Abstract
Spinach (Spinacia oleracea) plants were subjected to salt stress by adding NaCl to the nutrient solution in increments of 25 millimolar per day to a final concentration of 200 millimolar. Plants were harvested 3 weeks after starting NaCl treatment. Fresh and dry weight of both shoots and roots was decreased more than 50% compared to control plants but the salt-stressed plants appeared healthy and were still actively growing. The salt-stressed plants had much thicker leaves. The salt-treated plants osmotically adjusted to maintain leaf turgor. Leaf K(+) was decreased but Na(+) and Cl(-) were greatly increased.The potential photosynthetic capacity of the leaves was measured at saturating CO(2) to overcome any stomatal limitation. Photosynthesis of salt-stressed plants varied only by about 10% from the controls when expressed on a leaf area or chlorophyll basis. The yield of variable chlorophyll a fluorescence from leaves was not affected by salt stress. Stomatal conductance decreased 70% in response to salt treatment.Uncoupled rates of electron transport by isolated intact chloroplasts and by thylakoids were only 10 to 20% below those for control plants. CO(2)-dependent O(2) evolution was decreased by 20% in chloroplasts isolated from salt-stressed plants. The concentration of K(+) in the chloroplast decreased by 50% in the salt-stressed plants, Na(+) increased by 70%, and Cl(-) increased by less than 20% despite large increases in leaf Na(+) and Cl(-).It is concluded that, for spinach, salt stress does not result in any major decrease in the photosynthetic potential of the leaf. Actual photosynthesis by the plant may be reduced by other factors such as decreased stomatal conductance and decreased leaf area. Effective compartmentation of ions within the cell may prevent the accumulation of inhibitory levels of Na(+) and Cl(-) in the chloroplast.
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Claims 16
Claim · model-written summary
Salt stress decreased shoot and root fresh and dry weight by more than 50%.
- Taxon
- Spinach
Spinacia oleraceat0 - Treatment
- salt stress by adding NaCle1
- Outcome
- Fresh and dry weight of both shoots and rootse0
- Direction
- decreasede0
- Value
- more than 50%e0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fresh and dry weight of both shoots and roots was decreased more than 50% compared to control plants”
e1“salt stress by adding NaCl”
t0“Spinach”
Claim · model-written summary
Salt-stressed leaves were thicker.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- much thicker leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The salt-stressed plants had much thicker leaves”
t0“Spinach”
Claim · model-written summary
Salt-treated plants osmotically adjusted to maintain turgor.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- osmotically adjusted to maintain leaf turgore0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The salt-treated plants osmotically adjusted to maintain leaf turgor”
t0“Spinach”
Claim · model-written summary
Leaf potassium decreased.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- Leaf K(+)e0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf K(+) was decreased”
t0“Spinach”
Claim · model-written summary
Leaf sodium and chloride greatly increased.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- Na(+) and Cl(-)e0
- Direction
- greatly increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Na(+) and Cl(-) were greatly increased”
t0“Spinach”
Claim · model-written summary
Photosynthesis differed by about 10% from controls on area or chlorophyll bases.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- Photosynthesise0
- Value
- about 10%e0
- Comparator
- controlse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Photosynthesis of salt-stressed plants varied only by about 10% from the controls when expressed on a leaf area or chlorophyll basis”
t0“Spinach”
Claim · model-written summary
Variable chlorophyll fluorescence yield was not affected.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- yield of variable chlorophyll a fluorescence from leavese0
- Direction
- not affectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The yield of variable chlorophyll a fluorescence from leaves was not affected by salt stress”
t0“Spinach”
Claim · model-written summary
Stomatal conductance decreased 70%.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- Stomatal conductancee0
- Direction
- decreasede0
- Value
- 70%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stomatal conductance decreased 70% in response to salt treatment”
t0“Spinach”
Claim · model-written summary
Electron transport rates in chloroplasts and thylakoids were 10 to 20% below controls.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- Uncoupled rates of electron transport by isolated intact chloroplasts and by thylakoidse0
- Direction
- belowe0
- Value
- 10 to 20%e0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Uncoupled rates of electron transport by isolated intact chloroplasts and by thylakoids were only 10 to 20% below those for control plants”
t0“Spinach”
Claim · model-written summary
Chloroplast CO2 dependent oxygen evolution decreased 20%.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- CO(2)-dependent O(2) evolutione0
- Direction
- decreasede0
- Value
- 20%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO(2)-dependent O(2) evolution was decreased by 20% in chloroplasts isolated from salt-stressed plants”
t0“Spinach”
Claim · model-written summary
Chloroplast potassium decreased 50%.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- concentration of K(+) in the chloroplaste0
- Direction
- decreasede0
- Value
- 50%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The concentration of K(+) in the chloroplast decreased by 50% in the salt-stressed plants”
t0“Spinach”
Claim · model-written summary
Chloroplast sodium increased 70%.
- Taxon
- SpinachSpinacia oleraceat0
- Organ / stage
- chloroplaste1
- Outcome
- Na(+)e0
- Direction
- increasede0
- Value
- 70%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Na(+) increased by 70%”
e1“K(+) in the chloroplast”
t0“Spinach”
Claim · model-written summary
Chloroplast chloride increased by less than 20%.
- Taxon
- SpinachSpinacia oleraceat0
- Organ / stage
- chloroplaste1
- Outcome
- Cl(-)e0
- Direction
- increasede0
- Value
- less than 20%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cl(-) increased by less than 20%”
e1“K(+) in the chloroplast”
t0“Spinach”
Claim · model-written summary
Authors conclude leaf photosynthetic potential was not greatly reduced.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- photosynthetic potential of the leafe0
- Direction
- does not result in any major decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“salt stress does not result in any major decrease in the photosynthetic potential of the leaf”
t0“Spinach”
Claim · model-written summary
Authors suggest stomatal conductance and leaf area may reduce actual photosynthesis.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- Actual photosynthesise0
- Qualifier
- decreased stomatal conductance and decreased leaf areae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Actual photosynthesis by the plant may be reduced by other factors such as decreased stomatal conductance and decreased leaf area”
t0“Spinach”
Claim · model-written summary
Authors suggest ion compartmentation may prevent inhibitory ion accumulation in chloroplasts.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- accumulation of inhibitory levels of Na(+) and Cl(-) in the chloroplaste0
- Qualifier
- Effective compartmentation of ions within the celle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Effective compartmentation of ions within the cell may prevent the accumulation of inhibitory levels of Na(+) and Cl(-) in the chloroplast”
t0“Spinach”
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See all 34 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.