Abstract
Salinity (100 millimolar NaCl) was found to reduce photosynthetic capacity independent of stomatal closure in Phaseolus vulgaris. This reduction was shown to be a consequence of a reduction in the efficiency of ribulose-1,5-bisphosphate (RuBP) carboxylase (RuBPCase) rather than a reduction in the leaf content of photosynthetic machinery. In control plants, photosynthesis became RuBP-limited at approximately 1.75 moles RuBP per mole 2-carboxyarabinitol bisphosphate binding sites. Salinization caused the RuBP pool size to reach this limiting value for CO(2) fixation at much lower values of intercellular CO(2). Plants grown at low nitrogen and +/- NaCl became RuBP limited at similar RuBP pool sizes as the high nitrogen-grown plants. At limiting RuBP pool sizes and equal values of intercellular CO(2) photosynthetic capacity of salt-stressed plants was less than control plants. This effect of salinity on RuBPCase activity could not be explained by deactivation of the enzyme or inhibitor synthesis. Thus, salinity reduced photosynthetic capacity by reducing both the RuBP pool size by an effect on RuBP regeneration capacity and RuBPCase activity by an unknown mechanism when RuBP was limiting.
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Claims 8
Claim · model-written summary
Salinity reduced photosynthetic capacity independently of stomatal closure.
- Taxon
- Phaseolus vulgaris
Phaseolus vulgarise0 - Treatment
- Salinity (100 millimolar NaCl)e0
- Outcome
- photosynthetic capacitye0
- Direction
- reducee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salinity (100 millimolar NaCl) was found to reduce photosynthetic capacity independent of stomatal closure in Phaseolus vulgaris.”
Claim · model-written summary
Salinity reduced RuBPCase efficiency.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Gene
- ribulose-1,5-bisphosphate (RuBP) carboxylase (RuBPCase)e0
- Outcome
- efficiencye0
- Direction
- reductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This reduction was shown to be a consequence of a reduction in the efficiency of ribulose-1,5-bisphosphate (RuBP) carboxylase (RuBPCase) rather than a reduction in the leaf content of photosynthetic machinery.”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Control photosynthesis became RuBP limited at approximately 1.75 moles per mole binding sites.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Outcome
- photosynthesis became RuBP-limitede0
- Value
- 1.75 moles RuBP per mole 2-carboxyarabinitol bisphosphate binding sitese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In control plants, photosynthesis became RuBP-limited at approximately 1.75 moles RuBP per mole 2-carboxyarabinitol bisphosphate binding sites.”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Salinization brought RuBP to its limiting pool size at much lower intercellular CO2.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- Salinizatione0
- Outcome
- intercellular CO(2)e0
- Direction
- much lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salinization caused the RuBP pool size to reach this limiting value for CO(2) fixation at much lower values of intercellular CO(2).”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Low and high nitrogen plants became RuBP limited at similar pool sizes.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- low nitrogen and +/- NaCle0
- Outcome
- RuBP pool sizese0
- Direction
- similare0
- Comparator
- high nitrogen-grown plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants grown at low nitrogen and +/- NaCl became RuBP limited at similar RuBP pool sizes as the high nitrogen-grown plants.”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
At limiting RuBP and equal intercellular CO2, salt-stressed plants had lower photosynthetic capacity than controls.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- salt-stressed plantse0
- Outcome
- photosynthetic capacitye0
- Direction
- less thane0
- Qualifier
- At limiting RuBP pool sizes and equal values of intercellular CO(2)e0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At limiting RuBP pool sizes and equal values of intercellular CO(2) photosynthetic capacity of salt-stressed plants was less than control plants.”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Salinity reduced RuBP pool size through reduced regeneration capacity.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- salinitye0
- Outcome
- RuBP pool sizee0
- Direction
- reducinge0
- Qualifier
- RuBP regeneration capacitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“salinity reduced photosynthetic capacity by reducing both the RuBP pool size by an effect on RuBP regeneration capacity and RuBPCase activity by an unknown mechanism when RuBP was limiting.”
t0“Phaseolus vulgaris L.”
Claim · model-written summary
Salinity reduced RuBPCase activity through an unknown mechanism when RuBP was limiting.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarist0
- Treatment
- salinitye0
- Gene
- RuBPCasee0
- Outcome
- RuBPCase activitye0
- Direction
- reducinge0
- Qualifier
- unknown mechanism when RuBP was limitinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“salinity reduced photosynthetic capacity by reducing both the RuBP pool size by an effect on RuBP regeneration capacity and RuBPCase activity by an unknown mechanism when RuBP was limiting.”
t0“Phaseolus vulgaris L.”
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See all 23 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.