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Rice Photosynthesis and Evapotranspiration in Subambient, Ambient, and Superambient Carbon Dioxide Concentrations
Author(s) -
Baker J. T.,
Allen L. H.,
Boote K. J.,
Jones P.,
Jones J. W.
Publication year - 1990
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1990.00021962008200040034x
Subject(s) - photosynthesis , carbon dioxide , oryza sativa , evapotranspiration , stomatal conductance , water use efficiency , canopy , transpiration , cultivar , carbon dioxide in earth's atmosphere , agronomy , chemistry , horticulture , zoology , botany , environmental science , biology , ecology , biochemistry , organic chemistry , gene
The current global rise in atmospheric carbon dioxide concentration, [CO 2 ], has stimulated interest in the response of agricultural crops to [CO 2 ]. The objectives were to determine the effects of [CO 2 ] on photosynthesis, evapotranspiration, and water use efficiency of rice ( Oryza sativa , L., cv. IR‐30). Rice plants were grown in naturally sunlit, plant growth chambers in subambient (160 and 250), ambient (330), or superambient (500, 660, and 900 μ mol CO 2 mol −1 air) [CO 2 ] treatments. Photosynthetic light response curves were analyzed to obtain estimates of canopy light utilization efficiency ( α ) and canopy conductance to CO 2 transfer ( τ ). Estimates of ℵ increased with increasing [CO 2 ] treatment with the greatest increase in the 160 ito 500 μ mol mol −1 treatments. Estimates of were more variable tham those for τ and were not different among [CO 2 ] treatments. Photosynthetic rates increased with increasing [CO 2 ] treatment from 160 to 500 μmol mol −1 followed by a leveling off of the response among the superambient [CO 2 ] treatments. Evapotranspiration decreased while water‐use efficiency increased with increasing [CO 2 ]. Shortterm cross‐switching of [CO 2 ] among the chambers revealed a profound adaptive response to long‐term [CO 2 ] growth treatments. Photosynthetic rate, measured at a common [CO 2 ], decreased with increasing long‐term [CO 2 ] growth treatment. The lack of further Photosynthetic response above the 500 μmol mol −1 [CO 2 ] treatment appears to indicate a need to select or screen rice cultivars for increased response to superambient [CO 2 ] in order to more fully take advantage of future increases in global atmospheric [CO 2 ].