Abstract
The internal cycling of nitrogen (N) has been studied in apple rootstocks grown in sand culture and subjected to a constant N supply, or defoliation, or withholding the N supply in the autumn in order to manipulate the amount of N stored over the winter. The trees subsequently received either no N or 8–0 mol N m−3 (labelled with 15N to 498 atom%) with the irrigation the following spring in order to determine the effect of the current N supply on the remobilization of N for leaf growth. Provision of an autumnal N supply delayed leaf senescence and reduced the amount of N withdrawn from leaves from 156 mg N plant−1 to 91 mg N plant−1. Loss of protein ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO) accounted for 83–87% of the soluble protein N lost during leaf senescence, there being a preferential loss of RUBISCO compared with other soluble leaf proteins. Remobilization of N from perennial woody tissues (stems and roots) in the spring was used predominantly for leaf growth. The amount of N remobilized depended upon the size of the N store, but was unaffected by the current N supply, demonstrating that fertilization of trees does not alter the efficiency with which they cycle N. Degradation of RUBISCO in the autumn accounted for between 32% and 48% of the N subsequently remobilized for leaf growth the following spring, suggesting that RUBISCO has a role as a summer store for N.
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Claims 10
Claim · model-written summary
Autumn nitrogen supply delayed apple leaf senescence.
- Taxon
- Apple Trees
Malus domesticat0 - Treatment
- autumnal N supplye0
- Outcome
- leaf senescencee0
- Direction
- delayede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Provision of an autumnal N supply delayed leaf senescence and reduced the amount of N withdrawn from leaves from 156 mg N plant−1 to 91 mg N plant−1.”
t0“Apple Trees”
Claim · model-written summary
Autumn nitrogen supply reduced nitrogen withdrawn from apple leaves from 156 to 91 mg N per plant.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- autumnal N supplye0
- Outcome
- amount of N withdrawn from leavese0
- Direction
- reducede0
- Value
- 91 mg N plant−1e0
- Qualifier
- 156 mg N plant−1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Provision of an autumnal N supply delayed leaf senescence and reduced the amount of N withdrawn from leaves from 156 mg N plant−1 to 91 mg N plant−1.”
t0“Apple Trees”
Claim · model-written summary
RUBISCO loss accounted for 83–87% of soluble protein nitrogen lost during apple leaf senescence.
- Taxon
- Apple TreesMalus domesticat0
- Gene
- ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO)e0
- Outcome
- soluble protein N lost during leaf senescencee0
- Value
- 83–87%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loss of protein ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO) accounted for 83–87% of the soluble protein N lost during leaf senescence”
t0“Apple Trees”
Claim · model-written summary
RUBISCO was preferentially lost compared with other soluble apple leaf proteins during senescence.
- Taxon
- Apple TreesMalus domesticat0
- Gene
- RUBISCOe0
- Outcome
- loss of RUBISCOe0
- Direction
- preferential losse0
- Comparator
- other soluble leaf proteinse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there being a preferential loss of RUBISCO compared with other soluble leaf proteins.”
t0“Apple Trees”
Claim · model-written summary
Nitrogen remobilized from perennial apple stems and roots in spring was used predominantly for leaf growth.
- Taxon
- Apple TreesMalus domesticat0
- Organ / stage
- perennial woody tissues (stems and roots)e0
- Outcome
- leaf growthe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Remobilization of N from perennial woody tissues (stems and roots) in the spring was used predominantly for leaf growth.”
t0“Apple Trees”
Claim · model-written summary
The amount of nitrogen remobilized in apple depended on the size of the nitrogen store.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- current N supplye0
- Outcome
- amount of N remobilizede0
- Qualifier
- size of the N storee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amount of N remobilized depended upon the size of the N store, but was unaffected by the current N supply”
t0“Apple Trees”
Claim · model-written summary
Current nitrogen supply did not affect the amount of nitrogen remobilized in apple.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- current N supplye0
- Outcome
- amount of N remobilizede0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amount of N remobilized depended upon the size of the N store, but was unaffected by the current N supply”
t0“Apple Trees”
Claim · model-written summary
Apple tree fertilization did not alter nitrogen cycling efficiency.
- Taxon
- Apple TreesMalus domesticat0
- Treatment
- fertilizatione0
- Outcome
- efficiency with which they cycle Ne0
- Direction
- does not altere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fertilization of trees does not alter the efficiency with which they cycle N.”
t0“Apple Trees”
Claim · model-written summary
Autumn RUBISCO degradation accounted for 32% to 48% of nitrogen subsequently remobilized for apple leaf growth.
- Taxon
- Apple TreesMalus domesticat0
- Gene
- RUBISCOe0
- Outcome
- N subsequently remobilized for leaf growthe0
- Value
- between 32% and 48%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Degradation of RUBISCO in the autumn accounted for between 32% and 48% of the N subsequently remobilized for leaf growth the following spring”
t0“Apple Trees”
Claim · model-written summary
The authors suggest RUBISCO serves as a summer nitrogen store in apple trees.
- Taxon
- Apple TreesMalus domesticat0
- Gene
- RUBISCOe0
- Outcome
- summer store for Ne0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“suggesting that RUBISCO has a role as a summer store for N.”
t0“Apple Trees”
The same questions in other papers
fertilization · molecular: metabolites · Malus domestica (apple)Positive and negative results
17 papers in the same direction as this paper · 31 in the opposite direction
- positive
- positive
- positive
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See all 49 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.