Abstract
The mechanistic basis for cation amelioration of Al rhizotoxicity in soybean was investigated through a series of studies comparing protective effects of Ca and Mg against Al inhibition of root elongation in a background 0.8 mM CaSO4 solution (pH 4.3). A modified Gouy-Chapman-Stern model was used to evaluate the effect of cations on electrical potential and Al3+ activity at root plasma membrane surfaces. Activities of Al3+ up to 4.6 microM in the background solution inhibited soybean tap root elongation by more than 80%. There was little or no response in root elongation when Ca and Mg were added to background solutions in the absence of AL: When added to Al-toxic solutions in the micromolar concentration range, Mg was 100-fold more effective than Ca in alleviating Al toxicity, whereas both cations were equally effective when added in the millimolar concentration range. The protective effect of micromolar additions of Mg on root elongation was specific for Al and it failed to alleviate La rhizotoxicity. In contrast to wheat, Mg amelioration of Al toxicity to soybean root elongation at low Mg concentration could not be explained by changes in potential and Al3+ activity at the root plasma membrane surfaces as predicted by a Gouy-Chapman-Stern model. These results suggest that Mg is not acting as an indifferent cation when present at low concentration and implies the involvement of a mechanism other than pure electrostatic effects at the root surface.
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Claims 7
Claim · model-written summary
Al3+ activities up to 4.6 microM inhibited soybean tap root elongation by more than 80%.
- Taxon
- soybean
Glycine maxe1 - Treatment
- Activities of Al3+ up to 4.6 microMe1
- Outcome
- tap root elongatione1
- Direction
- inhibitede1
- Value
- more than 80%e1
- Comparator
- background solutione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Activities of Al3+ up to 4.6 microM in the background solution inhibited soybean tap root elongation by more than 80%”
Claim · model-written summary
Ca and Mg added without Al had little or no effect on soybean root elongation.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Ca and Mge2
- Outcome
- root elongatione2
- Direction
- little or no responsee2
- Comparator
- background solutionse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alleviating Aluminum Rhizotoxicity in Soybean”
e2“There was little or no response in root elongation when Ca and Mg were added to background solutions in the absence of AL”
Claim · model-written summary
At micromolar concentrations, Mg was 100-fold more effective than Ca in alleviating Al toxicity in soybean.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- Mge3
- Outcome
- alleviating Al toxicitye3
- Direction
- more effectivee3
- Value
- 100-folde3
- Qualifier
- micromolar concentration rangee3
- Comparator
- Cae3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alleviating Aluminum Rhizotoxicity in Soybean”
e3“When added to Al-toxic solutions in the micromolar concentration range, Mg was 100-fold more effective than Ca in alleviating Al toxicity”
Claim · model-written summary
At millimolar concentrations, Mg and Ca were equally effective in alleviating Al toxicity.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- added in the millimolar concentration rangee4
- Outcome
- alleviating Al toxicitye3
- Direction
- equally effectivee4
- Comparator
- Cae3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alleviating Aluminum Rhizotoxicity in Soybean”
e3“When added to Al-toxic solutions in the micromolar concentration range, Mg was 100-fold more effective than Ca in alleviating Al toxicity”
e4“both cations were equally effective when added in the millimolar concentration range”
Claim · model-written summary
The protective effect of micromolar Mg was specific for Al and did not alleviate La rhizotoxicity.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- micromolar additions of Mge5
- Outcome
- La rhizotoxicitye5
- Direction
- failed to alleviatee5
- Qualifier
- specific for Ale5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alleviating Aluminum Rhizotoxicity in Soybean”
e5“The protective effect of micromolar additions of Mg on root elongation was specific for Al and it failed to alleviate La rhizotoxicity”
Claim · model-written summary
Mg amelioration of Al toxicity at low Mg concentration could not be explained by changes in surface potential and Al3+ activity predicted by the Gouy-Chapman-Stern model.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- low Mg concentratione6
- Compound
- Al3+ activitye6
- Outcome
- Mg amelioration of Al toxicitye6
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alleviating Aluminum Rhizotoxicity in Soybean”
e6“In contrast to wheat, Mg amelioration of Al toxicity to soybean root elongation at low Mg concentration could not be explained by changes in potential and Al3+ activity at the root plasma membrane surfaces as predicted by a Gouy-Chapman-Stern model”
Claim · model-written summary
Mg is not acting as an indifferent cation at low concentration, implying a mechanism beyond electrostatic effects.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- Mg is not acting as an indifferent catione7
- Qualifier
- when present at low concentratione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alleviating Aluminum Rhizotoxicity in Soybean”
e7“These results suggest that Mg is not acting as an indifferent cation when present at low concentration and implies the involvement of a mechanism other than pure electrostatic effects at the root surface”
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See all 29 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.