The photosynthetic response to elevated CO2 in high altitude potato species (Solanum curtilobum)
Carlos
Alberto
Martinez, Universidade de São Paulo, FFCLRP, Departamento de Biologia, carlosamh@ffclrp.usp.br
(Presenting)
Natalia
Olivo, Universidad de la Republica, Uruguay, nolivo@adinet.com.uy
Marco
Antonio
Oliva, UFV, Depto. de Biologia Vegetal, moliva@ufv.br
The photosynthetic responses of two potato species differing in origin, Solanum curtilobum (from high altitude) and Solanum tuberosum (from low altitude), to CO2 enrichment were studied in open-top chambers in a greenhouse. Plants were grown at either ambient (AC, 360 mmol mol-1) or ca. twice ambient (EC, 720 mmol mol-1) CO2 concentrations for 30 d. CO2 treatments started at the reproductive stage of the plants. There were similar patterns in the physiological response to CO2 enrichment in the two species. Stomatal conductance was reduced by 59 % in S. tuberosum and by 55 % in S. curtilobum, but such a reduction did not limit the rates of photosynthesis, which were increased by approximately 56 % in S. curtilobum and 53 % in S. tuberosum. The transpiration rate was reduced by 16 % in both potato species while instantaneous transpiration efficiency increased by 80 % in S. tuberosum and 90 % in S. curtilobum. Plants grown under EC showed 36 and 66 % increment in total dry biomass, whereas yields (dry mass of tubers) were increased by 40 and 85 % in S. tuberosum and S. curtilobum, respectively. Elevated CO2 concentration promoted productivity by increasing photosynthetic rate. These results suggest that S. tuberosum, cultivated around the world at low altitudes and S. curtilobum, endemic of the highland Andes, respond positively to elevated CO2 concentration during the tuberisation stage. / Supported by CNPq/CAPES/FAPEMIG
Submetido por Carlos Alberto Martinez em 18-MAR-2004
Tema Científico do LBA: CD (Armazenamento e Trocas de Carbono)