title: Does low stomatal conductance or photosynthetic capacity enhance growth at elevated CO2 in Arabidopsis?
abstract: The objective of this study was to determine if low stomatal conductance (g) increases growth, nitrate (NO3 (-)) assimilation, and nitrogen (N) utilization at elevated CO2 concentration. Four Arabidopsis (Arabidopsis thaliana) near isogenic lines (NILs) differing in g were grown at ambient and elevated CO2 concentration under low and high NO3 (-) supply as the sole source of N. Although g varied by 32% among NILs at elevated CO2, leaf intercellular CO2 concentration varied by only 4% and genotype had no effect on shoot NO3 (-) concentration in any treatment. Low-g NILs showed the greatest CO2 growth increase under N limitation but had the lowest CO2 growth enhancement under N-sufficient conditions. NILs with the highest and lowest g had similar rates of shoot NO3 (-) assimilation following N deprivation at elevated CO2 concentration. After 5 d of N deprivation, the lowest g NIL had 27% lower maximum carboxylation rate and 23% lower photosynthetic electron transport compared with the highest g NIL. These results suggest that increased growth of low-g NILs under N limitation most likely resulted from more conservative N investment in photosynthetic biochemistry rather than from low g.
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616 (H.M.E., E.C., A.J.B.); andDepartment of Bioagricultural Sciences, Colorado State University, Fort Collins, Colorado 80523 (J.K.M.) heaslon@ucdavis.edu.
authors.forename: Hsien Ming
authors.initials: HM
authors.lastname: Easlon
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616 (H.M.E., E.C., A.J.B.); andDepartment of Bioagricultural Sciences, Colorado State University, Fort Collins, Colorado 80523 (J.K.M.).
authors.forename: Eli
authors.initials: E
authors.lastname: Carlisle
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616 (H.M.E., E.C., A.J.B.); andDepartment of Bioagricultural Sciences, Colorado State University, Fort Collins, Colorado 80523 (J.K.M.).
authors.forename: John K
authors.initials: JK
authors.lastname: McKay
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616 (H.M.E., E.C., A.J.B.); andDepartment of Bioagricultural Sciences, Colorado State University, Fort Collins, Colorado 80523 (J.K.M.).
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: Bloom
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology*; D018533:Biomass; D002245:Carbon Dioxide / Q000494:pharmacology*; D002247:Carbon Isotopes; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D054046:Plant Stomata / Q000187:drug effects / Q000502:physiology*
chemical_list: D002247:Carbon Isotopes; D009566:Nitrates; D002245:Carbon Dioxide; D009584:Nitrogen