ISHS Acta Horticulturae 449: II International Symposium on Irrigation of Horticultural Crops
WATER USE EFFICIENCY IN PHASEOLUS VULGARIS EXPOSED TO ELEVATED CO2 |
| Authors: | J.M. Mjwara, C.E.J. Botha |
| Keywords: | Carbon isotope discrimination, elevated CO2, Phaseolus vulgaris, stomatal conductance, transpiration, water use efficiency |
| Abstract:
Stomatal conductance (gs) declined significantly as expected in bean plants grown under elevated CO2-. Similarly a significant decline in transpiration rates (E) occurred in these plants. Reduced gs and E led to high net carbon assimilation (A)l E ratio which meant improved water use efficiency (WUE) values for CO2-enriched bean plants. Leaf carbon isotope discrimination (Δ) against heavier isotope of carbon (13C) has been used increasingly to select for high WUE in C3 plants. Δ was significantly reduced in plants grown under elevated CO2. Although Δ was negatively correlated to WUE in both CO2 treatments, the correlation was steeper and highly negative for CO2-enriched plants. These results indicate underlying differences in gas exchange physiology including stomatal responses that directly affect water economy in ambient and elevated CO2-grown plants. | |
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