Premium
Nitrogen balance for wheat canopies ( Triticum aestivum cv. Veery 10) grown under elevated and ambient CO 2 concentrations
Author(s) -
Smart D. R.,
Ritchie K.,
Bloom A. J.,
Bugbee B. B.
Publication year - 1998
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.1365-3040.1998.00315.x
Subject(s) - nitrogen , chemistry , nitrate , nitrogen balance , biomass (ecology) , horticulture , zoology , agronomy , biology , organic chemistry
We examined the hypothesis that elevated CO 2 concentration would increase NO 3 – absorption and assimilation using intact wheat canopies ( Triticum aestivum cv. Veery 10). Nitrate consumption, the sum of plant absorption and nitrogen loss, was continuously monitored for 23 d following germination under two CO 2 concentrations (360 and 1000 μ mol mol –1 CO 2 ) and two root zone NO 3 – concentrations (100 and 1000 mmol m 3 NO 3 – ). The plants were grown at high density (1780 m –2 ) in a 28 m 3 controlled environment chamber using solution culture techniques. Wheat responded to 1000 μ mol mol –1 CO 2 by increasing carbon allocation to root biomass production. Elevated CO 2 also increased root zone NO 3 – consumption, but most of this increase did not result in higher biomass nitrogen. Rather, nitrogen loss accounted for the greatest part of the difference in NO 3 – consumption between the elevated and ambient [CO 2 ] treatments. The total amount of NO 3 – ‐N absorbed by roots or the amount of NO 3 – ‐N assimilated per unit area did not significantly differ between elevated and ambient [CO 2 ] treatments. Instead, specific leaf organic nitrogen content declined, and NO 3 – accumulated in canopies growing under 1000 μ mol mol –1 CO 2 . Our results indicated that 1000 μ mol mol –1 CO 2 diminished NO 3 – assimilation. If NO 3 – assimilation were impaired by high [CO 2 ], then this offers an explanation for why organic nitrogen contents are often observed to decline in elevated [CO 2 ] environments.