Sweet pepper acclimation to variable CO2 supply in a Mediterranean greenhouse

M.E. Porras, E. Medrano, P. Lorenzo, M.J. Sánchez-González, E.J. Baeza, M.C. Sánchez-Guerrero
Air CO2 enrichment improves the yield of greenhouse horticultural crops. The agricultural interest of this technique in Mediterranean climates was confirmed when CO2 supply was variable, maintaining high concentration when vents were closed and near the atmospheric level when vents were opened. In the long term, high CO2 ambient levels cause a reduction in photosynthetic capacity known as acclimation. This process reduces the efficiency of this technique. The supply of a fraction of NH4+ as nitrogen source in the nutrient solution can play an important role in maintaining the photosynthetic activity and could be interesting to delay the onset of this process. The aim of this study was to test whether acclimation occurred in sweet pepper plants when variable CO2 enrichment was applied in a Mediterranean greenhouse. The results showed a loss of the photosynthetic stimulation in plants at high CO2 concentrations after several weeks growing under this strategy. This acclimation process could be the cause of the reduction in the yield increase rate which was delayed with the ammonium supply.
Porras, M.E., Medrano, E., Lorenzo, P., Sánchez-González, M.J., Baeza, E.J. and Sánchez-Guerrero, M.C. 2017. Sweet pepper acclimation to variable CO2 supply in a Mediterranean greenhouse. Acta Hort. (ISHS) 1170:797-804
Capsicum annuum L., CO2 enrichment, photosynthesis, NH4+

Acta Horticulturae