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Elevated CO 2 and nitrogen availability have interactive effects on canopy carbon gain in rice
Author(s) -
Anten N. P. R.,
Hirose T.,
Onoda Y.,
Kinugasa T.,
Kim H. Y.,
Okada M.,
Kobayashi K.
Publication year - 2004
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2003.00943.x
Subject(s) - canopy , leaf area index , photosynthesis , nitrogen , oryza sativa , agronomy , carbon fibers , photosynthetic capacity , botany , chemistry , biology , mathematics , biochemistry , organic chemistry , algorithm , composite number , gene
Summary• Here we analysed the effects of CO 2 (C a ) elevation and nitrogen availability on canopy structure, leaf area index (LAI) and canopy photosynthesis of rice ( Oryza sativa ). • Rice was grown at ambient and elevated C a ( c. 200 µmol mol −1 above ambient, using the free‐air CO 2 enrichment, FACE) and at two N availabilities. We measured leaf area, area‐based leaf N contents and leaf photosynthesis, and calculated net daily canopy photosynthesis. • FACE plants had higher light‐saturated rates of photosynthesis ( P max ) and apparent quantum yields than ambient plants, when measured at their own growth CO 2 . C a elevation reduced the total leaf N in the canopy ( N leaf ) but had no effect on LAI, and the average leaf N content ( N leaf /LAI) was therefore reduced by 8%. This reduction corresponded well with our model predictions. Leaf area index increased strongly with N availability, which was also consistent with our model. • Calculated canopy photosynthesis increased more strongly with N leaf under elevated than under ambient C a . This indicates that there is an N × C a interactive effect on canopy carbon gain. This interaction was caused by the increase in LAI with N availability, which enhanced the positive effect of the higher quantum yield under C a elevation.