biochim Biophys Acta. 1970 Jun 30;205(3):401–408. doi: 10.1016/0005-2728(70)90106-4. [DOI] [PubMed] [Google Scholar]
- Knight T. J., Weissman G. S. Rhythms in glutamine synthetase activity, energy charge, and glutamine in sunflower roots. Plant Physiol. 1982 Dec;70(6):1683–1688. doi: 10.1104/pp.70.6.1683. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McNally S. F., Hirel B., Gadal P., Mann A. F., Stewart G. R. Glutamine Synthetases of Higher Plants : Evidence for a Specific Isoform Content Related to Their Possible Physiological Role and Their Compartmentation within the Leaf. Plant Physiol. 1983 May;72(1):22–25. doi: 10.1104/pp.72.1.22. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Suzuki A., Oaks A., Jacquot J. P., Vidal J., Gadal P. An electron transport system in maize roots for reactions of glutamate synthase and nitrite reductase : physiological and immunochemical properties of the electron carrier and pyridine nucleotide reductase. Plant Physiol. 1985 Jun;78(2):374–378. doi: 10.1104/pp.78.2.374. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ting I. P., Sternberg L. O., Deniro M. J. Variable Photosynthetic Metabolism in Leaves and Stems of Cissus quadrangularis L. Plant Physiol. 1983 Mar;71(3):677–679. doi: 10.1104/pp.71.3.677. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Walker K. A., Givan C. V., Keys A. J. Glutamic Acid metabolism and the photorespiratory nitrogen cycle in wheat leaves: metabolic consequences of elevated ammonia concentrations and of blocking ammonia assimilation. Plant Physiol. 1984 May;75(1):60–66. doi: 10.1104/pp.75.1.60. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Woo K. C., Morot-Gaudry J. F., Summons R. E., Osmond C. B. Evidence for the Glutamine Synthetase/Glutamate Synthase Pathway during the Photorespiratory Nitrogen Cycle in Spinach Leaves. Plant Physiol. 1982 Nov;70(5):1514–1517. doi: 10.1104/pp.70.5.1514. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yamaya T., Oaks A., Matsumoto H. Characteristics of glutamate dehydrogenase in mitochondria prepared from corn shoots. Plant Physiol. 1984 Dec;76(4):1009–1013. doi: 10.1104/pp.76.4.1009. [DOI] [PMC free article] [PubMed] [Google Scholar]