Abstract
Tree nutrient research concentrated on endogenous C and N remobilisation in spring has neglected to acknowledge the possibilities of significant effects of N uptake before bud break, especially on the quality of regrowth and N reserve remobilisation. To investigate this subject, experimental studies were performed on young poplars (Populus tremula×Populus alba, clone INRA 717-1B4) grown with a controlled nutrient supply: (i) without N, 'control'; (ii) N supplied throughout the course of the experiment, 'N-supply'; and (iii) N supplied only before bud break, 'N-pulse'. Results confirm the hypothesis that poplar scions can significantly take up nitrate before bud break, amounting to ~34% of the total N stored the previous year. After bud break, emerging leaves restart the sap flow, which increased nitrate uptake to support the regrowth. N-pulse and N-supply treatments were found to have significant effects shortly after a growth period, i.e. by increasing N content of all tissues (e.g. 37 and 81% in new shoots respectively), leaf area (18 and 29%) and specific leaf area (20 and 35%). Therefore, results confirm the hypothesis that early N supply plays a significant role in the N status and N remobilisation involved in the spring regrowth of young trees.
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Claims 9
Claim · model-written summary
Poplar scions took up nitrate before bud break equal to about 34% of prior-year stored nitrogen.
- Outcome
- take up nitrate before bud breake0
- Value
- ~34%e0
- Qualifier
- of the total N stored the previous yeare0
PopulusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“poplar scions can significantly take up nitrate before bud break, amounting to ~34% of the total N stored the previous year.”
Claim · model-written summary
After bud break, emerging leaves restarted sap flow and nitrate uptake increased.
- Organ / stage
- emerging leavese0
- Outcome
- nitrate uptakee0
- Direction
- increasede0
- Qualifier
- restart the sap flowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After bud break, emerging leaves restart the sap flow, which increased nitrate uptake to support the regrowth.”
t0“young poplars”
Claim · model-written summary
N-pulse increased new-shoot nitrogen content by 37%.
- Organ / stage
- new shootse0
- Treatment
- N-pulsee0
- Outcome
- N content of all tissuese0
- Direction
- increasinge0
- Value
- 37 and 81%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N-pulse and N-supply treatments were found to have significant effects shortly after a growth period, i.e. by increasing N content of all tissues (e.g. 37 and 81% in new shoots respectively)”
t0“young poplars”
Claim · model-written summary
N-supply increased new-shoot nitrogen content by 81%.
- Organ / stage
- new shootse0
- Treatment
- N-supplye0
- Outcome
- N content of all tissuese0
- Direction
- increasinge0
- Value
- 81%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N-pulse and N-supply treatments were found to have significant effects shortly after a growth period, i.e. by increasing N content of all tissues (e.g. 37 and 81% in new shoots respectively)”
t0“young poplars”
Claim · model-written summary
N-pulse increased leaf area by 18%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N-pulse and N-supply treatments were found to have significant effects shortly after a growth period, i.e. by increasing N content of all tissues (e.g. 37 and 81% in new shoots respectively), leaf area (18 and 29%) and specific leaf area (20 and 35%).”
t0“young poplars”
Claim · model-written summary
N-supply increased leaf area by 29%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N-pulse and N-supply treatments were found to have significant effects shortly after a growth period, i.e. by increasing N content of all tissues (e.g. 37 and 81% in new shoots respectively), leaf area (18 and 29%) and specific leaf area (20 and 35%).”
t0“young poplars”
Claim · model-written summary
N-pulse increased specific leaf area by 20%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N-pulse and N-supply treatments were found to have significant effects shortly after a growth period, i.e. by increasing N content of all tissues (e.g. 37 and 81% in new shoots respectively), leaf area (18 and 29%) and specific leaf area (20 and 35%).”
t0“young poplars”
Claim · model-written summary
N-supply increased specific leaf area by 35%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N-pulse and N-supply treatments were found to have significant effects shortly after a growth period, i.e. by increasing N content of all tissues (e.g. 37 and 81% in new shoots respectively), leaf area (18 and 29%) and specific leaf area (20 and 35%).”
t0“young poplars”
Claim · model-written summary
Early nitrogen supply played a significant role in nitrogen status and remobilisation during spring regrowth.
Verbatim
e0“early N supply plays a significant role in the N status and N remobilisation involved in the spring regrowth of young trees.”
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See all 23 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.