Resumo

SAUGIER, B.  e  PONTAILLER, J.Y.. Carbon global cycle and its consequences on photosynthesis in the Bolivian Altiplano. Ecología en Bolivia [online]. 2006, vol.41, n.3, pp.71-85. ISSN 1605-2528.

The global carbon cycle is described considering the carbon fluxes between the atmosphere and the terrestrial biosphere, and the perturbations due to human activity: nitrogen deposition, increased atmospheric CO₂ and induced climatic warming. These global changes increase plant production and then carbon storage in tree biomass and soil organic matter. The Bolivian Altiplano with long fallow agrosystems is affected by these global changes as all other terrestrial ecosystems. The leaf photosynthetic response to light and CO₂ was measured for a few plant species of fallow in the Bolivian Altiplano. As expected, maximum photosynthesis is high for pioneer plants and low for plants of late succession. Wild species (Chondrosum simplex, Erodium cicutarium, Lupinus otto-buchtienii, Baccharis incarum, Parastrephia lepidophylla, Stipa ichu, Aristida asplundii) exhibit higher photosynthetic rates than quinoa (Chenopodium quinoa) crop, which is surprising. In each species leaf photosynthesis strongly increases with CO₂, almost doubling when CO₂ is artificially doubled. A rise in atmospheric CO₂ may increase plant productivity during fallow and thus induce a reduction of fallow duration in the Bolivian Altiplano.

Palavras-chave : Carbon balance; Climatic change; Biomass; Photosynthesis; Bolivian Altiplano.

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