Abstract
Abstract Symptoms of Mn toxicity in tobacco ( Nicotiana tabacum L.) are often observed in the mountain region of North Carolina at soil acidity and soil test levels of Mn which do not produce toxicity in the piedmont. Although genotypic differences between tobacco types grown in the regions may contribute to the differential response, variations in temperature between the regions may also be involved. To investigate the effects of temperature on plant growth and Mn tolerance, tobacco plants of a prevalent cultivar (‘Coker 347’) for the piedmont region were grown in sand culture at day/night temperatures of 22/18, 26/22, and 30/26 C. Manganese was applied daily at rates of 10, 20, 40, 80, and 120 mg/liter in a complete nutrient solution. Plants were sampled weekly during a 6‐week growth period and evaluated for visual toxicity symptoms, dry weight. Mn concentration, relative growth rate (RGR), and relative accumulation rate (RAR) of Mn. Plant tolerance to high rates of applied Mn increased with increasing temperature despite significantly greater tissue concentrations of Mn during early growth. Tissue levels of Mn in leaves associated with the appearance of visual toxicity symptoms were 700 to 1,200 mg/kg dry wt at 22/18 C, 2,000 to 3,500 mg/kg at 26/22 C, and 5,000 to 8,000 mg/kg at 30/26 C. Mn toxicity symptoms were more severe in immature leaves and often decreased as the leaves matured even though the concentration of Mn in the leaves increased. The RGR of leaves during the exponential growth phase increased with increasing temperatures at each Mn rate, but the RAR of Mn was unaffected by either temperature or applied Mn rate. It is proposed that the increased tolerance to high levels of tissue Mn by plants grown in warm temperatures is associated with more rapid rates of leaf expansion accompanied by increased vaculor capacity for disposal of accumulated Mn.
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Claims 11
Claim · model-written summary
Tobacco tolerance of high applied manganese increased with temperature.
- Taxon
- Tobacco
Nicotiana tabacumt0 - Treatment
- increasing temperaturee0
- Outcome
- Plant tolerance to high rates of applied Mne0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant tolerance to high rates of applied Mn increased with increasing temperature despite significantly greater tissue concentrations of Mn during early growth.”
t0“Tobacco”
Claim · model-written summary
Higher temperature produced significantly greater early-growth tissue manganese concentrations.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- increasing temperaturee0
- Outcome
- tissue concentrations of Mne0
- Direction
- greatere0
- Qualifier
- during early growthe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plant tolerance to high rates of applied Mn increased with increasing temperature despite significantly greater tissue concentrations of Mn during early growth.”
t0“Tobacco”
Claim · model-written summary
At 22/18 C, leaf manganese levels associated with visible toxicity were 700 to 1,200 mg/kg dry wt.
- Taxon
- TobaccoNicotiana tabacumt0
- Organ / stage
- leavese0
- Treatment
- 22/18 Ce0
- Outcome
- Tissue levels of Mne0
- Value
- 700 to 1,200 mg/kg dry wte0
- Qualifier
- associated with the appearance of visual toxicity symptomse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Tissue levels of Mn in leaves associated with the appearance of visual toxicity symptoms were 700 to 1,200 mg/kg dry wt at 22/18 C, 2,000 to 3,500 mg/kg at 26/22 C, and 5,000 to 8,000 mg/kg at 30/26 C.”
t0“Tobacco”
Claim · model-written summary
At 26/22 C, leaf manganese levels associated with visible toxicity were 2,000 to 3,500 mg/kg.
- Taxon
- TobaccoNicotiana tabacumt0
- Organ / stage
- leavese0
- Treatment
- 26/22 Ce0
- Outcome
- Tissue levels of Mne0
- Value
- 2,000 to 3,500 mg/kge0
- Qualifier
- associated with the appearance of visual toxicity symptomse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Tissue levels of Mn in leaves associated with the appearance of visual toxicity symptoms were 700 to 1,200 mg/kg dry wt at 22/18 C, 2,000 to 3,500 mg/kg at 26/22 C, and 5,000 to 8,000 mg/kg at 30/26 C.”
t0“Tobacco”
Claim · model-written summary
At 30/26 C, leaf manganese levels associated with visible toxicity were 5,000 to 8,000 mg/kg.
- Taxon
- TobaccoNicotiana tabacumt0
- Organ / stage
- leavese0
- Treatment
- 30/26 Ce0
- Outcome
- Tissue levels of Mne0
- Value
- 5,000 to 8,000 mg/kge0
- Qualifier
- associated with the appearance of visual toxicity symptomse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Tissue levels of Mn in leaves associated with the appearance of visual toxicity symptoms were 700 to 1,200 mg/kg dry wt at 22/18 C, 2,000 to 3,500 mg/kg at 26/22 C, and 5,000 to 8,000 mg/kg at 30/26 C.”
t0“Tobacco”
Claim · model-written summary
Manganese toxicity symptoms were more severe in immature leaves and often decreased during maturation.
- Taxon
- TobaccoNicotiana tabacumt0
- Organ / stage
- immature leavese0
- Outcome
- Mn toxicity symptomse0
- Direction
- more severee0
- Qualifier
- often decreased as the leaves maturede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mn toxicity symptoms were more severe in immature leaves and often decreased as the leaves matured even though the concentration of Mn in the leaves increased.”
t0“Tobacco”
Claim · model-written summary
Leaf manganese concentration increased as leaves matured.
- Taxon
- TobaccoNicotiana tabacumt0
- Organ / stage
- leavese0
- Outcome
- concentration of Mn in the leavese0
- Direction
- increasede0
- Qualifier
- as the leaves maturede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mn toxicity symptoms were more severe in immature leaves and often decreased as the leaves matured even though the concentration of Mn in the leaves increased.”
t0“Tobacco”
Claim · model-written summary
Leaf relative growth rate increased with temperature during exponential growth at each manganese rate.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- increasing temperaturese0
- Outcome
- RGR of leavese0
- Direction
- increasede0
- Qualifier
- during the exponential growth phasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The RGR of leaves during the exponential growth phase increased with increasing temperatures at each Mn rate, but the RAR of Mn was unaffected by either temperature or applied Mn rate.”
t0“Tobacco”
Claim · model-written summary
Temperature did not affect manganese relative accumulation rate.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- temperaturee0
- Outcome
- RAR of Mne0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the RAR of Mn was unaffected by either temperature or applied Mn rate.”
t0“Tobacco”
Claim · model-written summary
Applied manganese rate did not affect manganese relative accumulation rate.
- Taxon
- TobaccoNicotiana tabacumt0
- Treatment
- applied Mn ratee0
- Outcome
- RAR of Mne0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the RAR of Mn was unaffected by either temperature or applied Mn rate.”
t0“Tobacco”
Claim · model-written summary
The authors propose that faster leaf expansion and greater vacuolar disposal capacity explain warm-temperature manganese tolerance.
- Taxon
- TobaccoNicotiana tabacumt0
- Outcome
- tolerance to high levels of tissue Mne0
- Direction
- increasede0
- Qualifier
- more rapid rates of leaf expansion accompanied by increased vaculor capacity for disposal of accumulated Mne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It is proposed that the increased tolerance to high levels of tissue Mn by plants grown in warm temperatures is associated with more rapid rates of leaf expansion accompanied by increased vaculor capacity for disposal of accumulated Mn.”
t0“Tobacco”
The same questions in other papers
manganese atom · molecular: metabolites · Nicotiana tabacum (tobacco)Positive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
- negative
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.