Early inhibition of photosynthesis during development of Mn toxicity in tobacco. [Nicotiana tabacum L. cv KY14]

Journal Article · Fri Apr 01 04:00:00 EST 1988 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.86.4.1136· OSTI ID:6936497

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

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1. Univ. of Kentucky, Lexington (USA)

Early physiological effects of developing Mn toxicity in young leaves of burley tobacco (Nicotiana tabacum L. cv KY 14) were examined in glass-house/water cultured plants grown at high (summer) and low (winter) photon flux. Following transfer of plants to solutions containing 1 millimolar Mn{sup 2+}, sequential samplings were made at various times for the following 9 days, during which Mn accumulation by leaves increased rapidly from {approx} 70 on day 0 to {approx} 1700 and {approx} 5000 microgram per gram dry matter after 1 and 9 days, respectively. In plants grown at high photon flux, net photosynthesis declined by {approx} 20 and {approx} 60% after 1 and 9 days, respectively, and the onset of this decline preceded appearance (after 3 to 4 days) of visible foliar symptoms of Mn toxicity. Intercellular CO{sub 2} concentrations and rates of transpiration were not significantly affected. Though the activity of latent or activated polyphenol oxidase increased in parallel with Mn accumulation, neither leaf respiration nor the activity of catalase (EC 1.11.1.6) and peroxidase (EC 1.10.1.7) were greatly affected. These effects from Mn toxicity could not be explained by any changes in protein or chlorophyll abundance. Additionally, they were not a consequence of Mn induced Fe deficiency. Therefore, inhibition of net photosynthesis and enhancement of polyphenol oxidase activity are early indicators of excess Mn accumulation in tobacco leaves.

• OSTI ID: 6936497
• Journal Information: Plant Physiology; (USA), Journal Name: Plant Physiology; (USA) Vol. 86:4; ISSN PLPHA; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL ACCUMULATION
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CATALASE
CELL CONSTITUENTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHLOROPLASTS
ELEMENTS
ENZYME ACTIVITY
ENZYMES
INHIBITION
LEAVES
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MANGANESE
METALS
NICOTIANA
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PEROXIDASES
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
SEASONAL VARIATIONS
SYNTHESIS
TOXICITY
TRANSITION ELEMENTS
TRANSPIRATION
VARIATIONS