Leaf injury to bean plants grown in carbon dioxide enriched atmospheres

Bush bean (Phaseolus vulgaris L.) plants grown in atmospheres enriched with CO 2 (1400 μL L −1 ) showed marked reductions in photosynthetic capacity and accelerated chlorosis of primary leaves. Leaf injury was observed only in CO 2 -enriched plants, but the degree of injury was regulated by secondary factors, light and temperature. Conditions of relatively high light intensity (340–370 μmol m −2 s −1 photosynthetic photon flux density) or cool temperature (20 °C) promoted leaf injury of CO 2 -enriched plants. Leaf starch accumulation was highest under conditions that caused injury. The enhanced chlorosis and corresponding decline in photosynthetic activity, however, were not related to changes in stomatal diffusive resistance or leaf water status. Contaminant gases, such as ethylene, were not detectable in the CO 2 -enrichment chambers.