, Volume 97, Issue 2, pp 193–201 | Cite as

Leaf and canopy photosynthetic CO2 uptake of a stand of Echinochloa polystachya on the Central Amazon floodplain

Are the high potential rates associated with the C4 syndrome realized under the near-optimal conditions provided by this exceptional natural habitat?
  • M. T. F. Piedade
  • S. P. Long
  • W. J. Junk
Original Paper


The C4 grass Echinochloa polystachya, which forms dense and extensive monotypic stands on the Varzea floodplains of the Amazon region, provides the most productive natural higher plant communities known. The seasonal cycle of growth of this plant is closely linked to the annual rise and fall of water level over the floodplain surface. Diurnal cycles of leaf photosynthesis and transpiration were measured at monthly intervals, in parallel with measurements of leaf area index, canopy light interception and biomass. By artificial manipulation of the light flux incident on leaves in the field light-response curves of photosynthesis at the top and near to the base of the canopy were generated. Fitted light-response curves of CO2 uptake were combined with information of leaf area index, incident light and light penetration of the canopy to estimate canopy rates of photosynthesis. Throughout the period in which the floodplains were submerged photosynthetic rates of CO2 uptake (A) for the emergent leaves were high with a mean of c. 30 μmol m-2 s-1 at mid-day and occasional values of 40 μmol m-2 s-1. During the brief dry phase, when the floodplain surface is uncovered, there was a significant depression of A, with mid-day mean values of c. 17 μmol m-2 s-1. This corresponded with a c. 50% decrease in stomatal conductance, and a c. 35% depression in the ratio of the leaf inter-cellular to external CO2 concentration (ci/ca). During the dry phase, a midday depression of rates of CO2 assimilation was observed. The lowest leaf area index (F) was c. 2 in November–December, when the flood plain was dry, and again in May, when the rising floodwaters were submerging leaves faster than they were replaced. The maximum F of c. 5 was in August when the floodwaters were receding rapidly. Canopy light interception efficiency varied from 0.90 to 0.98. Calculated rates of canopy photosynthesis exceeded 18 mol C m-2 mo-1 throughout the period of flooding, with a peak of 37 mol C m-2 mo-1 in August, but declined to 13 mol C m-2 mo-1 in November during the dry phase. Estimated uptake of carbon by the canopy from the atmosphere, over 12 months, was 3.57 kg C m-2. This was insufficient to account for the 3.99 kg C m-2 of net primary production, measured simultaneously by destructive harvesting. It is postulated that this discrepancy might be accounted for by internal diffusion of CO2 from the CO2-rich waters and sediments via the roots and stems to the sites of assimilation in the leaves.

Key words

Amazon C4 photosynthesis Carbon cycle Echinochloa polystachya River floodplain 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Biscoe PV, Gallagher JN (1977) Weather, dry matter production and yield. In: Landsberg JJ, Cutting CV (eds) Environmental effects on crop physiology. Academic Press, London, pp 75–100Google Scholar
  2. Björkman O, Demmig B (1987) Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77K among vascular plants of diverse origins. Planta 170:489–504Google Scholar
  3. Bliss CI, James AT (1966) Fitting the rectangular hyperbola. Biometrics 22:573–602Google Scholar
  4. Charles-Edwards DA (1982) Physiological determinants of crop growth. Academic Press, SydneyGoogle Scholar
  5. Day W (1985) Water vapour measurement and control. In: Marshall B, Woodward FI (eds) Instrumentation for environmental physiology. Cambridge University Press, Cambridge, pp 59–78Google Scholar
  6. Demmig-Adams B, Adams WWI, Winter K, Meyer A, Schreiber U, Pereira JS, Krüger A, Czygan F-C, Lange OL (1989) Photochemical efficiency of photosystem II, photon yield of O2 evolution, photosynthetic capacity, and carotenoid composition during the midday depression of net CO2 uptake in Arbutus unedo growing in Portugal. Planta 177:377–387Google Scholar
  7. Doliner LH, Joliffe PA (1979) Ecological evidence concerning the adaptive significance of the C4 dicarboxylic acid pathway of photosynthesis. Oecologia 38:23–34Google Scholar
  8. Ehleringer J, Pearcy RW (1983) Variation in quantum yield for CO2 uptake among C3 and C4 plants. Plant Physiol 73:555–559Google Scholar
  9. Field CB (1983) Allocating leaf nitrogen for the maximization of carbon gain: leaf age as a control on the allocation program. Oecologia 56:341–347Google Scholar
  10. Forseth IN, Norman JM (1993) Modelling of solar irradiance, leaf energy budget and canopy photosynthesis. In: Hall DO, Scurlock JMO, Bolhàr-Nordenkampf HR, Leegood RC, Long SP (eds) Photosynthesis and productivity in a changing environment. Chapman and Hall, London, pp 207–219Google Scholar
  11. Furch K (1984) Seasonal variation of major cation content of the varzea-lake Lago Camaleão, middle Amazon, Brazil, in 1981 and 1982. Verh Internat Verein Limnol 22:1288–1293Google Scholar
  12. Furch K, Junk WJ (1984) Dissolved carbon in a floodplain lake of the Amazon and the river channel. In: Degens ETH, Kempe S, Herrera R (eds) Transport of carbon and minerals in major world rivers. UNEP/SCOPE/Geologisches und Palaeontologisches Institut, Hamburg, pp 267–283Google Scholar
  13. Hedges JI, Clark WA, Quay PD, Richey JE, Devol AH, Santos UM (1986) Compositions and fluxes of particulate organic material in the Amazon river. Limnol Oceanogr 31:717–738Google Scholar
  14. Houghton JT, Jenkins GJ, Ephraums JJ (eds) (1990) Climate change: the IPCC scientific assessment. Cambridge University Press, CambridgeGoogle Scholar
  15. Jones MB (1987) Wetlands. In: Baker NR, Long SP (eds) Photosynthesis in contrasting environments. Elsevier, Amsterdam, pp 103–138Google Scholar
  16. Jones MB, Long SP, Roberts MJ (1992) Synthesis and conclusions. In: Long SP, Jones MB, Roberts MJ (eds) Primary productivity of grass ecosystems of the tropics and subtropics. Chapman and Hall, London, pp 212–255Google Scholar
  17. Junk WJ (1993) Wetlands of tropical South-America. In: Whigham D, Hejny S, Dykyjová D (eds) Wetlands of the world. Kluwer, Dordrecht, pp 679–739Google Scholar
  18. Junk WJ, Howard-Williams C (1984) Ecology of aquatic macrophytes in Amazonia. In: Sioli H (eds) The Amazon-limnology and landscape ecology of a mighty tropical river and its basin. Junk, Dordrecht, pp 269–293Google Scholar
  19. Junk WJ, Bayley PB, Sparks RE (1989) The flood-pulse concept in river-floodplain systems. Can Spec Publ Fish Aquat Sci 106:110–127Google Scholar
  20. Körner C, Scheel JA, Bauer H (1979) Maximum leaf diffusive conductance in vascular plants. Photosynthetica 13:45–82Google Scholar
  21. Long SP (1985) Leaf gas exchange. In: Barber J, Baker NR (eds) Photosynthetic mechanisms and the environment. Elsevier, Amsterdam, pp 453–499Google Scholar
  22. Long SP (1986) Instrumentation for the measurement of CO2 assimilation by crop leaves. In: Gensler WG (eds) Advanced agricultural instrumentation. Nijhoff, Dordrecht, pp 39–91Google Scholar
  23. Long SP (1991) Modification of the response of photosynthetic productivity to rising temperature by atmospheric CO2 concentrations: has its importance been underestimated? Plant Cell Environ 14:729–740Google Scholar
  24. Long SP, Hällgren J-E (1993) measurement of CO2 assimilation by plants in the field and the laboratory. In: Hall DO, Scurlock JMO, Bolhàr-Nordenkampf HR, Leegood RC, Long SP (eds) Photosynthesis and productivity in a changing environment. Chapman and Hall, London, pp 129–167Google Scholar
  25. Long SP, Postl WF, Bolhár-Nordenkampf HR (1993) Quantum yields for uptake of carbon dioxide in C3 vascular plants of contrasting habitats and taxonomic groupings. Planta 189:226–234Google Scholar
  26. Ludlow MM, Wilson GL (1971) Photosynthesis of tropical pasture plants 1. Illuminance, carbon dioxide concentration, leaf temperature, and leaf-air vapour pressure difference. Aust J Biol Sci 24:449–470Google Scholar
  27. McCree KJ (1974) Equations for the rate of dark respiration of white clover and grain sorghum, as functions of dry weight, photosynthetic rate, and temperature. Crop Sci 14:509–514Google Scholar
  28. McMurtrie RE (1993) Modelling of canopy carbon and water balance. In: Hall DO, Scurlock JMO, Bolhàr-Nordenkampf HR, Leegood RC, Long SP (eds) Photosynthesis and productivity in a changing environment. Chapman and Hall, London, pp 220–231Google Scholar
  29. Monteith JL, Unsworth MH (1990) Principles of environmental physics, 2nd edn. Edward Arnold, LondonGoogle Scholar
  30. Norman JM (1980) Interfacing leaf and canopy light interception models. In: Hesketh JD, Jones JW (eds) Predicting photosynthesis for ecosystem models. CRC Press, Boca Raton, pp 49–67Google Scholar
  31. Ögren E (1988) Photoinhibition of photosynthesis in willow leaves under field conditions. Planta 175:229–236Google Scholar
  32. Parkinson KJ (1985) A simple method for determining the boundary layer resistance in leaf cuvettes. Plant Cell Environ 8:223–226Google Scholar
  33. Piedade MTF, Junk WJ, Long SP (1991) The productivity of the C4 grass Echinochloa polystachya on the Amazon floodplain. Ecology 72:1456–1463Google Scholar
  34. Piedade MTF, Junk WJ, Mello JAN de (1992) A floodplain grassland of the central Amazon. In: Long SP, Jones MB, Roberts MJ (eds) Primary productivity of grass ecosystems of the tropics and subtropics. Chapman and Hall, London, pp 127–158Google Scholar
  35. Ribeiro M, Adis J (1984) Local rainfull variability — a potential bias for bioecological studies of the central Amazon. Acta Amazon 14:159–174Google Scholar
  36. Sokal RR, Rohlf FJ (1981) Biometry, 2nd edn. WH Freeman, New YorkGoogle Scholar
  37. Teeri JA (1988) Interaction of temperature and other environmental variables influencing plant distribution. In: Long SP, Woodward FI (eds) Plants and temperature. Company of Biologists, Cambridge, pp 77–89Google Scholar
  38. Uchijima Z (1976) Rice and maize. In: Monteith JL (ed) Vegetation and the atmosphere, vol 2. Academic Press, London, pp 33–64Google Scholar
  39. Wofsy SC, Harriss RC, Kaplan WA (1988) Carbon dioxide in the atmosphere over the Amazon basin. J Geophys Res 93:1377–1388Google Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • M. T. F. Piedade
    • 1
  • S. P. Long
    • 2
  • W. J. Junk
    • 3
  1. 1.Instituto Nacional de Pesquisas da Amazonia-CPBAManausBrazil
  2. 2.Dept. of BiologyUniversity of EssexColchesterUK
  3. 3.Max-Planck Institut für LimnologieAG TropenökologiePlönGermany

Personalised recommendations