Abstract
Exposure of the leaf canopy of corn seedlings (Zea mays L.) to atmospheric CO(2) levels ranging from 100 to 800 mul/l decreased nitrate accumulation and nitrate reductase activity. Plants pretreated with CO(2) in the dark and maintained in an atmosphere containing 100 mul/l CO(2) accumulated 7-fold more nitrate and had 2-fold more nitrate reductase activity than plants exposed to 600 mul/l CO(2), after 5 hours of illumination. Induction of nitrate reductase activity in leaves of intact corn seedlings was related to nitrate content. Changes in soluble protein were related to in vitro nitrate reductase activity suggesting that in vitro nitrate reductase activity was a measure of in situ nitrate reduction. In longer experiments, levels of nitrate reductase and accumulation of reduced N supported the concept that less nitrate was being absorbed, translocated, and assimilated when CO(2) was high. Plants exposed to increasing CO(2) levels for 3 to 4 hours in the light had increased concentrations of malate and decreased concentrations of nitrate in the leaf tissue. Malate and nitrate concentrations in the leaf tissue of seven of eight corn genotypes grown under comparable and normal (300 mul/l CO(2)) environments, were negatively correlated. Exposure of roots to increasing concentrations of potassium carbonate with or without potassium sulfate caused a progressive increase in malate concentrations in the roots. When these roots were subsequently transferred to a nitrate medium, the accumulation of nitrate was inversely related to the initial malate concentrations. These data suggest that the concentration of malate in the tissue seem to be related to the accumulation of nitrate.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 12
Claim · model-written summary
Higher atmospheric CO(2) decreased nitrate accumulation in corn seedlings.
- Taxon
- corn seedlings
Zea mays subsp. mayse0 - Treatment
- atmospheric CO(2) levels ranging from 100 to 800 mul/le0
- Outcome
- nitrate accumulatione0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exposure of the leaf canopy of corn seedlings (Zea mays L.) to atmospheric CO(2) levels ranging from 100 to 800 mul/l decreased nitrate accumulation and nitrate reductase activity”
Claim · model-written summary
Higher atmospheric CO(2) decreased nitrate reductase activity in corn seedlings.
- Taxon
- corn seedlingsZea mays subsp. mayse0
- Treatment
- atmospheric CO(2) levels ranging from 100 to 800 mul/le0
- Gene
- nitrate reductasee0
- Outcome
- nitrate reductase activitye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exposure of the leaf canopy of corn seedlings (Zea mays L.) to atmospheric CO(2) levels ranging from 100 to 800 mul/l decreased nitrate accumulation and nitrate reductase activity”
Claim · model-written summary
After five hours of illumination, 100 mul/l CO(2) yielded sevenfold more nitrate accumulation than 600 mul/l CO(2).
- Taxon
- corn seedlingsZea mays subsp. mayse1
- Treatment
- 100 mul/l CO(2)e0
- Outcome
- nitratee0
- Direction
- moree0
- Value
- 7-folde0
- Qualifier
- after 5 hours of illuminatione0
- Comparator
- 600 mul/l CO(2)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants pretreated with CO(2) in the dark and maintained in an atmosphere containing 100 mul/l CO(2) accumulated 7-fold more nitrate and had 2-fold more nitrate reductase activity than plants exposed to 600 mul/l CO(2), after 5 hours of illumination”
e1“corn seedlings (Zea mays L.)”
Claim · model-written summary
After five hours of illumination, 100 mul/l CO(2) yielded twofold more nitrate reductase activity than 600 mul/l CO(2).
- Taxon
- corn seedlingsZea mays subsp. mayse1
- Treatment
- 100 mul/l CO(2)e0
- Outcome
- nitrate reductase activitye0
- Direction
- moree0
- Value
- 2-folde0
- Comparator
- 600 mul/l CO(2)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants pretreated with CO(2) in the dark and maintained in an atmosphere containing 100 mul/l CO(2) accumulated 7-fold more nitrate and had 2-fold more nitrate reductase activity than plants exposed to 600 mul/l CO(2), after 5 hours of illumination”
e1“corn seedlings (Zea mays L.)”
Claim · model-written summary
Nitrate reductase induction in corn leaves was related to nitrate content.
- Taxon
- corn seedlingsZea mays subsp. mayse0
- Organ / stage
- leavese0
- Compound
- nitratee0
- Outcome
- Induction of nitrate reductase activitye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Induction of nitrate reductase activity in leaves of intact corn seedlings was related to nitrate content”
Claim · model-written summary
Soluble protein changes were related to in vitro nitrate reductase activity.
- Taxon
- corn seedlingsZea mays subsp. mayse1
- Gene
- soluble proteine0
- Outcome
- in vitro nitrate reductase activitye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Changes in soluble protein were related to in vitro nitrate reductase activity”
e1“corn seedlings (Zea mays L.)”
Claim · model-written summary
Higher CO(2) was associated with less nitrate absorption, translocation, and assimilation in longer experiments.
- Taxon
- corn seedlingsZea mays subsp. mayse1
- Treatment
- CO(2) was highe0
- Outcome
- nitrate was being absorbed, translocated, and assimilatede0
- Direction
- lesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“less nitrate was being absorbed, translocated, and assimilated when CO(2) was high”
e1“corn seedlings (Zea mays L.)”
Claim · model-written summary
Increasing CO(2) increased leaf malate concentration in corn.
- Taxon
- corn seedlingsZea mays subsp. mayse1
- Organ / stage
- leaf tissuee0
- Treatment
- increasing CO(2) levelse0
- Outcome
- concentrations of malatee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants exposed to increasing CO(2) levels for 3 to 4 hours in the light had increased concentrations of malate and decreased concentrations of nitrate in the leaf tissue”
e1“corn seedlings (Zea mays L.)”
Claim · model-written summary
Increasing CO(2) decreased leaf nitrate concentration in corn.
- Taxon
- corn seedlingsZea mays subsp. mayse1
- Organ / stage
- leaf tissuee0
- Treatment
- increasing CO(2) levelse0
- Outcome
- concentrations of nitratee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants exposed to increasing CO(2) levels for 3 to 4 hours in the light had increased concentrations of malate and decreased concentrations of nitrate in the leaf tissue”
e1“corn seedlings (Zea mays L.)”
Claim · model-written summary
Leaf malate and nitrate concentrations were negatively correlated in seven of eight corn genotypes.
- Taxon
- cornZea mays subsp. mayse0
- Material
- corn genotypese0
- Outcome
- Malate and nitrate concentrationse0
- Direction
- negatively correlatede0
- Value
- seven of eighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Malate and nitrate concentrations in the leaf tissue of seven of eight corn genotypes grown under comparable and normal (300 mul/l CO(2)) environments, were negatively correlated”
Claim · model-written summary
Increasing root potassium carbonate progressively increased root malate concentration.
- Taxon
- corn seedlingsZea mays subsp. mayse1
- Treatment
- increasing concentrations of potassium carbonate with or without potassium sulfatee0
- Outcome
- malate concentrations in the rootse0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exposure of roots to increasing concentrations of potassium carbonate with or without potassium sulfate caused a progressive increase in malate concentrations in the roots”
e1“corn seedlings (Zea mays L.)”
Claim · model-written summary
Following transfer to nitrate medium, nitrate accumulation was inversely related to initial root malate concentration.
- Taxon
- corn seedlingsZea mays subsp. mayse1
- Treatment
- nitrate mediume0
- Compound
- malatee0
- Outcome
- accumulation of nitratee0
- Direction
- inversely relatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When these roots were subsequently transferred to a nitrate medium, the accumulation of nitrate was inversely related to the initial malate concentrations”
e1“corn seedlings (Zea mays L.)”
The same questions in other papers
co2 · physiology: enzyme activity · Zea mays (maize)Positive and negative results
2 in the opposite direction
- no effect
- negative
co2 · nutrient: content · Zea mays (maize)Positive and negative results
4 papers in the same direction as this paper · 8 in the opposite direction
- no effect
- no effect
- negative
9 papers more in this group
See all 13 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.