Abstract
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(2) depletion during measurements of CO(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(2) (5%). Moreover, elevated CO(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.
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Claims 10
Claim · model-written summary
Mn toxicity progressively decreased net photosynthesis in young tobacco leaves.
- Taxon
- burley tobaccoe0
- Material
- Nicotiana tabacum L. cv KY 14e0
- Organ / stage
- young leavese0
- Treatment
- Mn toxicitye0
- Outcome
- net photosynthesise0
- Direction
- decreasee0
Not reportedComparator
Verbatim
e0“The progressive decrease in net photosynthesis accompanying development of Mn toxicity in young leaves of burley tobacco (Nicotiana tabacum L. cv KY 14)”
Claim · model-written summary
Mn toxicity reduced in vivo rubisco activity, accounting for decreased net photosynthesis.
- Taxon
- Tobacco
Nicotiana tabacumt0 - Gene
- ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenasee0
- Outcome
- in vivo activitye0
- Qualifier
- effects on in vivo activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“is a result of effects on in vivo activity of ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (rubisco, EC 4.1.1.39).”
t0“Mn Toxicity in Tobacco”
Claim · model-written summary
Rates of CO2 depletion decreased during CO2 compensation measurements.
- Taxon
- TobaccoNicotiana tabacumt0
- Outcome
- rates of CO(2) depletione0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decrease in rates of CO(2) depletion during measurements of CO(2) compensation”
t0“Tobacco”
Claim · model-written summary
Leaf RuBP concentrations increased with Mn toxicity.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- Mn Toxicityt0
- Outcome
- leaf RuBP concentrationse0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increase in leaf RuBP concentrations”
t0“Mn Toxicity in Tobacco”
Claim · model-written summary
RuBP loss rate constants progressively decreased as leaf Mn concentration increased.
- Taxon
- TobaccoNicotiana tabacumt0
- Organ / stage
- leafe0
- Compound
- Mne0
- Outcome
- rate-constants of RuBP losse0
- Direction
- decreasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“progressive decreases in rate-constants of RuBP loss (light to dark transition analyses) with progressive increases of leaf Mn concentrations”
t0“Tobacco”
Claim · model-written summary
Elevated CO2 at 5% restored diminished net photosynthesis to control rates.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- elevated CO(2) (5%)e0
- Outcome
- net photosynthesise0
- Direction
- restoratione0
- Comparator
- control ratese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“restoration of diminished rates of net photosynthesis to control rates by elevated CO(2) (5%)”
t0“Tobacco”
Claim · model-written summary
Elevated CO2 at 1100 microliters per liter decreased RuBP concentrations in Mn-treated plants to control levels.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- elevated CO(2) (1100 microliters per liter)e0
- Outcome
- RuBP concentrationse0
- Direction
- decreasede0
- Comparator
- control levelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“elevated CO(2) (1100 microliters per liter) during culture of Mn-treated plants decreased elevated RuBP concentrations to control levels”
t0“Tobacco”
Claim · model-written summary
Elevated CO2 at 1100 microliters per liter alleviated foliar symptoms of Mn toxicity.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- elevated CO(2) (1100 microliters per liter)e0
- Outcome
- foliar symptoms of Mn toxicitye0
- Direction
- alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“elevated CO(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.”
t0“Tobacco”
Claim · model-written summary
In vitro rubisco kinetic analyses did not express the Mn toxicity effect seen in vivo.
- Taxon
- TobaccoNicotiana tabacumt0
- Gene
- rubiscoe0
- Outcome
- effects of Mn toxicity on in vivo activity of rubiscoe0
- Direction
- not expressede0
- Qualifier
- in vitro kinetic analysese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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.”
t0“Tobacco”
Claim · model-written summary
In vitro fructose bisphosphatase activity was unaffected by Mn toxicity.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- Mn toxicitye0
- Gene
- fructose bisphosphatasee0
- Outcome
- in vitro activity of fructose bisphosphatasee0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the in vitro activity of fructose bisphosphatase (EC 3.1.3.11) was unaffected by Mn toxicity.”
t0“Tobacco”
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12 papers more in this group
See all 16 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.