Abstract
The photosynthetic response of barley ( Hordeum vulgare L. cv. Brant) primary leaves was studied as a function of chlorosis induced by CO 2 enrichment. Leaf yellowing, measured as changes of chlorophyll a and b , was more extensive in controlled environments at elevated (680 ± 17 µl l −1 ) than at ambient (380 ± 21 µl l −1 ) CO 2 . Stomatal conductance of primary leaves was decreased by growth in elevated CO 2 between 11 and 18 days after sowing (DAS) when measured at both 380 and 680 µl l −1 CO 2 . Internal leaf CO 2 concentration (C i ) was also lower for elevated‐ compared to ambient‐CO 2 ‐grown primary leaves between 11 and 14 DAS. Results suggest that non‐stomatal factors were responsible for the decreased photosynthetic rates of elevated‐ compared to ambient‐CO 2 ‐grown primary leaves 18 DAS. Various photochemical measurements, including quantum absorptance (α), minimal (F 0 ), maximal (F m ), and variable (F v ) chlorophyll fluorescence, as well as the F v /F m ratio, were significantly decreased 18 DAS in the elevated‐ compared to ambient‐CO 2 treatment. Photochemical (qP) and nonphotochemical (qN) chlorophyll fluorescence quenching coefficients of 18‐day‐old primary leaves did not differ between CO 2 treatments. Photosynthetic electron transport rates of photosystem II were slightly lower for elevated‐ compared to ambient‐CO 2 ‐grown primary leaves 18 DAS. Concentrations of α‐amino N (i.e. free amino acids) in barley primary leaves were increased by CO 2 enrichment 10 DAS, but subsequently, α‐amino N decreased in association with photosynthetic decline. Total acid protease activity was greater in elevated‐ than in ambient‐CO 2 ‐grown leaves 18 DAS. The above findings suggest that photoinhibition and premature senescence were factors in the CO 2 ‐dependent yellowing of barley primary leaves.
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Claims 10
Claim · model-written summary
Leaf yellowing measured as chlorophyll a and b changes was more extensive in barley primary leaves grown at elevated than at ambient CO2.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Organ / stage
- primary leavest0
- Treatment
- atmospheric CO2 enrichmentt0
- Outcome
- Leaf yellowinge0
- Direction
- more extensivee0
- Comparator
- ambiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“barley primary leaves in response to atmospheric CO2 enrichment”
e0“Leaf yellowing, measured as changes of chlorophyll a and b , was more extensive in controlled environments at elevated (680 ± 17 µl l −1 ) than at ambient”
Claim · model-written summary
Stomatal conductance of barley primary leaves was decreased by growth in elevated CO2 between 11 and 18 days after sowing.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- primary leavese0
- Treatment
- elevated CO 2e0
- Outcome
- Stomatal conductancee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley primary leaves in response to atmospheric CO2 enrichment”
e0“Stomatal conductance of primary leaves was decreased by growth in elevated CO 2 between 11 and 18 days after sowing (DAS)”
Claim · model-written summary
Internal leaf CO2 concentration was lower in elevated-CO2-grown than ambient-CO2-grown barley primary leaves between 11 and 14 days after sowing.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- primary leavest0
- Treatment
- atmospheric CO2 enrichmentt0
- Outcome
- Internal leaf CO 2 concentratione0
- Direction
- lowere0
- Comparator
- ambiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley primary leaves in response to atmospheric CO2 enrichment”
e0“Internal leaf CO 2 concentration (C i ) was also lower for elevated‐ compared to ambient”
Claim · model-written summary
Photochemical measurements including quantum absorptance, F0, Fm, Fv and the Fv/Fm ratio were significantly decreased 18 days after sowing under elevated compared to ambient CO2.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- primary leavest0
- Treatment
- atmospheric CO2 enrichmentt0
- Outcome
- Various photochemical measurementse0
- Direction
- significantly decreasede0
- Comparator
- ambiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley primary leaves in response to atmospheric CO2 enrichment”
e0“Various photochemical measurements, including quantum absorptance (α), minimal (F 0 ), maximal (F m ), and variable (F v ) chlorophyll fluorescence, as well as the F v /F m ratio, were significantly decreased 18 DAS in the elevated‐ compared to ambient”
Claim · model-written summary
Photochemical and nonphotochemical chlorophyll fluorescence quenching coefficients of 18-day-old primary leaves did not differ between CO2 treatments.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- CO 2 treatmentse0
- Outcome
- chlorophyll fluorescence quenching coefficientse0
- Direction
- did not differe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley primary leaves in response to atmospheric CO2 enrichment”
e0“Photochemical (qP) and nonphotochemical (qN) chlorophyll fluorescence quenching coefficients of 18‐day‐old primary leaves did not differ between CO 2 treatments”
Claim · model-written summary
Photosynthetic electron transport rates of photosystem II were slightly lower in elevated-CO2-grown than ambient-CO2-grown primary leaves 18 days after sowing.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- primary leavest0
- Treatment
- atmospheric CO2 enrichmentt0
- Outcome
- Photosynthetic electron transport rates of photosystem IIe0
- Direction
- slightly lowere0
- Comparator
- ambiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley primary leaves in response to atmospheric CO2 enrichment”
e0“Photosynthetic electron transport rates of photosystem II were slightly lower for elevated‐ compared to ambient”
Claim · model-written summary
Concentrations of alpha-amino N (free amino acids) in barley primary leaves were increased by CO2 enrichment 10 days after sowing.
- Taxon
- barleyHordeum vulgaree0
- Organ / stage
- primary leavese0
- Treatment
- CO 2 enrichmente0
- Outcome
- Concentrations of α‐amino Ne0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentrations of α‐amino N (i.e. free amino acids) in barley primary leaves were increased by CO 2 enrichment 10 DAS”
Claim · model-written summary
After 10 days after sowing, alpha-amino N decreased in association with photosynthetic decline in barley primary leaves.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- primary leavest0
- Outcome
- α‐amino Ne0
- Direction
- decreasede0
- Qualifier
- photosynthetic declinee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley primary leaves in response to atmospheric CO2 enrichment”
e0“subsequently, α‐amino N decreased in association with photosynthetic decline”
Claim · model-written summary
Total acid protease activity was greater in elevated-CO2-grown than ambient-CO2-grown barley leaves 18 days after sowing.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- atmospheric CO2 enrichmentt0
- Outcome
- Total acid protease activitye0
- Direction
- greatere0
- Comparator
- ambiente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“barley primary leaves in response to atmospheric CO2 enrichment”
e0“Total acid protease activity was greater in elevated‐ than in ambient”
Claim · model-written summary
The authors suggest photoinhibition and premature senescence were factors in the CO2-dependent yellowing of barley primary leaves.
- Taxon
- barleyHordeum vulgaree0
- Organ / stage
- primary leavese0
- Outcome
- yellowinge0
- Qualifier
- photoinhibition and premature senescencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photoinhibition and premature senescence were factors in the CO 2 ‐dependent yellowing of barley primary leaves”
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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.