Abstract
Remobilization of stored nitrogen (N) plays an important role in the early growth of deciduous trees in spring. Several environmental factors can modulate N remobilization, but whether water stress is one such factors is unknown. This study analyzes how the size of N storage in Quercus variabilis Blume seedlings interacts with water stress to affect N remobilization, uptake and new growth. This information is important for improving success of forest tree plantations under dry spring conditions. During the first growing season, we produced seedlings with distinct N content by applying two fall N fertilization rates (12 or 24 mg N per seedling) using 15N-enriched fertilizer. At the beginning of the second growing season, a new experiment was started where seedlings were transplanted into larger pots and subjected to two watering levels (85 or 40% of field capacity). The plants were sampled at 4 weeks (T1), 8 weeks (T2) and 12 weeks (T3) after transplanting. Low watering reduced the growth of high and low N seedlings, but high N seedlings showed greater growth than low N seedlings. During bud burst and initial shoot elongation (T1), restricted watering, which induced a moderate water stress, did not affect the amount of N remobilized from roots, the major source of stored N source at this growth stage. This suggests that high N storage can partially counteract the negative effect of moderate water stress on early growth. At T1, water stress did not affect N uptake, and high N content seedlings absorbed significantly less soil N than did low N content seedlings. At T3, in contrast, water stress was the main determinant for N uptake, with drought-stressed plants showing lower uptake than well-watered plants. We conclude that moderate drought does not inhibit N remobilization from the major storage organ at early growth stages in spring, and that increasing N storage of planted seedlings through fall fertilization can mitigate the negative effect of moderate spring drought on growth.
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Claims 7
Claim · model-written summary
Low watering reduced growth in both high and low nitrogen seedlings.
- Taxon
- Quercus variabilis Blume
Quercus variabilise1 - Treatment
- Low wateringe0
- Outcome
- growthe0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low watering reduced the growth of high and low N seedlings”
e1“Quercus variabilis Blume seedlings”
Claim · model-written summary
High nitrogen seedlings grew more than low nitrogen seedlings.
- Taxon
- Quercus variabilis BlumeQuercus variabilise1
- Treatment
- high N seedlingse0
- Outcome
- growthe0
- Direction
- greatere0
- Comparator
- low N seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high N seedlings showed greater growth than low N seedlings”
e1“Quercus variabilis Blume seedlings”
Claim · model-written summary
Restricted watering did not affect nitrogen remobilization from roots during bud burst and initial shoot elongation.
- Taxon
- Quercus variabilis BlumeQuercus variabilise1
- Organ / stage
- rootse0
- Treatment
- restricted wateringe0
- Outcome
- amount of N remobilized from rootse0
- Direction
- did not affecte0
- Qualifier
- During bud burst and initial shoot elongation (T1)e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During bud burst and initial shoot elongation (T1), restricted watering, which induced a moderate water stress, did not affect the amount of N remobilized from roots”
e1“Quercus variabilis Blume seedlings”
Claim · model-written summary
At T1, water stress did not affect nitrogen uptake.
- Taxon
- Quercus variabilis BlumeQuercus variabilise1
- Treatment
- water stresse0
- Outcome
- N uptakee0
- Direction
- did not affecte0
- Qualifier
- At T1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At T1, water stress did not affect N uptake”
e1“Quercus variabilis Blume seedlings”
Claim · model-written summary
At T1, high nitrogen seedlings absorbed significantly less soil nitrogen than low nitrogen seedlings.
- Taxon
- Quercus variabilis BlumeQuercus variabilise1
- Treatment
- high N content seedlingse0
- Outcome
- soil Ne0
- Direction
- lesse0
- Comparator
- low N content seedlingse0
Not reportedQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high N content seedlings absorbed significantly less soil N than did low N content seedlings”
e1“Quercus variabilis Blume seedlings”
Claim · model-written summary
At T3, drought stressed plants had lower nitrogen uptake than well watered plants.
- Taxon
- Quercus variabilis BlumeQuercus variabilise1
- Treatment
- drought-stressed plantse0
- Outcome
- N uptakee0
- Direction
- lowere0
- Qualifier
- At T3e0
- Comparator
- well-watered plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At T3, in contrast, water stress was the main determinant for N uptake, with drought-stressed plants showing lower uptake than well-watered plants.”
e1“Quercus variabilis Blume seedlings”
Claim · model-written summary
The authors conclude that fall nitrogen fertilization to increase stored nitrogen can mitigate moderate spring drought effects on growth.
- Taxon
- Quercus variabilis BlumeQuercus variabilise1
- Treatment
- fall fertilizatione0
- Outcome
- mitigate the negative effect of moderate spring drought on growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing N storage of planted seedlings through fall fertilization can mitigate the negative effect of moderate spring drought on growth”
e1“Quercus variabilis Blume seedlings”
The same questions in other papers
drought · nutrient: content · Quercus variabilisResults agree
1 paper in the same direction as this paper
- 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.