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Metabolism and distribution of grasses in tropical flooded savannas in Venezuela

Published online by Cambridge University Press:  10 July 2009

Ernesto Medina  and
Norma Motta
Ernesto Medina
Affiliation:
Centro de Ecología, Instituto Venezolano de Investigaciones Cientificas, IVICAptdo. 21827Caracas 1020-AVenezuela
Norma Motta
Affiliation:
Centro de Ecología, Instituto Venezolano de Investigaciones Cientificas, IVICAptdo. 21827Caracas 1020-AVenezuela
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Abstract

Flooded savannas in south-west Venezuela consist of seasonal, marshy and flooded grassland communities, the distribution of which depends on soil level. Seasonal grasslands are dominated by tuft-forming, rhizomatous C4-grasses (exemplified by Paspalum chaffanjonii in this study), while flooded grasslands are dominated by stoloniferous grasses which develop rooted, floating culms during the rainy season (Leersia hexandra and Hymenachne amplexi-caulis). The interface between these two communities is a marshy grassland dominated by stoloniferous grass species which tolerate flooding to a depth of 10 to 25 cm (Panicum laxum and Leersia hexandra). All perennial grass species in flooded grasslands behave as typical C3 plants, while marshy grasslands are dominated by Panicum laxum, a species with reduced photo-respiration, low RuBP/PEP-carboxylase ratios, and low absolute RuBP-carboxylase activity compared to C3 grasses. It also has lower photosynthetic rates than the other grass species. Hymenachne amplexicaulis appears to be the least drought tolerant from the species selected, in accordance with its distribution in the wettest side of the flooding gradient studied. The other species showed marked reduction in relative water content and pronounced increase in leaf proline content in drought experiments lasting 6 to 30 days. Alcohol dehydrogenase increased markedly in response to anaerobiosis in the root environment in the tuft forming grasses, while the stoloniferous species with ascending culms were least affected by this treatment, probably as a result of better aeration inside the culms and also to the production of adventitious roots in upper nodes. Nitrate reductase activity increased as a result of anaerobiosis in the roots but not in the leaves, of all species except Leersia hexandra. No difference among the species was found in malate accumulation, or the activity of malic enzyme.

Keywords

anaerobiosisdrought toleranceflooded-grasslandsphotosynthetic-intermediatestropical savannasVenezuela
Type
Research Article
Information
Journal of Tropical Ecology , Volume 6 , Issue 1 , February 1990 , pp. 77 - 89
Copyright
Copyright © Cambridge University Press 1990

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References

LITERATURE CITED

Barnett, N. M. & Naylor, A. W. 1966. Amino acid and protein metabolism in Bermuda grass during water stress. Plant Physiology 41:1222–1230.CrossRefGoogle ScholarPubMed
Bates, L. S., Waldren, R. P. & Teare, I. D. 1973. Rapid determination of free proline for water-stress studies. Plant and Soil 39:205–207.Google Scholar
Bergmeyer, H. U. 1963. Methods of enzymatic analysis. Academic Press.Google Scholar
Björkman, O. & Gauhl, E. 1969. Carboxydismutase activity in plants with and without &β-carboxyla-tion photosynthesis. Planta 88:197–203.CrossRefGoogle ScholarPubMed
Blevins, D. G., Lowe, R. H. & Staples, L. 1976. Nitrate reductase in barley roots under sterile, low oxygen conditions. Plant Physiology 57:458–459.CrossRefGoogle ScholarPubMed
Brown, R. H. 1980. Photosynthesis of grass species differing in carbon dioxide fixation pathways. IV. Analysis of reduced oxygen response in Panicum milioides and Panicum schenckii. Plant Physiology 65:346–349.Google Scholar
Brown, R. H. & Brown, W. V. 1975. Photosynthetic characteristics of Panicum milioides, a species with reduced photorespiration. Crop Science 15:681–685.CrossRefGoogle Scholar
Bulla, L. A., Pacheco, J. & Miranda, R. 1980a. Ciclo estacional de la biomasa verde, muerta y ra&íces en una sabana inundada de estero en Mantecal (Venezuela). Acta Cient&ífica Venezolana 31:339–344.Google Scholar
Bulla, L. A., Pacheco, J. & Miranda, R. 1980b. Producci&ón, descomposici&ón, flujo de materiaorg&ánica y diversidad en una sabana de banco del M&ódulo Experimental de Mantecal (Edo., Apure, Venezuela). Acta Cient&ífica Venezolana 31:331–338.Google Scholar
Coombs, J. & Hall, D. O. (1982). Techniques in bioproductivity and photosynthesis. Pergamon Press, Oxford.Google Scholar
Crawford, R. M. M. (1982). Physiological responses to flooding. Pp. 453–478 in Lange, O. L., Nobel, P. S., Osmond, C. B. & Ziegler, H. (eds). Encyclopedia of plant physiology, New Series, Vol. 12B. Springer Verlag, Berlin.Google Scholar
Crawford, R. M. M. & Tyler, P. D. 1969. Organic acid metabolism in relation to flooding tolerance in roots. Journal of Ecology 57:235–244.Google Scholar
Escobar, A. & Gonz&ález-Jim&énez, E. 1979. La production primaire de la sabane inondable d'Apure (Venezuela). Geo-Eco-Trop 3:53–70.Google Scholar
Garcia-Novo, F. & Crawford, R. M. M. 1973. Soil aeration, nitrate reduction and flooding tolerancein higher plants. New Phytologist 72:1031–1039.Google Scholar
Goldstein, L. D., Ray, T., Kestler, D. P., Mayne, B. C., Brown, R. H. & Black, C. C. 1976. Biochemical characterization of Panicum species which are intermediate between C3 and C4 photosynthesis plants. Plant Science Letters 6:85–90.Google Scholar
Hoagland, D. R. &: Arnon, D. I. 1950. The water culture method for growing plants without soil.California Agricultural Experiment Station. Circular No. 347.Google Scholar
Jackson, M. B. & Drew, M. C. 1984. Effects of flooding on growth and metabolism of herbaceous plants. Pp. 47–128 in Kozlowski, T. T. (ed.). Flooding and plant growth Academic Press, Inc.Google Scholar
John, C. D. & Greenway, H. 1976. Alcoholic fermentation and activity of some enzymes in ric roots under anaerobiosis. Australian Journal of Plant Physiology 3:325–336.Google Scholar
Jones, H. G. 1973. Moderate term water stresses and associated changes in some photosynthetic parameters in cotton. New Phytologist 72:1095–1105.CrossRefGoogle Scholar
Ku, S. B. & Edwards, G. E. 1978. Photosynthetic efficiency of Panicum hians and Panicum milioides in relation to C3 and C4 plants. Plant Cell Physiology 19:665–675.Google Scholar
Lowry, O. H., Rosenbrough, N. J., Farr, A. L. & Randall, R. J. 1951. Protein measurement with the Folin phenol reagent. Journal of Biological Chemistry 193:265–276.Google Scholar
McMannon, M. & Crawford, R. M. M. 1971. A metabolic theory of flooding tolerance: the significance of enzyme distribution and behaviour. New Phytologist 70:299–306.CrossRefGoogle Scholar
Medina, E., Bifano, T. de & Delgado, M. 1976. Diferenciaci&ón fotosint&ética en plantas superiores. Interciencia 1:96–104.Google Scholar
Monson, R. K., Edwards, G. E. & Ku, S. B. 1984. C3-C4 intermediate photosynthesis in plants. Bio Science 34:563–574.Google Scholar
Motta, N. 1978. Adaptaciones metab&ólicas en gram&íneas de zonas inundables. Tesis M.Sc. IVIC. Caracas.Google Scholar
Plaut, Z. 1971. Inhibition of photosynthetic carbon dioxide fixation in isolated spinach chloroplasts exposed to reduced osmotic potentials. Plant Physiology 48:591–595.Google Scholar
Ramia, M. 1967. Tipos de sabanas en los llanos de Venezuela. Bolet&ín de la Sociedad Venezolana de Ciencias Naturales 27 (112):264–288.Google Scholar
Ramia, M. 1974. Estudio ecol&ógico del m&ódulo experimental de Mantecal. Bolet&ín Sociedad Venezolana de Ciencias Naturales 31 (128–129): 117–142.Google Scholar
Ramia, M. & Delascio, F. 1982. Ecolog&ía de las sabanas del estado Cojedes: reconocimiento flor&ístico y fenolog&ía. Memoria Sociedad Ciencias Naturales La Salle No. 117:61–134.Google Scholar
Sarmiento, G. 1984. The ecology of neotropical savannas. Harvard University Press, Cambridge, Mass.Google Scholar
Wignarajah, K. & Greenway, H. 1976. Effect of anaerobiosis on activities of alcohol dehydrogenase and pyruvate decarboxylase in roots of Zea mays. New Phytologist 77:575–584.CrossRefGoogle Scholar
Wignarajah, K., Greenway, H. & John, C. D. 1976. Effect of waterlogging on growth and activity of alcohol dehydrogenase in barley and rice. New Phytologist 77:585–592.Google Scholar
Williams, G. J. III & Markley, J. L. 1973. The photosynthetic pathway types of North American shortgrass pra&ìr&ìe species and some ecological implications. Photosynthetica 7:262–270.Google Scholar