Abstract
ABSTRACT Chlorophyll fluorescence and internal patterns of 14 CO 2 fixation were measured in sun and shade leaves of spinach after treatment with various light intensities. When sun leaves were irradiated with 2000μmol m −2 s −1 for 2h, F V / F M decreased by about 15%, but 14 CO 2 fixation was unaffected, whereas shade leaves exhibited a 21% decrease in F v / F M and a 25% decrease in 14 CO 2 fixation. Irradiation of sun and shade leaves with 4000μmol m −1 for 4 h decreased F V / F M by 30% in sun leaves and 40% in shade leaves, while total 14 CO 2 fixation decreased by 41% in sun leaves and 55% in shade leaves. After light treatment, gradients of CO 2 fixation across leaves were determined by measuring 14 CO 2 fixed in paradermal leaf sections after a 10s pulse of 14 CO 2 . Gradients of 14 CO 2 fixation in control sun and shade leaves were identified when expressed on a relative basis and normalized for leaf depth. Treatment of leaves with 2000 μmol PAR m −2 s −1 for 2h did not after patterns of carbon fixation across sun leaves, but slightly altered the pattern in shade leaves. In contrast, treatment of sun and shade leaves with 4000μmol m −2 s −1 for 4h decreased carbon fixation more in the palisade mesophyll cells than in the spongy mesophyll cells of sun and shade leaves, and fixation in medial tissue of shade leaves was dramatically decreased compared to the adaxial and abaxial tissue. The interaction between leaf anatomy and biochemical parameters involved in tolerance to photoinhibition in spinach is discussed.
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Claims 13
Claim · model-written summary
At 2000 μmol for 2 h, sun-leaf fluorescence efficiency fell about 15%.
- Taxon
- spinach
Spinacia oleraceat0 - Organ / stage
- sun leavese0
- Treatment
- 2000μmol m −2 s −1 for 2he0
- Outcome
- F V / F Me0
- Direction
- decreasede0
- Value
- about 15%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When sun leaves were irradiated with 2000μmol m −2 s −1 for 2h, F V / F M decreased by about 15%”
t0“leaves of spinach”
Claim · model-written summary
At 2000 μmol for 2 h, sun-leaf carbon fixation was unaffected.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- sun leavese0
- Treatment
- 2000μmol m −2 s −1 for 2he0
- Outcome
- 14 CO 2 fixatione0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When sun leaves were irradiated with 2000μmol m −2 s −1 for 2h, F V / F M decreased by about 15%, but 14 CO 2 fixation was unaffected”
t0“leaves of spinach”
Claim · model-written summary
At 2000 μmol for 2 h, shade-leaf fluorescence efficiency fell 21%.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- shade leavese0
- Treatment
- 2000μmol m −2 s −1 for 2ht1
- Outcome
- F v / F Me0
- Direction
- decreasee0
- Value
- 21%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shade leaves exhibited a 21% decrease in F v / F M and a 25% decrease in 14 CO 2 fixation”
t0“leaves of spinach”
t1“2000μmol m −2 s −1 for 2h”
Claim · model-written summary
At 2000 μmol for 2 h, shade-leaf carbon fixation fell 25%.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- shade leavese0
- Treatment
- 2000μmol m −2 s −1 for 2ht1
- Outcome
- 14 CO 2 fixatione0
- Direction
- decreasee0
- Value
- 25%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shade leaves exhibited a 21% decrease in F v / F M and a 25% decrease in 14 CO 2 fixation”
t0“leaves of spinach”
t1“2000μmol m −2 s −1 for 2h”
Claim · model-written summary
At 4000 μmol for 4 h, sun-leaf fluorescence efficiency fell 30%.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- sun leavese0
- Treatment
- 4000μmol m −1 for 4 he0
- Outcome
- F V / F Me0
- Direction
- decreasede0
- Value
- 30%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irradiation of sun and shade leaves with 4000μmol m −1 for 4 h decreased F V / F M by 30% in sun leaves and 40% in shade leaves”
t0“leaves of spinach”
Claim · model-written summary
At 4000 μmol for 4 h, shade-leaf fluorescence efficiency fell 40%.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- shade leavese0
- Treatment
- 4000μmol m −1 for 4 he0
- Outcome
- F V / F Me0
- Direction
- decreasede0
- Value
- 40%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irradiation of sun and shade leaves with 4000μmol m −1 for 4 h decreased F V / F M by 30% in sun leaves and 40% in shade leaves”
t0“leaves of spinach”
Claim · model-written summary
At 4000 μmol for 4 h, sun-leaf carbon fixation fell 41%.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- sun leavese0
- Treatment
- 4000μmol m −1 for 4 ht1
- Outcome
- total 14 CO 2 fixatione0
- Direction
- decreasede0
- Value
- 41%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total 14 CO 2 fixation decreased by 41% in sun leaves and 55% in shade leaves”
t0“leaves of spinach”
t1“4000μmol m −1 for 4 h”
Claim · model-written summary
At 4000 μmol for 4 h, shade-leaf carbon fixation fell 55%.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- shade leavese0
- Treatment
- 4000μmol m −1 for 4 ht1
- Outcome
- total 14 CO 2 fixatione0
- Direction
- decreasede0
- Value
- 55%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total 14 CO 2 fixation decreased by 41% in sun leaves and 55% in shade leaves”
t0“leaves of spinach”
t1“4000μmol m −1 for 4 h”
Claim · model-written summary
Control sun and shade leaves had normalized carbon-fixation gradients.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- sun and shade leavese0
- Outcome
- Gradients of 14 CO 2 fixatione0
- Qualifier
- normalized for leaf depthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Gradients of 14 CO 2 fixation in control sun and shade leaves were identified when expressed on a relative basis and normalized for leaf depth”
t0“leaves of spinach”
Claim · model-written summary
The 2000 μmol treatment did not alter sun-leaf fixation patterns.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- 2000 μmol PAR m −2 s −1 for 2he0
- Outcome
- patterns of carbon fixation across sun leavese0
- Direction
- did not aftere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of leaves with 2000 μmol PAR m −2 s −1 for 2h did not after patterns of carbon fixation across sun leaves”
t0“leaves of spinach”
Claim · model-written summary
The 2000 μmol treatment slightly altered shade-leaf fixation pattern.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- 2000 μmol PAR m −2 s −1 for 2he0
- Outcome
- pattern in shade leavese0
- Direction
- slightly alterede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatment of leaves with 2000 μmol PAR m −2 s −1 for 2h did not after patterns of carbon fixation across sun leaves, but slightly altered the pattern in shade leaves”
t0“leaves of spinach”
Claim · model-written summary
The 4000 μmol treatment depressed fixation more in palisade than spongy mesophyll.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- palisade mesophyll cellse0
- Treatment
- 4000μmol m −2 s −1 for 4he0
- Outcome
- carbon fixatione0
- Direction
- decreasede0
- Comparator
- spongy mesophyll cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“treatment of sun and shade leaves with 4000μmol m −2 s −1 for 4h decreased carbon fixation more in the palisade mesophyll cells than in the spongy mesophyll cells of sun and shade leaves”
t0“leaves of spinach”
Claim · model-written summary
The 4000 μmol treatment dramatically depressed medial shade-leaf fixation relative to surface tissue.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- 4000μmol m −2 s −1 for 4ht1
- Outcome
- fixation in medial tissue of shade leavese0
- Direction
- dramatically decreasede0
- Comparator
- adaxial and abaxial tissuee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fixation in medial tissue of shade leaves was dramatically decreased compared to the adaxial and abaxial tissue”
t0“leaves of spinach”
t1“4000μmol m −2 s −1 for 4h”
The same questions in other papers
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