Oxygen and carbon dioxide fluxes from barley shoots depend on nitrate assimilation

A custom oxygen analyzer in conjunction with an infrared carbon dioxide analyzer and humidity sensors permitted simultaneous measurements of oxygen, carbon dioxide, and water vapor fluxes from the shoots of intact barley plants (Hordeum vulgare L. cv Steptoe). The oxygen analyzer is based on a calci...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1989-09, Vol.91 (1), p.352-356
Main Authors: Bloom, A.J. (University of California, Davis, CA), Caldwell, R.M, Finazzo, J, Warner, R.L, Weissbart, J
Format: Article
Language:English
Subjects:
AGUA
ASIMILACION
ASSIMILATION
Barley
Biological and medical sciences
Carbon dioxide
DEBIT
DIOXIDO DE CARBONO
DIOXYDE DE CARBONE
EAU
FOTOSINTESIS
Fundamental and applied biological sciences. Psychology
GASTO
HORDEUM VULGARE
INSTRUMENT
INSTRUMENTOS
MEDICION
MESURE
Metabolism
MITOCHONDRIE
MITOCONDRIA
NITRATE
Nitrates
NITRATOS
Nitrogen
OXIGENO
Oxygen
OXYGENE
PHOTOSYNTHESE
Photosynthesis
Photosynthesis, respiration. Anabolism, catabolism
Physiological assimilation
Plant physiology and development
Plant roots
Plants
RESPIRACION
RESPIRATION
TALLO
TIGE
TRANSPORT DES SUBSTANCES NUTRITIVES
TRANSPORTE DE NUTRIENTES
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Description
Summary:A custom oxygen analyzer in conjunction with an infrared carbon dioxide analyzer and humidity sensors permitted simultaneous measurements of oxygen, carbon dioxide, and water vapor fluxes from the shoots of intact barley plants (Hordeum vulgare L. cv Steptoe). The oxygen analyzer is based on a calciazirconium sensor and can resolve concentration differences to within 2 microliters per liter against the normal background of 210,000 microliters per liter. In wild-type plants receiving ammonium as their sole nitrogen source or in nitrate reductase-deficient mutants, photosynthetic and respiratory fluxes of oxygen equaled those of carbon dioxide. By contrast, wild-type plants exposed to nitrate had unequal oxygen and carbon dioxide fluxes: oxygen evolution at high light exceeded carbon dioxide consumption by 26% and carbon dioxide evolution in the dark exceeded oxygen consumption by 25%. These results indicate that a substantial portion of photosynthetic electron transport or respiration generates reductant for nitrate assimilation rather than for carbon fixation or mitochondrial electron transport
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.91.1.352