Abstract
To investigate the effects of nitrogen (N) application rate and planting density (D) on the contents of lipid and free fatty acid, fatty acid composition, yield and quality of rice grain, a field experiment was conducted using Koshihikari (japonica) as experimental material from 2021 to 2022 with three N levels (90, 150 and 210 kg ha -1 , denoted as N1, N2 and N3, respectively) and three transplanting densities (19.0 × 10 4 , 26.7 × 10 4 and 40.0 × 10 4 plants ha -1 , denoted as D1, D2 and D3, respectively). The results showed that N application rate and planting density had highly significant impacts only on the contents of free fatty acid and saturated fatty acid, respectively. Increased N and planting density enhanced the contents of lipid (29.41 mg g -1 ) and free fatty acid (21.47%). The highest values were obtained under N3D3 increasing by 7.02% and 3.23 percentage points, respectively, compared to other treatments. No significant differences in lipid content were found among treatments, whereas free fatty acid exhibited significant differences. The unsaturated fatty acid content increased with increasing N but first decreased and then increased with increasing planting density, while saturated fatty acid content showed the opposite trend. Appropriate N level and planting density improved the relative chlorophyll content and net photosynthetic rate of rice flag leaves, as well as increased grain yield, effective panicle number and spikelete number per panicle, but decreased the seed setting rate. Under N2D2, the relative chlorophyll content and net photosynthetic rate remained relatively high throughout the grain filling stage, resulting in the highest grain yield, with increases of 43.87-47.03% compared to other treatments. A moderate N level improved the milling quality of rice, while increased planting density reduced it. However, both increased N and planting density reduced the appearance quality and cooking and eating quality of rice. Overall, the effects of increasing N application rate and planting density on enhancing rice lipid and free fatty acid contents were limited. A combination of 150 kg ha -1 N application rate and 26.7 × 10 4 plants ha -1 was recommended for achieving relatively higher yield, lipid content and better grain quality.
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Claims 20
Claim · model-written summary
Nitrogen rate significantly affected free fatty acid content.
- Taxon
- rice
Oryza sativat0 - Treatment
- N application ratee0
- Outcome
- contents of free fatty acide0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N application rate and planting density had highly significant impacts only on the contents of free fatty acid and saturated fatty acid, respectively”
t0“rice”
Claim · model-written summary
Planting density significantly affected saturated fatty acid content.
- Taxon
- riceOryza sativat0
- Treatment
- planting densitye0
- Outcome
- saturated fatty acide0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N application rate and planting density had highly significant impacts only on the contents of free fatty acid and saturated fatty acid, respectively”
t0“rice”
Claim · model-written summary
Increased nitrogen and density enhanced lipid content to 29.41 mg g -1.
- Taxon
- riceOryza sativat0
- Treatment
- Increased N and planting densitye0
- Outcome
- contents of lipide0
- Direction
- enhancede0
- Value
- 29.41 mg g -1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased N and planting density enhanced the contents of lipid (29.41 mg g -1 ) and free fatty acid (21.47%)”
t0“rice”
Claim · model-written summary
Increased nitrogen and density enhanced free fatty acid content to 21.47%.
- Taxon
- riceOryza sativat0
- Treatment
- Increased N and planting densitye0
- Outcome
- free fatty acide0
- Direction
- enhancede0
- Value
- 21.47%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased N and planting density enhanced the contents of lipid (29.41 mg g -1 ) and free fatty acid (21.47%)”
t0“rice”
Claim · model-written summary
N3D3 raised lipid content 7.02% compared with other treatments.
- Taxon
- riceOryza sativat0
- Treatment
- N3D3e0
- Outcome
- highest valuese0
- Direction
- increasinge0
- Value
- 7.02%e0
- Comparator
- other treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest values were obtained under N3D3 increasing by 7.02% and 3.23 percentage points, respectively, compared to other treatments”
t0“rice”
Claim · model-written summary
N3D3 raised free fatty acid by 3.23 percentage points.
- Taxon
- riceOryza sativat0
- Treatment
- N3D3e0
- Outcome
- highest valuese0
- Direction
- increasinge0
- Value
- 3.23 percentage pointse0
- Comparator
- other treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest values were obtained under N3D3 increasing by 7.02% and 3.23 percentage points, respectively, compared to other treatments”
t0“rice”
Claim · model-written summary
Lipid content had no significant treatment differences.
- Taxon
- riceOryza sativat0
- Outcome
- lipid contente0
- Direction
- No significant differencese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No significant differences in lipid content were found among treatments”
t0“rice”
Claim · model-written summary
Free fatty acid differed significantly among treatments.
- Taxon
- riceOryza sativat0
- Outcome
- free fatty acide0
- Direction
- significant differencese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“free fatty acid exhibited significant differences”
t0“rice”
Claim · model-written summary
Unsaturated fatty acid increased with nitrogen.
- Taxon
- riceOryza sativat0
- Treatment
- increasing Ne0
- Outcome
- unsaturated fatty acid contente0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The unsaturated fatty acid content increased with increasing N”
t0“rice”
Claim · model-written summary
Unsaturated fatty acid first decreased and then increased with density.
- Taxon
- riceOryza sativat0
- Treatment
- increasing planting densitye0
- Outcome
- unsaturated fatty acid contente1
- Direction
- first decreased and then increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“first decreased and then increased with increasing planting density”
t0“rice”
e1“The unsaturated fatty acid content increased with increasing N”
Claim · model-written summary
Saturated fatty acid showed the opposite nitrogen and density trends.
- Taxon
- riceOryza sativat0
- Outcome
- saturated fatty acid contente0
Not reportedTreatmentComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“saturated fatty acid content showed the opposite trend”
t0“rice”
Claim · model-written summary
Appropriate nitrogen and density improved flag leaf chlorophyll and photosynthetic rate.
- Taxon
- riceOryza sativae0
- Treatment
- Appropriate N level and planting densitye0
- Outcome
- relative chlorophyll content and net photosynthetic ratee0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Appropriate N level and planting density improved the relative chlorophyll content and net photosynthetic rate of rice flag leaves”
Claim · model-written summary
Appropriate nitrogen and density increased yield, effective panicle number and spikelets per panicle.
- Taxon
- riceOryza sativat0
- Outcome
- grain yield, effective panicle number and spikelete number per paniclee0
- Direction
- increasede0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased grain yield, effective panicle number and spikelete number per panicle”
t0“rice”
Claim · model-written summary
Appropriate nitrogen and density decreased seed setting rate.
- Taxon
- riceOryza sativat0
- Outcome
- seed setting ratee0
- Direction
- decreasede0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreased the seed setting rate”
t0“rice”
Claim · model-written summary
N2D2 produced the highest grain yield, 43.87-47.03% above other treatments.
- Taxon
- riceOryza sativat0
- Outcome
- grain yielde0
- Direction
- higheste0
- Value
- 43.87-47.03%e0
- Comparator
- other treatmentse0
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“resulting in the highest grain yield, with increases of 43.87-47.03% compared to other treatments”
t0“rice”
Claim · model-written summary
Moderate nitrogen improved milling quality.
- Taxon
- riceOryza sativae0
- Treatment
- A moderate N levele0
- Outcome
- milling qualitye0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A moderate N level improved the milling quality of rice”
Claim · model-written summary
Higher planting density reduced milling quality.
- Taxon
- riceOryza sativat0
- Treatment
- increased planting densitye0
- Outcome
- milling qualitye1
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased planting density reduced it”
t0“rice”
e1“A moderate N level improved the milling quality of rice”
Claim · model-written summary
Increased nitrogen and density reduced appearance quality.
- Taxon
- riceOryza sativae0
- Treatment
- increased N and planting densitye0
- Outcome
- appearance qualitye0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both increased N and planting density reduced the appearance quality and cooking and eating quality of rice”
Claim · model-written summary
Increased nitrogen and density reduced cooking and eating quality.
- Taxon
- riceOryza sativae0
- Treatment
- increased N and planting densitye0
- Outcome
- cooking and eating qualitye0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both increased N and planting density reduced the appearance quality and cooking and eating quality of rice”
Claim · model-written summary
The authors recommend 150 kg ha -1 nitrogen and 26.7 × 10 4 plants ha -1 for yield, lipid and grain quality.
- Taxon
- riceOryza sativat0
- Treatment
- 150 kg ha -1 N application ratee0
- Outcome
- relatively higher yield, lipid content and better grain qualitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A combination of 150 kg ha -1 N application rate and 26.7 × 10 4 plants ha -1 was recommended for achieving relatively higher yield, lipid content and better grain quality”
t0“rice”
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