Abstract
As a keystone species for afforestation and bioeconomic applications, poplar plays vital roles in paper production, bioenergy systems, and ecological remediation. While nitrogen critically regulates poplar's rapid growth, the species' preferential utilization mechanisms for different N fertilizers remain poorly characterized. This study employed an integrated approach combining 15 N isotopic tracing, root order anatomical analysis, and nitrogen transformation gene profiling to investigate N allocation patterns and root functional specialization in poplar. Results demonstrated significantly higher 15 N uptake rates (6.26 %-120.79 %) in roots, trunks, branches, and leaves under urea treatment compared to compound fertilizer. Root absorption capacity showed an inverse correlation with root order, indicating functional differentiation across branching hierarchies. Residual fertilizer was primarily retained within the 0–40 cm soil horizon, suggesting limited vertical leaching. Molecular analysis revealed divergent microbial mediation-both fertilizers enhanced soil N mineralization but through distinct biochemical pathways: urea primarily stimulated assimilatory nitrate reduction (upregulating nasB , nasA , nasD and nirA genes), whereas compound fertilizer activated dissimilatory pathways ( nirB gene upregulation). These findings elucidate the physiological basis of N utilization preferences in poplar, demonstrating root system modularity where lower-order roots specialize in nutrient acquisition while higher orders focus on transport. This work provides mechanistic insights into optimizing fertilization strategies for poplar plantations while advancing our understanding of functional-structural relationships in woody root systems.
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Claims 7
Claim · model-written summary
Urea gave significantly higher 15N uptake rates than compound fertilizer in roots, trunks, branches and leaves of poplar.
- Organ / stage
- roots, trunks, branches, and leavese1
- Treatment
- ureae1
- Outcome
- 15 N uptake ratese1
- Direction
- highere1
- Value
- 6.26 %-120.79 %e1
- Comparator
- compound fertilizere1
PopulusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“root functions across root orders of poplar”
e1“Results demonstrated significantly higher 15 N uptake rates (6.26 %-120.79 %) in roots, trunks, branches, and leaves under urea treatment compared to compound fertilizer”
Claim · model-written summary
Root absorption capacity was inversely correlated with root order in poplar.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“root functions across root orders of poplar”
e2“Root absorption capacity showed an inverse correlation with root order”
Claim · model-written summary
Residual fertilizer was primarily retained in the 0-40 cm soil horizon, suggesting limited vertical leaching.
- Outcome
- Residual fertilizer was primarily retainede3
- Qualifier
- suggesting limited vertical leachinge3
- Setting
- 0–40 cm soil horizone3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“root functions across root orders of poplar”
e3“Residual fertilizer was primarily retained within the 0–40 cm soil horizon, suggesting limited vertical leaching”
Claim · model-written summary
Both fertilizers enhanced soil N mineralization, through distinct biochemical pathways.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“root functions across root orders of poplar”
e4“both fertilizers enhanced soil N mineralization but through distinct biochemical pathways”
Claim · model-written summary
Urea primarily stimulated assimilatory nitrate reduction, with upregulation of nasB, nasA, nasD and nirA.
- Treatment
- ureae5
- Gene
- nasB , nasA , nasD and nirAe5
- Outcome
- assimilatory nitrate reductione5
- Direction
- stimulatede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“root functions across root orders of poplar”
e5“urea primarily stimulated assimilatory nitrate reduction (upregulating nasB , nasA , nasD and nirA genes)”
Claim · model-written summary
Compound fertilizer activated dissimilatory pathways, with nirB gene upregulation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“root functions across root orders of poplar”
e6“compound fertilizer activated dissimilatory pathways ( nirB gene upregulation)”
Claim · model-written summary
Lower-order poplar roots specialize in nutrient acquisition while higher-order roots focus on transport.
- Organ / stage
- lower-order rootse7
- Outcome
- nutrient acquisitione7
- Qualifier
- higher orders focus on transporte7
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“root functions across root orders of poplar”
e7“lower-order roots specialize in nutrient acquisition while higher orders focus on transport”
The same questions in other papers
nitrogen · nutrient: content · Populus (poplar)Positive and negative results
4 papers in the same direction as this paper · 2 in the opposite direction
- negative
- no effect
- positive
3 papers more in this group
See all 7 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.