Abstract
Photosynthetic CO(2) assimilation, transpiration, ribulose-1,5-bisphosphate carboxylase (RuBPCase), and soluble protein were reduced in leaves of water-deficit (stress) ;Valencia' orange (Citrus sinensis [L.] Osbeck). Maximum photosynthetic CO(2) assimilation and transpiration, which occurred before midday for both control and stressed plants, was 58 and 40%, respectively, for the stress (-2.0 megapascals leaf water potential) as compared to the control (-0.6 megapascals leaf water potential). As water deficit became more severe in the afternoon, with water potential of -3.1 megapascals for the stressed leaves vs. -1.1 megapascals for control leaves, stressed-leaf transpiration declined and photosynthetic CO(2) assimilation rapidly dropped to zero. Water deficit decreased both activation and total activity of RuBPCase. Activation of the enzyme was about 62% (of fully activated enzyme in vitro) for the stress, compared to 80% for the control. Water deficit reduced RuBPCase initial activity by 40% and HCO(3) (-)/Mg(2+)-saturated activity by 22%. However, RuBPCase for both stressed and control leaves were similar in K(cat) (25 moles CO(2) per mole enzyme per second) and K(m) for CO(2) (18.9 micromolar). Concentrations of RuBPCase and soluble protein of stressed leaves averaged 80 and 85%, respectively, of control leaves. Thus, reductions in activation and concentration of RuBPCase in Valencia orange leaves contributed to reductions in enzyme activities during water-deficit periods. Declines in leaf photosynthesis, soluble protein, and RuBPCase activation and concentration due to water deficit were, however, recoverable at 5 days after rewatering.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 17
Claim · model-written summary
Water deficit reduced photosynthetic CO(2) assimilation in Valencia orange leaves.
- Taxon
- Citrus sinensis [L.] Osbeck
Citrus sinensise0 - Treatment
- water-deficit (stress)e0
- Outcome
- Photosynthetic CO(2) assimilatione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthetic CO(2) assimilation, transpiration, ribulose-1,5-bisphosphate carboxylase (RuBPCase), and soluble protein were reduced in leaves of water-deficit (stress) ;Valencia' orange (Citrus sinensis [L.] Osbeck).”
Claim · model-written summary
Water deficit reduced transpiration in Valencia orange leaves.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensise0
- Treatment
- water-deficit (stress)e0
- Outcome
- transpiratione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthetic CO(2) assimilation, transpiration, ribulose-1,5-bisphosphate carboxylase (RuBPCase), and soluble protein were reduced in leaves of water-deficit (stress) ;Valencia' orange (Citrus sinensis [L.] Osbeck).”
Claim · model-written summary
Maximum photosynthetic CO(2) assimilation in stressed leaves was 58% of control.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- stress (-2.0 megapascals leaf water potential)e0
- Outcome
- Maximum photosynthetic CO(2) assimilatione0
- Value
- 58e0
- Comparator
- control (-0.6 megapascals leaf water potential)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximum photosynthetic CO(2) assimilation and transpiration, which occurred before midday for both control and stressed plants, was 58 and 40%, respectively, for the stress (-2.0 megapascals leaf water potential) as compared to the control (-0.6 megapascals leaf water potential).”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
Maximum transpiration in stressed leaves was 40% of control.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- stress (-2.0 megapascals leaf water potential)e0
- Outcome
- transpiratione0
- Value
- 40%e0
- Comparator
- control (-0.6 megapascals leaf water potential)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximum photosynthetic CO(2) assimilation and transpiration, which occurred before midday for both control and stressed plants, was 58 and 40%, respectively, for the stress (-2.0 megapascals leaf water potential) as compared to the control (-0.6 megapascals leaf water potential).”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
As afternoon water deficit intensified, stressed-leaf transpiration declined.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- water deficite0
- Outcome
- stressed-leaf transpiratione0
- Direction
- declinede0
- Qualifier
- in the afternoone0
- Comparator
- control leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As water deficit became more severe in the afternoon, with water potential of -3.1 megapascals for the stressed leaves vs. -1.1 megapascals for control leaves, stressed-leaf transpiration declined and photosynthetic CO(2) assimilation rapidly dropped to zero.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
As afternoon water deficit intensified, photosynthetic CO(2) assimilation rapidly reached zero.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- water deficite0
- Outcome
- photosynthetic CO(2) assimilatione0
- Direction
- droppede0
- Value
- zeroe0
- Comparator
- control leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As water deficit became more severe in the afternoon, with water potential of -3.1 megapascals for the stressed leaves vs. -1.1 megapascals for control leaves, stressed-leaf transpiration declined and photosynthetic CO(2) assimilation rapidly dropped to zero.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
Water deficit decreased RuBPCase activation.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- Water deficite0
- Gene
- RuBPCasee0
- Outcome
- activatione0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water deficit decreased both activation and total activity of RuBPCase.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
Water deficit decreased total RuBPCase activity.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- Water deficite0
- Gene
- RuBPCasee0
- Outcome
- total activitye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water deficit decreased both activation and total activity of RuBPCase.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
RuBPCase activation was about 62% under stress versus 80% in controls.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- stresse0
- Gene
- RuBPCasee1
- Outcome
- Activation of the enzymee0
- Value
- 62%e0
- Qualifier
- 80%e0
- Comparator
- controle0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Activation of the enzyme was about 62% (of fully activated enzyme in vitro) for the stress, compared to 80% for the control.”
e1“Water deficit decreased both activation and total activity of RuBPCase.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
Water deficit reduced initial RuBPCase activity by 40%.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- Water deficite0
- Outcome
- RuBPCase initial activitye0
- Direction
- reducede0
- Value
- 40%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water deficit reduced RuBPCase initial activity by 40% and HCO(3) (-)/Mg(2+)-saturated activity by 22%.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
Water deficit reduced HCO(3) (-)/Mg(2+)-saturated RuBPCase activity by 22%.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- Water deficite0
- Outcome
- HCO(3) (-)/Mg(2+)-saturated activitye0
- Direction
- reducede0
- Value
- 22%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water deficit reduced RuBPCase initial activity by 40% and HCO(3) (-)/Mg(2+)-saturated activity by 22%.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
RuBPCase K(cat) was similar in stressed and control leaves at 25 moles CO(2) per mole enzyme per second.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Gene
- RuBPCasee0
- Outcome
- K(cat)e0
- Direction
- similare0
- Value
- 25 moles CO(2) per mole enzyme per seconde0
- Comparator
- control leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RuBPCase for both stressed and control leaves were similar in K(cat) (25 moles CO(2) per mole enzyme per second) and K(m) for CO(2) (18.9 micromolar).”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
RuBPCase K(m) for CO(2) was similar in stressed and control leaves at 18.9 micromolar.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Gene
- RuBPCasee0
- Outcome
- K(m) for CO(2)e0
- Direction
- similare0
- Value
- 18.9 micromolare0
- Comparator
- control leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RuBPCase for both stressed and control leaves were similar in K(cat) (25 moles CO(2) per mole enzyme per second) and K(m) for CO(2) (18.9 micromolar).”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
RuBPCase concentration in stressed leaves averaged 80% of controls.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Gene
- RuBPCasee0
- Outcome
- Concentrations of RuBPCasee0
- Value
- 80e0
- Comparator
- control leavese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentrations of RuBPCase and soluble protein of stressed leaves averaged 80 and 85%, respectively, of control leaves.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
Soluble protein concentration in stressed leaves averaged 85% of controls.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Outcome
- soluble proteine0
- Value
- 85%e0
- Comparator
- control leavese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentrations of RuBPCase and soluble protein of stressed leaves averaged 80 and 85%, respectively, of control leaves.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
Claim · model-written summary
Reduced RuBPCase activation and concentration contributed to reduced enzyme activity during water deficit.
- Taxon
- Valencia orangeCitrus sinensise0
- Treatment
- water-deficit periodse0
- Gene
- RuBPCasee0
- Outcome
- reductions in enzyme activitiese0
- Direction
- reductionse0
- Qualifier
- reductions in activation and concentratione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reductions in activation and concentration of RuBPCase in Valencia orange leaves contributed to reductions in enzyme activities during water-deficit periods.”
Claim · model-written summary
Leaf photosynthesis, soluble protein, and RuBPCase activation and concentration recovered within 5 days after rewatering.
- Taxon
- Citrus sinensis [L.] OsbeckCitrus sinensist0
- Treatment
- rewateringe0
- Outcome
- leaf photosynthesis, soluble protein, and RuBPCase activation and concentratione0
- Direction
- recoverablee0
- Value
- 5 dayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Declines in leaf photosynthesis, soluble protein, and RuBPCase activation and concentration due to water deficit were, however, recoverable at 5 days after rewatering.”
t0“Valencia' Orange (Citrus sinensis [L.] Osbeck)”
The same questions in other papers
drought · molecular: metabolites · Citrus sinensis (sweet orange)Results agree
1 paper in the same direction as this paper
- no effect
drought · physiology: gas exchange · Citrus sinensis (sweet orange)Results agree
4 papers in the same direction as this paper
- negative
- negative
- negative
1 paper more in this group
See all 5 papers →drought · physiology: photosynthesis · Citrus sinensis (sweet orange)Results agree
4 papers in the same direction as this paper
- negative
- negative
- negative
1 paper more in this group
See all 5 papers →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.