Evidence for effects on the in vivo activity of ribulose-bisphosphate carboxylase/oxygenase during development of Mn toxicity in tobacco. [Nicotiana tabacum L. cv KY14]

Journal Article · Fri Apr 01 00:00:00 EST 1988 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.86.4.1143· OSTI ID:7189438

Houtz, R L; Nable, R O; Cheniae, G M ^[1]

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1. Univ. of Kentucky, Lexington (USA)

The progressive decrease in net photosynthesis accompanying development of Mn toxicity in young leaves of burley tobacco (Nicotiana tabacum L. cv KY 14) is a result of effects on in vivo activity of ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (rubisco, EC 4.1.1.39). This conclusion is supported by: (a) decrease in rates of CO{sub 2} depletion during measurements of CO{sub 2} compensation, (b) increase in leaf RuBP concentrations, (c) progressive decreases in rate-constants of RuBP loss (light to dark transition analyses) with progressive increases of leaf Mn concentrations, and (d) restoration of diminished rates of net photosynthesis to control rates by elevated CO{sub 2} (5%). Moreover, elevated CO{sub 2} (1100 microliters per liter) during culture of Mn-treated plants decreased elevated RuBP concentrations to control levels and alleviated foliar symptoms of Mn toxicity. These effects of Mn toxicity on in vivo activity of rubisco were not expressed by in vitro kinetic analyses of rubisco prepared under conditions to sequester Mn or to adsorb polyphenols or their oxidation products. Similarly, the in vitro activity of fructose bisphosphatase (EC 3.1.3.11) was unaffected by Mn toxicity.

• OSTI ID: 7189438
• Journal Information: Plant Physiology; (USA), Vol. 86:4; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
MANGANESE
TOXICITY
NICOTIANA
PHOTOSYNTHESIS
RIBULOSE DIPHOSPHATE CARBOXYLASE
ENZYME ACTIVITY
BIOCHEMICAL REACTION KINETICS
CARBON DIOXIDE
IN VITRO
IN VIVO
LEAVES
PHOSPHATASES
CARBON COMPOUNDS
CARBON OXIDES
CARBON-CARBON LYASES
CARBOXY-LYASES
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
ENZYMES
ESTERASES
HYDROLASES
KINETICS
LYASES
MAGNOLIOPHYTA
MAGNOLIOPSIDA
METALS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
REACTION KINETICS
SYNTHESIS
TRANSITION ELEMENTS
560300* - Chemicals Metabolism & Toxicology