Five-year-old plants of two olive cultivars (Frantoio and Moraiolo) grown in large pots were exposed for 7 to 8 months to ambient (AC) or elevated (EC) CO2 concentration in a free-air CO2 enrichment (FACE) facility. Exposure to EC enhanced net photosynthetic rate (P-N) and decreased stomatal conductance, leading to greater instantaneous transpiration efficiency. Stomata density also decreased under EC, while the ratio of intercellular (C-i) to atmospheric CO2 concentration and chlorophyll content did not differ, except for the cv. Moraiolo after seven months of exposure to EC. Analysis of the relationship between photosynthesis and C-i indicated no significant change in carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxygenase after five months of exposure to EC. Based on estimates derived from the P-N-C-i relationship, there were no apparent treatment differences in daytime respiration, CO2 compensation concentration, CO2-saturated photosynthetic rate, or photosynthetic rate at the mean C-i, but there was a reduction in stomata limitation to P-N at EC. Thus 5-year-old olive trees did not exhibit down regulation of leaf-level photosynthesis in their response to EC, though some indication of adjustment was evident for the cv. Frantoio with respect to the cv. Moraiolo.
Responses of two olive tree (Olea europaea L.) cultivars to elevated CO2 concentration in the field
Raschi A;
2001
Abstract
Five-year-old plants of two olive cultivars (Frantoio and Moraiolo) grown in large pots were exposed for 7 to 8 months to ambient (AC) or elevated (EC) CO2 concentration in a free-air CO2 enrichment (FACE) facility. Exposure to EC enhanced net photosynthetic rate (P-N) and decreased stomatal conductance, leading to greater instantaneous transpiration efficiency. Stomata density also decreased under EC, while the ratio of intercellular (C-i) to atmospheric CO2 concentration and chlorophyll content did not differ, except for the cv. Moraiolo after seven months of exposure to EC. Analysis of the relationship between photosynthesis and C-i indicated no significant change in carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxygenase after five months of exposure to EC. Based on estimates derived from the P-N-C-i relationship, there were no apparent treatment differences in daytime respiration, CO2 compensation concentration, CO2-saturated photosynthetic rate, or photosynthetic rate at the mean C-i, but there was a reduction in stomata limitation to P-N at EC. Thus 5-year-old olive trees did not exhibit down regulation of leaf-level photosynthesis in their response to EC, though some indication of adjustment was evident for the cv. Frantoio with respect to the cv. Moraiolo.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
