Abstract
Net CO2 exchange (NCE) rates and various flag leaf constituents were measured in wheat plants (Triticum aestivum L.) grown in field chambers at either 350 or 700 μL L-1 CO2. Rates of NCE decreased with leaf age in both CO2 treatments during 1977. A stimulation of NCE initially occurred in response to CO2 enrichment, but this was not observed on the final eight of 33 experimental days. Net photosynthetic rates in response to growth at elevated CO2 were decreased ca. 22% on average for all measurement dates in 1997 and when all NCE rates measured at elevated CO2 for 1995–1997 were averaged (P ≤ 0.0001). Soluble protein, α-amino nitrogen, and Chl a + b concentrations were significantly lower (P ≤ 0.0001) in elevated compared with ambient CO2-grown} wheat flag leaves in 1997. The treatment by date interactions for these flag leaf constituents were nonsignificant (P ≥ 0.05). Flag leaf storage carbohydrates were measured on 10 dates in 1997, but only starch and sucrose were affected by the elevated CO2 treatment. An increase of acid proteinase activity was observed on the last two measurement dates of this study. However, changes of acid proteinase activity were unaffected by CO2 enrichment (P ≥ 0.05) and only occurred during late stages of senescence. These findings supported the suggestion that premature senescence contributed to the photosynthetic decline observed in wheat flag leaves during growth at elevated CO2. Changes of α-amino nitrogen were correlated with photosynthetic decline, but acid proteinase activity probably was under endogenous control.
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Claims 16
Claim · model-written summary
Flag-leaf net photosynthesis fell approximately 22% under elevated CO2.
- Taxon
- wheat
Triticum aestivumt0 - Treatment
- elevated CO2e0
- Outcome
- Net photosynthetic ratese0
- Direction
- decreasede0
- Value
- ca. 22%e0
- Qualifier
- 1995–1997e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Net photosynthetic rates in response to growth at elevated CO2 were decreased ca. 22% on average for all measurement dates in 1997 and when all NCE rates measured at elevated CO2 for 1995–1997 were averaged (P ≤ 0.0001).”
t0“Wheat”
Claim · model-written summary
Net CO2 exchange declined with flag-leaf age under both CO2 treatments.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- leaf agee0
- Outcome
- Rates of NCEe0
- Direction
- decreasede0
- Qualifier
- both CO2 treatments during 1977e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rates of NCE decreased with leaf age in both CO2 treatments during 1977.”
t0“Wheat”
Claim · model-written summary
CO2 enrichment initially stimulated net CO2 exchange.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- CO2 enrichmente0
- Outcome
- NCEe0
- Direction
- stimulatione0
- Qualifier
- initiallye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A stimulation of NCE initially occurred in response to CO2 enrichment, but this was not observed on the final eight of 33 experimental days.”
t0“Wheat”
Claim · model-written summary
The stimulation was absent during the final eight of 33 experimental days.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- CO2 enrichmente0
- Outcome
- stimulation of NCEe0
- Direction
- not observede0
- Qualifier
- final eight of 33 experimental dayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A stimulation of NCE initially occurred in response to CO2 enrichment, but this was not observed on the final eight of 33 experimental days.”
t0“Wheat”
Claim · model-written summary
Soluble protein was lower in elevated versus ambient CO2-grown wheat flag leaves.
- Taxon
- wheatTriticum aestivume0
- Organ / stage
- flag leavese0
- Treatment
- elevatede0
- Outcome
- Soluble proteine0
- Direction
- lowere0
- Comparator
- ambient CO2-growne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soluble protein, α-amino nitrogen, and Chl a + b concentrations were significantly lower (P ≤ 0.0001) in elevated compared with ambient CO2-grown} wheat flag leaves in 1997.”
Claim · model-written summary
α-amino nitrogen was lower in elevated versus ambient CO2-grown wheat flag leaves.
- Taxon
- wheatTriticum aestivume0
- Organ / stage
- flag leavese0
- Treatment
- elevatede0
- Outcome
- α-amino nitrogene0
- Direction
- lowere0
- Comparator
- ambient CO2-growne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soluble protein, α-amino nitrogen, and Chl a + b concentrations were significantly lower (P ≤ 0.0001) in elevated compared with ambient CO2-grown} wheat flag leaves in 1997.”
Claim · model-written summary
Chl a + b concentrations was lower in elevated versus ambient CO2-grown wheat flag leaves.
- Taxon
- wheatTriticum aestivume0
- Organ / stage
- flag leavese0
- Treatment
- elevatede0
- Outcome
- Chl a + b concentrationse0
- Direction
- lowere0
- Comparator
- ambient CO2-growne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soluble protein, α-amino nitrogen, and Chl a + b concentrations were significantly lower (P ≤ 0.0001) in elevated compared with ambient CO2-grown} wheat flag leaves in 1997.”
Claim · model-written summary
Treatment-by-date interactions for leaf constituents were nonsignificant.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- treatment by date interactionse0
- Direction
- nonsignificante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The treatment by date interactions for these flag leaf constituents were nonsignificant (P ≥ 0.05).”
t0“Wheat”
Claim · model-written summary
Elevated CO2 affected starch.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- Flag leafe0
- Treatment
- elevated CO2 treatmente0
- Outcome
- starche0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Flag leaf storage carbohydrates were measured on 10 dates in 1997, but only starch and sucrose were affected by the elevated CO2 treatment.”
t0“Wheat”
Claim · model-written summary
Elevated CO2 affected sucrose.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- Flag leafe0
- Treatment
- elevated CO2 treatmente0
- Outcome
- sucrosee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Flag leaf storage carbohydrates were measured on 10 dates in 1997, but only starch and sucrose were affected by the elevated CO2 treatment.”
t0“Wheat”
Claim · model-written summary
Acid proteinase activity increased on the final two measurement dates.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- acid proteinase activitye0
- Direction
- increasee0
- Qualifier
- last two measurement datese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An increase of acid proteinase activity was observed on the last two measurement dates of this study.”
t0“Wheat”
Claim · model-written summary
CO2 enrichment did not affect changes in acid proteinase activity.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- CO2 enrichmente0
- Outcome
- changes of acid proteinase activitye0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, changes of acid proteinase activity were unaffected by CO2 enrichment (P ≥ 0.05) and only occurred during late stages of senescence.”
t0“Wheat”
Claim · model-written summary
Acid proteinase activity changes occurred only during late senescence.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- late stages of senescencee0
- Outcome
- changes of acid proteinase activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, changes of acid proteinase activity were unaffected by CO2 enrichment (P ≥ 0.05) and only occurred during late stages of senescence.”
t0“Wheat”
Claim · model-written summary
Authors linked premature senescence to photosynthetic decline under elevated CO2.
- Taxon
- wheatTriticum aestivume0
- Organ / stage
- flag leavese0
- Treatment
- elevated CO2e0
- Outcome
- photosynthetic declinee0
- Qualifier
- premature senescencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These findings supported the suggestion that premature senescence contributed to the photosynthetic decline observed in wheat flag leaves during growth at elevated CO2.”
Claim · model-written summary
α-amino nitrogen changes correlated with photosynthetic decline.
- Taxon
- wheatTriticum aestivumt0
- Compound
- α-amino nitrogene0
- Outcome
- photosynthetic declinee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Changes of α-amino nitrogen were correlated with photosynthetic decline, but acid proteinase activity probably was under endogenous control.”
t0“Wheat”
Claim · model-written summary
Authors suggest endogenous control of acid proteinase activity.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- acid proteinase activitye0
- Qualifier
- endogenous controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Changes of α-amino nitrogen were correlated with photosynthetic decline, but acid proteinase activity probably was under endogenous control.”
t0“Wheat”
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