Abstract
Sodium sulfite (Na 2 SO 3 ) decreased uptake from 1 m M sucrose by the parenchyma and by the veins of leaves of broadbean ( Vicia faba L. cv. Aguadulce). The decrease depended on the concentration of the pollutant and the duration of pretreatment. The inhibition was non‐competitive. Sulfite affected the transmembrane potential difference (PD) of the leaf tissues. The short‐term response obeyed an ‘all or nothing’ law. At 0.1 m M and above, sulfite led to a quick depolarization of one‐third of the initial potential after a lag phase of about 5 min; for concentrations lower than 0.1 m M , sulfite did not affect the potential. By contrast, the long‐term effect of Na 2 SO 3 on the transmembrane PD strongly depended on its concentration. After 2–12 h of pretreatmemt there was no effect at 10 μ M , a weak effect at 0.1 m M , and then increasing depolarization as the pollutant concentration increased. The inhibitory effect of Na 2 SO 3 on sucrose uptake is thus, at least partly, due to its effect on a component of the proton‐motive force. ΔΨ. However, the lack of correlation noticed with 0.1 m M Na 2 SO 3 between the effect on sucrose uptake and the long‐term effect on transmembrane PD suggests numerous sites of sulfite action.
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Claims 11
Claim · model-written summary
Sodium sulfite decreased sucrose uptake by broadbean leaf parenchyma and veins.
- Taxon
- broadbean
Vicia fabae0 - Material
- Vicia faba L. cv. Aguadulcee0
- Organ / stage
- parenchyma and by the veins of leavese0
- Treatment
- Sodium sulfitee0
- Outcome
- uptake from 1 m M sucrosee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sodium sulfite (Na 2 SO 3 ) decreased uptake from 1 m M sucrose by the parenchyma and by the veins of leaves of broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
The uptake decline depended on sulfite concentration and pretreatment duration.
- Taxon
- broadbeanVicia fabae1
- Treatment
- concentration of the pollutant and the duration of pretreatmente0
- Outcome
- The decreasee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease depended on the concentration of the pollutant and the duration of pretreatment”
e1“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
The inhibition of sucrose uptake was non-competitive.
- Taxon
- broadbeanVicia fabae1
- Outcome
- inhibition was non‐competitivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The inhibition was non‐competitive”
e1“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
Sulfite affected leaf transmembrane potential difference.
- Taxon
- broadbeanVicia fabae1
- Organ / stage
- leaf tissuese0
- Treatment
- Sulfitee0
- Outcome
- transmembrane potential difference (PD)e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sulfite affected the transmembrane potential difference (PD) of the leaf tissues”
e1“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
At at least 0.1 m M, sulfite caused rapid depolarization of one third of initial potential after about five minutes.
- Taxon
- broadbeanVicia fabae1
- Treatment
- 0.1 m M and above, sulfitee0
- Outcome
- potentiale0
- Direction
- depolarizatione0
- Value
- one‐thirde0
- Qualifier
- after a lag phase of about 5 mine0
- Comparator
- initial potentiale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 0.1 m M and above, sulfite led to a quick depolarization of one‐third of the initial potential after a lag phase of about 5 min”
e1“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
Below 0.1 m M, sulfite did not affect potential in the short term.
- Taxon
- broadbeanVicia fabae1
- Treatment
- concentrations lower than 0.1 m M , sulfitee0
- Outcome
- potentiale0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for concentrations lower than 0.1 m M , sulfite did not affect the potential”
e1“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
After 2–12 h, 10 μ M sulfite had no effect on potential difference.
- Taxon
- broadbeanVicia fabae2
- Treatment
- 10 μ Me0
- Outcome
- transmembrane PDe1
- Direction
- no effecte0
- Qualifier
- After 2–12 h of pretreatmemte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 2–12 h of pretreatmemt there was no effect at 10 μ M”
e1“long‐term effect of Na 2 SO 3 on the transmembrane PD”
e2“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
After 2–12 h, 0.1 m M sulfite had a weak effect on potential difference.
- Taxon
- broadbeanVicia fabae3
- Treatment
- 0.1 m Me0
- Outcome
- transmembrane PDe2
- Qualifier
- After 2–12 h of pretreatmemte1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a weak effect at 0.1 m M”
e1“After 2–12 h of pretreatmemt”
e2“long‐term effect of Na 2 SO 3 on the transmembrane PD”
e3“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
At higher concentrations, longer sulfite pretreatment caused increasing depolarization.
- Taxon
- broadbeanVicia fabae1
- Treatment
- pollutant concentratione0
- Outcome
- depolarizatione0
- Direction
- increasinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“then increasing depolarization as the pollutant concentration increased”
e1“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
The authors attribute part of sulfite inhibition of sucrose uptake to effects on proton-motive force.
- Taxon
- broadbeanVicia fabae1
- Treatment
- Na 2 SO 3e0
- Outcome
- sucrose uptakee0
- Qualifier
- at least partlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The inhibitory effect of Na 2 SO 3 on sucrose uptake is thus, at least partly, due to its effect on a component of the proton‐motive force. ΔΨ”
e1“broadbean ( Vicia faba L. cv. Aguadulce)”
Claim · model-written summary
The lack of correlation at 0.1 m M suggests multiple sulfite action sites.
- Taxon
- broadbeanVicia fabae1
- Treatment
- 0.1 m M Na 2 SO 3e0
- Outcome
- numerous sites of sulfite actione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the lack of correlation noticed with 0.1 m M Na 2 SO 3 between the effect on sucrose uptake and the long‐term effect on transmembrane PD suggests numerous sites of sulfite action”
e1“broadbean ( Vicia faba L. cv. Aguadulce)”