Elevated Atmospheric CO2 Improved Sorghum Plant Water Status by Ameliorating the Adverse Effects of Drought

• Published in: The New phytologist Vol. 152; no. 2; pp. 231 - 248
• Main Authors: Wall, G. W., Brooks, T. J., Adam, N. R., Cousins, A. B., Kimball, B. A., Pinter, P. J., LaMorte, R. L., Triggs, J., Ottman, M. J., Leavitt, S. W., Matthias, A. D., Williams, D. G., Webber, A. N.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science 01-11-2001; Blackwell Science Ltd; Blackwell
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Atmospherics; Biological and medical sciences; Carbon dioxide; Climatic adaptation. Acclimatization; Dehydration; Drought; Evapotranspiration; free‐air CO2 enrichment (FACE); Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; global change; Irrigation; net assimilation rate; Plants; Sorghum; stomatal conductance; Transpiration; Water consumption; water relations; Monocotyledones; Interaction; Carbon dioxide; Stomatal conductance; Environmental factor; Water potential; Water stress; Cereal crop; Medium enrichment; Improvement; Sorghum bicolor; Gramineae; Water regime; Net assimilation rate; Drought resistance; Angiospermae; Water content; Spermatophyta; Climate modification; Adaptation
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1046/j.0028-646x.2001.00260.x

• The interactive effects of atmospheric CO2 concentration and soil-water content on grain sorghum (Sorghum bicolor) are reported here. • Sorghum plants were exposed to ambient (control) and free-air CO2 enrichment (FACE; ambient+200 μ mol mol-1), under ample (wet, 100% replacement of evapotranspiration) and reduced (dry, postplanting and mid-season irrigations) water supply over two growing seasons. • FACE reduced seasonal average stomatal conductance (g s) by 0.17 mol ( H2 O) m-2 s-1 (32% and 37% for dry and wet, respectively) compared with control; this was similar to the difference between dry and wet treatments. FACE increased net assimilation rate (A) by 4.77 μmol ( CO2) m-2 s-1 (23% and 9% for dry and wet, respectively), whereas dry decreased A by 10.50 μmol ( CO2) m-2 s-1 (26%) compared with wet. Total plant water potential (Ψ w) was 0.16 MPa (9%) and 0.04 MPa (3%) less negative in FACE than in the control treatment for dry and wet, respectively. Under dry, FACE stimulated final shoot biomass by 15%. • By ameliorating the adverse effects of drought, elevated atmospheric CO2 improved plant water status, which indirectly caused an increase in carbon gain.