Abstract
One of the most important functions of the plant hormone abscisic acid (ABA) is to induce stomatal closure by reducing the turgor of guard cells under water deficit. Under environmental stresses, hydrogen peroxide (H(2)O(2)), an active oxygen species, is widely generated in many biological systems. Here, using an epidermal strip bioassay and laser-scanning confocal microscopy, we provide evidence that H(2)O(2) may function as an intermediate in ABA signaling in Vicia faba guard cells. H(2)O(2) inhibited induced closure of stomata, and this effect was reversed by ascorbic acid at concentrations lower than 10(-5) M. Further, ABA-induced stomatal closure also was abolished partly by addition of exogenous catalase (CAT) and diphenylene iodonium (DPI), which are an H(2)O(2) scavenger and an NADPH oxidase inhibitor, respectively. Time course experiments of single-cell assays based on the fluorescent probe dichlorofluorescein showed that the generation of H(2)O(2) was dependent on ABA concentration and an increase in the fluorescence intensity of the chloroplast occurred significantly earlier than within the other regions of guard cells. The ABA-induced change in fluorescence intensity in guard cells was abolished by the application of CAT and DPI. In addition, ABA microinjected into guard cells markedly induced H(2)O(2) production, which preceded stomatal closure. These effects were abolished by CAT or DPI micro-injection. Our results suggest that guard cells treated with ABA may close the stomata via a pathway with H(2)O(2) production involved, and H(2)O(2) may be an intermediate in ABA signaling.
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Claims 12
Claim · model-written summary
Hydrogen peroxide inhibited induced stomatal closure.
- Taxon
- Vicia faba
Vicia fabat0 - Treatment
- H(2)O(2)e0
- Outcome
- induced closure of stomatae0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“H(2)O(2) inhibited induced closure of stomata”
Claim · model-written summary
Ascorbic acid below 10(-5) M reversed the hydrogen peroxide effect.
- Taxon
- Vicia fabaVicia fabat0
- Treatment
- ascorbic acid at concentrations lower than 10(-5) Me0
- Outcome
- this effecte0
- Direction
- reversede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“this effect was reversed by ascorbic acid at concentrations lower than 10(-5) M”
Claim · model-written summary
Catalase partly abolished ABA-induced stomatal closure.
- Taxon
- Vicia fabaVicia fabat0
- Treatment
- exogenous catalase (CAT)e0
- Outcome
- ABA-induced stomatal closuree0
- Direction
- abolished partlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“ABA-induced stomatal closure also was abolished partly by addition of exogenous catalase (CAT) and diphenylene iodonium (DPI)”
Claim · model-written summary
DPI partly abolished ABA-induced stomatal closure.
- Taxon
- Vicia fabaVicia fabat0
- Treatment
- diphenylene iodonium (DPI)e0
- Outcome
- ABA-induced stomatal closuree0
- Direction
- abolished partlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“ABA-induced stomatal closure also was abolished partly by addition of exogenous catalase (CAT) and diphenylene iodonium (DPI)”
Claim · model-written summary
Hydrogen peroxide generation depended on ABA concentration.
- Taxon
- Vicia fabaVicia fabat0
- Compound
- ABAe0
- Outcome
- generation of H(2)O(2)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“the generation of H(2)O(2) was dependent on ABA concentration”
Claim · model-written summary
Chloroplast fluorescence rose earlier than fluorescence elsewhere in guard cells.
- Taxon
- Vicia fabaVicia fabat0
- Outcome
- fluorescence intensity of the chloroplaste0
- Direction
- increasee0
- Comparator
- other regions of guard cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“an increase in the fluorescence intensity of the chloroplast occurred significantly earlier than within the other regions of guard cells”
Claim · model-written summary
CAT abolished the ABA-induced change in guard-cell fluorescence.
- Taxon
- Vicia fabaVicia fabat0
- Treatment
- CATe0
- Outcome
- ABA-induced change in fluorescence intensity in guard cellse0
- Direction
- abolishede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“The ABA-induced change in fluorescence intensity in guard cells was abolished by the application of CAT and DPI.”
Claim · model-written summary
DPI abolished the ABA-induced change in guard-cell fluorescence.
- Taxon
- Vicia fabaVicia fabat0
- Treatment
- DPIe0
- Outcome
- ABA-induced change in fluorescence intensity in guard cellse0
- Direction
- abolishede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“The ABA-induced change in fluorescence intensity in guard cells was abolished by the application of CAT and DPI.”
Claim · model-written summary
Microinjected ABA markedly induced hydrogen peroxide production before stomatal closure.
- Taxon
- Vicia fabaVicia fabat0
- Treatment
- ABA microinjected into guard cellse0
- Outcome
- H(2)O(2) productione0
- Direction
- inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“ABA microinjected into guard cells markedly induced H(2)O(2) production, which preceded stomatal closure.”
Claim · model-written summary
CAT microinjection abolished the effects of ABA microinjection.
- Taxon
- Vicia fabaVicia fabat0
- Treatment
- CATe0
- Outcome
- These effectse0
- Direction
- abolishede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“These effects were abolished by CAT or DPI micro-injection.”
Claim · model-written summary
DPI microinjection abolished the effects of ABA microinjection.
- Taxon
- Vicia fabaVicia fabat0
- Treatment
- DPIe0
- Outcome
- These effectse0
- Direction
- abolishede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“These effects were abolished by CAT or DPI micro-injection.”
Claim · model-written summary
The authors propose hydrogen peroxide as an intermediate in ABA-induced stomatal closure.
- Taxon
- Vicia fabaVicia fabat0
- Compound
- H(2)O(2)e0
- Outcome
- close the stomatae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Vicia faba”
e0“guard cells treated with ABA may close the stomata via a pathway with H(2)O(2) production involved, and H(2)O(2) may be an intermediate in ABA signaling.”
The same questions in other papers
dibenziodolium · physiology: gas exchange · Vicia faba (faba bean)Results differ
2 papers in the same direction as this paper · 2 in the opposite direction
- positive
- positive
- negative
1 paper more in this group
See all 5 papers →hydrogen peroxide · physiology: gas exchange · Vicia faba (faba bean)Positive and negative results
2 papers in the same direction as this paper · 3 in the opposite direction
- no effect
- positive
- positive
2 papers more in this group
See all 6 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.