Ramalho, J.C., Semedo, J.N., Pais, I.P., Scotti-Campos, P., Rodrigues, A.P., Fortunato, A.F., Leitão, A.E., Lopes, E., Palos, I., Silva, M.J., Goulao, L., Batista-Santos, P., Ribeiro-Barros, A.I., Simões-Costa, M.C., Martins, L.D., Tomaz, M.A., Maia, R., Máguas, C., Pessoa, M.F., Reboredo, F.H., Lidon, F.C., Sanglard, L.M., Morais, L.E., Araújo, W.L., Ghini, R., DaMatta, F.M. (2015) A glimpse of climate change impact on C. arabica L. and C. canephora Pierre ex A. Froehner Physiology – the combined effects of enhanced growth CO2 and temperature. Proceedings of the 25th International Conference on Coffee Science, Association for Science and Information on Coffee (ASIC), Armenia, Colombia, 42-49.
The effective impact of climate changes on the coffee plant physiology, promoted by enhanced air [CO2] and global warming remain to be fully elucidated through biological studies. Therefore, this work aims at linking important coffee physiological responses to environmental changes of enhanced growth [CO2] and temperature on genotypes from the two major producing species. Potted plants from C. arabica cv. IPR 108 and of C. canephora cv. Conilon Clone 153 were grown under environmental controlled conditions, either at 380 or 700 µL CO2 L-1 air, for 1 year, without water, nutrient or root development restrictions. After that the temperature was gradually increased from 25/20 ºC (day/night) up to 42/34 ºC. The long-term impacts of enhanced growth [CO2] and enhanced temperature on the photosynthetic functioning were assessed at 25/20 ºC, 31/25 ºC, 37/30 ºC and 42/34 ºC, through leaf gas exchanges (rates of net photosynthesis, Pn, stomatal conductance, gs, transpiration, Tr, and photosynthetic capacity, Amax), instantaneous water use efficiency (iWUE), fluorescence parameters (photochemical efficiency of the photosystem II under dark, Fv/Fm, and light, Fv’/Fm’, conditions, as well as the photochemical, qP, and non-photochemical, NPQ, quenchings, and quantum yield of the linear electron transport, φe), photosynthetic pigments (chlorophyll and carotenoids) and some molecules with antioxidant role (ascorbate and α- tocopherol). The results showed that enhanced [CO2] stimulates photosynthetic functioning, without negative down-regulation. Minor impacts were found in the photochemical performance until 37 ºC, but extensive impacts were shown at 42 ºC, especially in IPR108. Remarkable was the finding that enhanced [CO2] preserved a higher functional status (Pn, Amax, Fo, Fv/Fm) at high temperatures (37 and 42 ºC), what seems quite relevant under the predicted climate changes and global warming scenarios.