Elevated carbon dioxide and water stress effects on potato canopy gas exchange, water use, and productivity.
Authors:
Fleisher, David H. Timlin, Dennis J. Reddy, V.R. USDA, ARS
Source:
Agricultural and forest meteorology. 2008 June 30, v. 148, no. 6-7 [Oxford]: Elsevier Science Ltd., p. 1109-1122.
NALT Subjects:
Solanum tuberosum potatoes canopy carbon dioxide elevated atmospheric gases plant response soil-plant-atmosphere interactions water stress gas exchange diurnal variation seasonal variation growing season water use efficiency dry matter accumulation irrigation rates net assimilation rate radiation use efficiency water uptake climate change drought
Other Subjects:
controlled atmosphere chambers
Issue Date:
30-Jun-2008
Abstract:
Despite the agronomic importance of potato (Solanum tuberosum L.), the interaction of atmospheric carbon dioxide concentration ([CO₂]) and drought has not been well studied. Two soil-plant-atmosphere research (SPAR) chamber experiments were conducted concurrently at ambient (370μmolmol⁻¹) and elevated (740μmolmol⁻¹) [CO₂]. Daily irrigation for each chamber was applied according to a fixed percentage of the water uptake measured for a control chamber for each [CO₂] treatment. We monitored diurnal and seasonal canopy photosynthetic (A G) and transpiration rates and organ dry weights at harvest. Plants grown under elevated [CO₂] had consistently larger photosynthetic rates through most of the growth season, with the maximum A G at 1600μmolphotonsm⁻² s⁻¹ 14% higher at the well-watered treatments. Water stress influenced ambient [CO₂] plants to a larger extent, and reduced maximum canopy A G, growth season duration, and seasonal net carbon assimilation up to 50% of the control in both [CO₂] treatments. Water use efficiency increased with water stress, particularly at elevated [CO₂], ranging from 4.9 to 9.3gdrymassL⁻¹. Larger photosynthetic rates for elevated [CO₂] resulted in higher seasonal dry mass and radiation use efficiency (RUE) as compared with ambient [CO₂] at the same irrigation level. This extra assimilate was partitioned to underground organs, resulting in higher harvest indices. Our findings indicate that increases in potato growth and productivity with elevated [CO₂] are consistent over most levels of water stress. This work can support various climate change scenarios that evaluate different management practices with potato.
