Abstract
ABSTRACT A simple method of growing plants in agar was exploited to investigate the effect of long‐term nitrogen (N) and phosphorus (P) deficiencies on respiratory metabolism and growth in shoots and roots of Nicotiana tabacum seedlings, and their interaction with exogenously supplied sucrose. Levels of hexose phosphates and 3‐phosphoglyceric acid (3‐PGA) were low in P‐deficient shoots and roots and high in N‐deficient shoots and roots. The ratio of hexose phosphates to 3‐PGA and levels of fructose‐2,6‐bisphosphate were high in P‐deficient plants and low in N‐deficient plants. These data reflect differences in the way metabolism was perturbed, yet both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots. Enzymes for sucrose degradation (sucrose synthase, acid and alkaline invertase) and glycolysis (phosphofructokinase, pyrophosphate‐dependent phospho‐fructokinase and pyruvate kinase) remained unaltered or declined in the shoots and roots. The accumulation of hexoses in roots of N‐ and P‐deficient plants may result from maintenance of high invertase activities relative to sucrose synthase and glycolytic enzymes in the roots. The possibility that hexose accumulation may drive preferential root growth osmotically in N and P deficiencies is discussed. The addition of sucrose to roots to further investigate the interaction of carbohydrates with growth and allocation in low N and low P produced clear effects even though endogenous levels of soluble carbohydrate were already high in the nutrient‐deficient plants. In complete nutrition, growth was stimulated, protein content particularly of the roots was increased and there was a preferential increase in activity of sucrose synthase in roots. At low P, enzyme activities in roots were increased, including sucrose synthase, and protein content increased, particularly in the roots, but there was no increase in growth. In N‐deficient plants, exogenous sucrose led to decreased protein, Rubisco and chlorophyll content in shoots, in contrast to the other conditions, and a higher protein content and a general increase of catabolic enzyme activities and growth in the roots.
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Claims 20
Claim · model-written summary
P deficiency lowered hexose phosphates and 3-PGA in shoots and roots.
- Taxon
- Nicotiana tabacum seedlings
Nicotiana tabacume0 - Treatment
- P‐deficiente1
- Outcome
- hexose phosphates and 3‐phosphoglyceric acid (3‐PGA)e1
- Direction
- lowe1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“Levels of hexose phosphates and 3‐phosphoglyceric acid (3‐PGA) were low in P‐deficient shoots and roots”
Claim · model-written summary
N deficiency raised hexose phosphates and 3-PGA in shoots and roots.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- N‐deficiente1
- Outcome
- hexose phosphates and 3‐phosphoglyceric acid (3‐PGA)e2
- Direction
- highe1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“high in N‐deficient shoots and roots”
e2“Levels of hexose phosphates and 3‐phosphoglyceric acid (3‐PGA) were low in P‐deficient shoots and roots”
Claim · model-written summary
P deficiency raised the hexose phosphate to 3-PGA ratio and fructose-2,6-bisphosphate.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- P‐deficiente1
- Outcome
- ratio of hexose phosphates to 3‐PGA and levels of fructose‐2,6‐bisphosphatee1
- Direction
- highe1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“The ratio of hexose phosphates to 3‐PGA and levels of fructose‐2,6‐bisphosphate were high in P‐deficient plants”
Claim · model-written summary
N deficiency lowered the hexose phosphate to 3-PGA ratio and fructose-2,6-bisphosphate.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- N‐deficiente1
- Outcome
- ratio of hexose phosphates to 3‐PGA and levels of fructose‐2,6‐bisphosphatee2
- Direction
- lowe1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“low in N‐deficient plants”
e2“The ratio of hexose phosphates to 3‐PGA and levels of fructose‐2,6‐bisphosphate were high in P‐deficient plants”
Claim · model-written summary
P deficiency was associated with root growth.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- deficienciese1
- Outcome
- root growthe1
- Direction
- increasede1
- Comparator
- shoot growthe1
Not reportedQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots”
Claim · model-written summary
P deficiency was associated with starch accumulation.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- deficienciese1
- Outcome
- starch accumulatione1
- Direction
- accumulatione1
Not reportedComparatorQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots”
Claim · model-written summary
P deficiency was associated with soluble carbohydrate accumulation.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- deficienciese1
- Outcome
- soluble carbohydrate accumulatione1
- Direction
- accumulatione1
Not reportedComparatorQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots”
Claim · model-written summary
N deficiency was associated with root growth.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- deficienciese1
- Outcome
- root growthe1
- Direction
- increasede1
- Comparator
- shoot growthe1
Not reportedQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots”
Claim · model-written summary
N deficiency was associated with starch accumulation.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- deficienciese1
- Outcome
- starch accumulatione1
- Direction
- accumulatione1
Not reportedComparatorQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots”
Claim · model-written summary
N deficiency was associated with soluble carbohydrate accumulation.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- deficienciese1
- Outcome
- soluble carbohydrate accumulatione1
- Direction
- accumulatione1
Not reportedComparatorQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots”
Claim · model-written summary
Enzymes for sucrose degradation and glycolysis remained unchanged or declined in shoots and roots.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Outcome
- Enzymes for sucrose degradatione1
- Direction
- remained unaltered or declinede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“Enzymes for sucrose degradation (sucrose synthase, acid and alkaline invertase) and glycolysis (phosphofructokinase, pyrophosphate‐dependent phospho‐fructokinase and pyruvate kinase) remained unaltered or declined in the shoots and roots”
Claim · model-written summary
Added sucrose stimulated growth with complete nutrition.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- sucrosee2
- Outcome
- growthe1
- Direction
- stimulatede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“In complete nutrition, growth was stimulated”
e2“The addition of sucrose to roots”
Claim · model-written summary
Added sucrose increased protein content, especially in roots, with complete nutrition.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- sucrosee2
- Outcome
- protein contente1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“protein content particularly of the roots was increased”
e2“The addition of sucrose to roots”
Claim · model-written summary
Added sucrose preferentially increased root sucrose synthase activity with complete nutrition.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- sucrosee1
- Outcome
- activity of sucrose synthasee1
- Direction
- increasee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“preferential increase in activity of sucrose synthase in roots”
Claim · model-written summary
With low P, sucrose increased root enzyme activities including sucrose synthase.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- sucrosee1
- Outcome
- enzyme activities in rootse1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“At low P, enzyme activities in roots were increased, including sucrose synthase”
Claim · model-written summary
With low P, sucrose increased protein content particularly in roots.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- sucrosee2
- Outcome
- protein contente1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“protein content increased, particularly in the roots”
e2“The addition of sucrose to roots”
Claim · model-written summary
With low P, sucrose did not increase growth.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- sucrosee2
- Outcome
- growthe1
- Direction
- no increasee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“there was no increase in growth”
e2“The addition of sucrose to roots”
Claim · model-written summary
With N deficiency, sucrose decreased shoot protein, Rubisco and chlorophyll.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- exogenous sucrosee1
- Outcome
- protein, Rubisco and chlorophyll content in shootse1
- Direction
- decreasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“In N‐deficient plants, exogenous sucrose led to decreased protein, Rubisco and chlorophyll content in shoots”
Claim · model-written summary
With N deficiency, sucrose raised root protein content.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- sucrosee2
- Outcome
- protein contente1
- Direction
- highere1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“a higher protein content and a general increase of catabolic enzyme activities and growth in the roots”
e2“The addition of sucrose to roots”
Claim · model-written summary
With N deficiency, sucrose increased root catabolic enzyme activities and growth.
- Taxon
- Nicotiana tabacum seedlingsNicotiana tabacume0
- Treatment
- sucrosee2
- Outcome
- catabolic enzyme activities and growthe1
- Direction
- increasee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nicotiana tabacum seedlings”
e1“a general increase of catabolic enzyme activities and growth in the roots”
e2“The addition of sucrose to roots”
The same questions in other papers
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12 papers in the same direction as this paper · 3 in the opposite direction
- positive
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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.