Abstract
Methods for the simultaneous measurement of vacuolar and cytoplasmic pH in plant tissues currently have significant limitations. This study demonstrates the usefulness of methyl difluoro alanine (F 2 ALA) and methyl trifluoro alanine (F 3 ALA) with in‐vivo 19 F NMR spectroscopy to measure vacuolar and cytoplasmic pH in maize root tissue. The pH dependence of the chemical shift of F 2 ALA and F 3 ALA is greater than either the commonly used 31 P NMR signal of inorganic phosphate or the 13 C NMR signals of trans‐aconitic acid, which is also found in some plant cells. F 2 ALA and F 3 ALA were also able to detect changes over a greater range of pH. When maize root tissue was incubated in the presence of 0.35 m m F 2 ALA or F 3 ALA, these accumulated to significant concentrations in two compartments of different pH with no significant effect on growth rate of root tips. The time course of accumulation and the pH of the two compartments were consistent with one being the cytoplasm and the other the vacuole. The chemical shift of both C 2 of trans‐aconitic acid and vacuolar F 3 ALA indicated that the mean vacuolar pH of maize root cells was 4.6 and that the pH gradient across the tonoplast membrane was about 2.8 units. Under a variety of conditions, there was considerable heterogeneity in the pH of the vacuoles in maize root tissue as indicated by the peak width of the signal from F 3 ALA. The significance of these values is discussed in terms of the bioenergetics of proton transport across the tonoplast membrane in vivo.
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Claims 11
Claim · model-written summary
F 2 ALA had greater pH dependence of chemical shift than comparison NMR signals.
- Outcome
- pH dependence of the chemical shift of F 2 ALAe0
- Direction
- greatere0
- Comparator
- 31 P NMR signal of inorganic phosphatee0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The pH dependence of the chemical shift of F 2 ALA and F 3 ALA is greater than either the commonly used 31 P NMR signal of inorganic phosphate or the 13 C NMR signals of trans‐aconitic acid”
t0“maize”
Claim · model-written summary
F 3 ALA had greater pH dependence of chemical shift than comparison NMR signals.
- Outcome
- pH dependence of the chemical shift of F 2 ALA and F 3 ALAe0
- Direction
- greatere0
- Comparator
- 13 C NMR signals of trans‐aconitic acide0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The pH dependence of the chemical shift of F 2 ALA and F 3 ALA is greater than either the commonly used 31 P NMR signal of inorganic phosphate or the 13 C NMR signals of trans‐aconitic acid”
t0“maize”
Claim · model-written summary
F 2 ALA detected changes over a greater pH range.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“F 2 ALA and F 3 ALA were also able to detect changes over a greater range of pH”
t0“maize”
Claim · model-written summary
F 3 ALA detected changes over a greater pH range.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“F 2 ALA and F 3 ALA were also able to detect changes over a greater range of pH”
t0“maize”
Claim · model-written summary
F 2 ALA accumulated in two maize root compartments at different pH.
- Organ / stage
- root tissuee0
- Treatment
- 0.35 m m F 2 ALAe0
- Outcome
- accumulated to significant concentrations in two compartments of different pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When maize root tissue was incubated in the presence of 0.35 m m F 2 ALA or F 3 ALA, these accumulated to significant concentrations in two compartments of different pH”
Claim · model-written summary
F 3 ALA accumulated in two maize root compartments at different pH.
- Organ / stage
- root tissuee0
- Treatment
- F 3 ALAe0
- Outcome
- accumulated to significant concentrations in two compartments of different pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When maize root tissue was incubated in the presence of 0.35 m m F 2 ALA or F 3 ALA, these accumulated to significant concentrations in two compartments of different pH”
Claim · model-written summary
The probes had no significant effect on maize root-tip growth rate.
- Treatment
- 0.35 m m F 2 ALA or F 3 ALAe0
- Outcome
- growth rate of root tipse0
- Direction
- no significant effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When maize root tissue was incubated in the presence of 0.35 m m F 2 ALA or F 3 ALA, these accumulated to significant concentrations in two compartments of different pH with no significant effect on growth rate of root tips”
Claim · model-written summary
The two measured compartments were consistent with cytoplasm and vacuole.
- Outcome
- one being the cytoplasm and the other the vacuolee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The time course of accumulation and the pH of the two compartments were consistent with one being the cytoplasm and the other the vacuole”
t0“maize”
Claim · model-written summary
Mean vacuolar pH of maize root cells was 4.6.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the mean vacuolar pH of maize root cells was 4.6”
Claim · model-written summary
The pH gradient across the tonoplast was about 2.8 units.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the pH gradient across the tonoplast membrane was about 2.8 units”
t0“maize”
Claim · model-written summary
Maize root vacuolar pH was heterogeneous under various conditions.
- Organ / stage
- root tissuee0
- Outcome
- heterogeneity in the pH of the vacuolese0
- Qualifier
- Under a variety of conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under a variety of conditions, there was considerable heterogeneity in the pH of the vacuoles in maize root tissue”
The same questions in other papers
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6 in the opposite direction
- positive
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3 papers more in this group
See all 7 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.