Abstract
Evaluating the impact of increasing CO 2 on rice quality is becoming a global concern. However, whether adjusting the source-sink ratio will affect the response of rice grain quality to elevated CO 2 concentrations remains unknown. In 2016–2018, we conducted a free-air CO 2 enrichment experiment using a popular japonica cultivar grown at ambient and elevated CO 2 levels (eCO 2 , increased by 200 ppm), reducing the source-sink ratio via cutting leaves (LC) at the heading stage, to investigate the effects of eCO 2 and LC and their interactions on rice processing, appearance, nutrition, and eating quality. Averaged across 3 years, eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%) but increased chalky grain percentage (+ 22.3%) and chalkiness degree (+ 26.3%). Markedly, eCO 2 increased peak viscosity (+ 2.9%) and minimum viscosity (+ 3.8%) but decreased setback (−96.1%) of powder rice and increased the appearance (+ 4.5%), stickiness (+ 3.5%) and balance degree (+ 4.8%) of cooked rice, while decreasing the hardness (−6.7%), resulting in better palatability (+ 4.0%). Further, eCO 2 significantly decreased the concentrations of protein, Ca, S, and Cu by 5.3, 4.7, 2.2, and 9.6%, respectively, but increased K concentration by 3.9%. Responses of nutritional quality in different grain positions (brown and milled rice) to eCO 2 showed the same trend. Compared with control treatment, LC significantly increased chalky grain percentage, chalkiness degree, protein concentration, mineral element levels (except for B and Mn), and phytic acid concentration. Our results indicate that eCO 2 reduced rice processing suitability, appearance, and nutritional quality but improved the eating quality. Rice quality varied significantly among years; however, few CO 2 by year, CO 2 by LC, or CO 2 by grain position interactions were detected, indicating that the effects of eCO 2 on rice quality varied little with the growing seasons, the decrease in the source-sink ratios or the different grain positions.
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Claims 20
Claim · model-written summary
Elevated CO2 decreased brown rice percentage by 0.5%.
- Taxon
- Rice
Oryza sativat0 - Treatment
- eCO 2e0
- Outcome
- brown rice percentagee0
- Direction
- decreasede0
- Value
- −0.5%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 decreased milled rice percentage by 2.1%.
- Taxon
- RiceOryza sativat0
- Treatment
- eCO 2e0
- Outcome
- milled rice percentagee0
- Direction
- decreasede0
- Value
- −2.1%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 decreased head rice percentage by 4.2%.
- Taxon
- RiceOryza sativat0
- Treatment
- eCO 2e0
- Outcome
- head rice percentagee0
- Direction
- decreasede0
- Value
- −4.2%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 increased chalky grain percentage by 22.3%.
- Taxon
- RiceOryza sativat0
- Treatment
- eCO 2e1
- Outcome
- chalky grain percentagee0
- Direction
- increasede0
- Value
- + 22.3%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased chalky grain percentage (+ 22.3%) and chalkiness degree (+ 26.3%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 increased chalkiness degree by 26.3%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased chalky grain percentage (+ 22.3%) and chalkiness degree (+ 26.3%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 increased peak viscosity by 2.9%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 increased peak viscosity (+ 2.9%) and minimum viscosity (+ 3.8%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 increased minimum viscosity by 3.8%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 increased peak viscosity (+ 2.9%) and minimum viscosity (+ 3.8%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 decreased rice powder setback by 96.1%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreased setback (−96.1%) of powder rice”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 increased cooked rice appearance by 4.5%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased the appearance (+ 4.5%), stickiness (+ 3.5%) and balance degree (+ 4.8%) of cooked rice”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 increased cooked rice stickiness by 3.5%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased the appearance (+ 4.5%), stickiness (+ 3.5%) and balance degree (+ 4.8%) of cooked rice”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 increased cooked rice balance degree by 4.8%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased the appearance (+ 4.5%), stickiness (+ 3.5%) and balance degree (+ 4.8%) of cooked rice”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 decreased cooked rice hardness by 6.7%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreasing the hardness (−6.7%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 improved palatability by 4.0%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“resulting in better palatability (+ 4.0%)”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 decreased protein concentration by 5.3%.
- Taxon
- RiceOryza sativat0
- Treatment
- eCO 2e0
- Outcome
- concentrations of proteine0
- Direction
- decreasede0
- Value
- 5.3e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 significantly decreased the concentrations of protein, Ca, S, and Cu by 5.3, 4.7, 2.2, and 9.6%, respectively”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 decreased Ca concentration by 4.7%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 significantly decreased the concentrations of protein, Ca, S, and Cu by 5.3, 4.7, 2.2, and 9.6%, respectively”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 decreased S concentration by 2.2%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 significantly decreased the concentrations of protein, Ca, S, and Cu by 5.3, 4.7, 2.2, and 9.6%, respectively”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 decreased Cu concentration by 9.6%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“eCO 2 significantly decreased the concentrations of protein, Ca, S, and Cu by 5.3, 4.7, 2.2, and 9.6%, respectively”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Elevated CO2 increased K concentration by 3.9%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased K concentration by 3.9%”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Leaf cutting increased chalky grain percentage and chalkiness degree.
- Taxon
- RiceOryza sativat0
- Treatment
- LCe0
- Outcome
- chalky grain percentage, chalkiness degreee0
- Direction
- increasede0
- Comparator
- control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with control treatment, LC significantly increased chalky grain percentage, chalkiness degree, protein concentration, mineral element levels (except for B and Mn), and phytic acid concentration”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
Claim · model-written summary
Leaf cutting increased protein concentration and mineral element levels other than B and Mn.
- Taxon
- RiceOryza sativat0
- Treatment
- LCe0
- Outcome
- protein concentration, mineral element levelse0
- Direction
- increasede0
- Qualifier
- except for B and Mne0
- Comparator
- control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with control treatment, LC significantly increased chalky grain percentage, chalkiness degree, protein concentration, mineral element levels (except for B and Mn), and phytic acid concentration”
t0“Rice”
e1“eCO 2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%)”
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