Production Ecophysiology of Hungarian Green Pepper Under Elevated Air CO2 Concentration

Production, dry matter (including reproductive) allocation, photosynthesis, transpiration, water use efficiency and carbon and nitrogen responses of a Hungarian sweet pepper (Capsicum annum L.) under continuous elevated CO2 concentrations are reported. Plants were grown in open top chambers under a temperate-continental climate in Hungary from plantation at ambient (350 mu mol mol(-1)) and elevated 700 mu mol mol(-1)) CO2 concentrations. The CO2 assimilation responses of the green pepper plants grown in high CO2 from plantation until final harvest reflected down-regulation of their photosynthesis. The integrated and combined effect of the increased net CO2 assimilation rate and the unchanged rate of transpiration resulted in higher WUE at elevated CO2 concentrations in the high CO2 plants than in the control ones grown at ambientCO(2). However, the improved water use efficiency in the high CO2 plants was not followed by an acclimation in C-translocation and C-allocation to the reproductive organs in the required degree. This was reflected in a slightly increased overall plant production and higher reproductive allocation, but was not accompanied by an increased fresh or dry berry mass production. The acclimation discussed may be of advantage for plant growth in a high CO2 environment with restricted water availability. We did not find worthy statistical difference between the yield mass of the control and elevated CO2, although the dry matter production parameters of the high CO2 plants had statistically not significantly higher values. (C) 2005 by The Haworth Press, Inc. All rights reserved.