Abstract
Specific leaf nitrogen (SLN, g/m 2 ) is knownto affect radiation use efficiency (RUE, g/MJ) in different crops. However, this association and importance have not been well established over a range of different nitrogen regimes for field‐grown sunflower ( Helianthus annuus L.). An experiment was conducted to investigate different combinations and rates of applied nitrogen on SLN, RUE, and growth of sunflower. A fully irrigated crop was sown on an alluvial‐prairie soil (Fluventic Haplustoll) and treated with five combinations of applied nitrogen. Greater nitrogen increased biomass, grain number, and yield, but did not affect harvest index energy‐corrected for oil (0.4) or canopy extinction coefficient (0.88). Decreases in biomass accumulation under low nitrogen treatments were associated with reductions in leaf area index (LAI) and light interception. When SLN and RUE were examinedto gether, both were less in the anthesis to physiological maturity period, but relatively stable between bud visible and anthesis. However, the effects of canopy SLN on RUE were confounded by high SLN in the top of the canopy and the crop maintaining SLN by reducing LAI. Measurementosf leaf CO 2 assimilation and theoretical analyses of RUE supported that RUE was related to SLN. The major effect of nitrogen on early growth of sunflower was mediated by leaf area and the distribution of SLN in the canopy rather than direct effects of canopy SLN on RUE alone. Greater responses of RUE to SLN are more evident later in growth, and may be related to the demand of nitrogen by the grain.
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Claims 10
Claim · model-written summary
Greater applied nitrogen increased biomass, grain number and yield of field sunflower.
- Taxon
- sunflower
Helianthus annuust0 - Treatment
- Greater nitrogene1
- Outcome
- biomass, grain number, and yielde1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Greater nitrogen increased biomass, grain number, and yield, but did not affect harvest index energy‐corrected for oil (0.4) or canopy extinction coefficient (0.88)”
t0“Sunflower”
Claim · model-written summary
Greater nitrogen did not affect harvest index energy-corrected for oil (0.4) in sunflower.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- Greater nitrogene1
- Outcome
- harvest index energy‐corrected for oile1
- Direction
- did not affecte1
- Value
- 0.4e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Greater nitrogen increased biomass, grain number, and yield, but did not affect harvest index energy‐corrected for oil (0.4) or canopy extinction coefficient (0.88)”
t0“Sunflower”
Claim · model-written summary
Greater nitrogen did not affect canopy extinction coefficient (0.88) in sunflower.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- Greater nitrogene1
- Outcome
- canopy extinction coefficiente1
- Direction
- did not affecte1
- Value
- 0.88e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Greater nitrogen increased biomass, grain number, and yield, but did not affect harvest index energy‐corrected for oil (0.4) or canopy extinction coefficient (0.88)”
t0“Sunflower”
Claim · model-written summary
Decreases in biomass accumulation under low nitrogen treatments were associated with reductions in leaf area index and light interception.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- low nitrogen treatmentse1
- Outcome
- biomass accumulatione1
- Direction
- Decreasese1
- Qualifier
- associated with reductions in leaf area index (LAI) and light interceptione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Decreases in biomass accumulation under low nitrogen treatments were associated with reductions in leaf area index (LAI) and light interception”
t0“Sunflower”
Claim · model-written summary
Specific leaf nitrogen and radiation use efficiency were both lower in the anthesis to physiological maturity period.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- anthesis to physiological maturity periode1
- Outcome
- SLN and RUEe1
- Direction
- lesse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“When SLN and RUE were examinedto gether, both were less in the anthesis to physiological maturity period, but relatively stable between bud visible and anthesis”
t0“Sunflower”
Claim · model-written summary
Specific leaf nitrogen and radiation use efficiency were relatively stable between bud visible and anthesis.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- bud visible and anthesise1
- Outcome
- SLN and RUEe1
- Direction
- relatively stablee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“When SLN and RUE were examinedto gether, both were less in the anthesis to physiological maturity period, but relatively stable between bud visible and anthesis”
t0“Sunflower”
Claim · model-written summary
The effects of canopy specific leaf nitrogen on radiation use efficiency were confounded by high SLN in the top of the canopy and by the crop maintaining SLN by reducing LAI.
- Taxon
- sunflowerHelianthus annuust0
- Outcome
- effects of canopy SLN on RUEe1
- Qualifier
- confounded by high SLN in the top of the canopy and the crop maintaining SLN by reducing LAIe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the effects of canopy SLN on RUE were confounded by high SLN in the top of the canopy and the crop maintaining SLN by reducing LAI”
t0“Sunflower”
Claim · model-written summary
Leaf CO2 assimilation measurements and theoretical analyses of RUE supported that radiation use efficiency was related to specific leaf nitrogen.
- Taxon
- sunflowerHelianthus annuust0
- Compound
- SLNe1
- Outcome
- RUEe1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Measurementosf leaf CO 2 assimilation and theoretical analyses of RUE supported that RUE was related to SLN”
t0“Sunflower”
Claim · model-written summary
The major effect of nitrogen on early growth of sunflower was mediated by leaf area and the distribution of SLN in the canopy rather than by direct effects of canopy SLN on RUE alone.
- Taxon
- sunflowerHelianthus annuuse1
- Treatment
- nitrogene1
- Outcome
- early growthe1
- Qualifier
- mediated by leaf area and the distribution of SLN in the canopye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The major effect of nitrogen on early growth of sunflower was mediated by leaf area and the distribution of SLN in the canopy rather than direct effects of canopy SLN on RUE alone”
Claim · model-written summary
Greater responses of RUE to SLN were more evident later in growth.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- later in growthe1
- Outcome
- responses of RUE to SLNe1
- Direction
- Greatere1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Greater responses of RUE to SLN are more evident later in growth”
t0“Sunflower”
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See all 196 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.