Abstract
Root elongation, hematoxylin staining, and changes in the ultrastructure of root-tip cells of an Al-tolerant maize variety (Zea mays L. C 525 M) exposed to nutrient solutions with 20 &mgr;M Al (2.1 &mgr;M Al3+ activity) for 0, 4, and 24 h were investigated in relation to the subcellular distribution of Al using scanning transmission electron microscopy and energy-dispersive x-ray microanalysis on samples fixed by different methods. Inhibition of root-elongation rates, hematoxylin staining, cell wall thickening, and disturbance of the distribution of pyroantimoniate-stainable cations, mainly Ca, was observed only after 4 and not after 24 h of exposure to Al. The occurrence of these transient, toxic Al effects on root elongation and in cell walls was accompanied by the presence of solid Al-P deposits in the walls. Whereas no Al was detectable in cell walls after 24 h, an increase of vacuolar Al was observed after 4 h of exposure. After 24 h, a higher amount of electron-dense deposits containing Al and P or Si was observed in the vacuoles. These results indicate that in this tropical maize variety, tolerance mechanisms that cause a change in apoplastic Al must be active. Our data support the hypothesis that in Al-tolerant plants, Al can rapidly cross the plasma membrane; these data clearly contradict the former conclusions that Al mainly accumulates in the apoplast and enters the symplast only after severe cell damage has occurred.
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Claims 10
Claim · model-written summary
Root elongation of the aluminum-tolerant maize variety was inhibited after 4 hours of aluminum exposure but not after 24 hours.
- Material
- Zea mays L. C 525 Me0
- Treatment
- 20 &mgr;M Ale0
- Outcome
- root-elongation ratese1
- Direction
- Inhibitione1
- Qualifier
- only after 4 and not after 24 he1
- Comparator
- 24 he1
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al-tolerant maize variety (Zea mays L. C 525 M) exposed to nutrient solutions with 20 &mgr;M Al (2.1 &mgr;M Al3+ activity) for 0, 4, and 24 h”
e1“Inhibition of root-elongation rates, hematoxylin staining, cell wall thickening, and disturbance of the distribution of pyroantimoniate-stainable cations, mainly Ca, was observed only after 4 and not after 24 h of exposure to Al”
Claim · model-written summary
Hematoxylin staining appeared only after 4 hours of aluminum exposure in the maize roots.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al-tolerant maize variety”
e1“hematoxylin staining, cell wall thickening, and disturbance of the distribution of pyroantimoniate-stainable cations, mainly Ca, was observed only after 4 and not after 24 h of exposure to Al”
Claim · model-written summary
Maize root cell walls thickened only after 4 hours of aluminum exposure.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al-tolerant maize variety”
e1“cell wall thickening, and disturbance of the distribution of pyroantimoniate-stainable cations, mainly Ca, was observed only after 4 and not after 24 h of exposure to Al”
Claim · model-written summary
Distribution of pyroantimoniate-stainable cations in maize roots was disturbed only after 4 hours of aluminum exposure.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al-tolerant maize variety”
e1“disturbance of the distribution of pyroantimoniate-stainable cations, mainly Ca, was observed only after 4 and not after 24 h of exposure to Al”
Claim · model-written summary
Solid Al-P deposits accompanied transient toxic effects in maize root cell walls.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al-tolerant maize variety”
e1“The occurrence of these transient, toxic Al effects on root elongation and in cell walls was accompanied by the presence of solid Al-P deposits in the walls”
Claim · model-written summary
No aluminum was detectable in maize root cell walls after 24 hours.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al-tolerant maize variety”
e1“no Al was detectable in cell walls after 24 h”
Claim · model-written summary
Vacuolar aluminum increased after 4 hours of exposure in maize roots.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al-tolerant maize variety”
e1“an increase of vacuolar Al was observed after 4 h of exposure”
Claim · model-written summary
More vacuolar deposits containing aluminum and phosphorus or silicon were observed after 24 hours in maize roots.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Al-tolerant maize variety”
e1“After 24 h, a higher amount of electron-dense deposits containing Al and P or Si was observed in the vacuoles”
Claim · model-written summary
The authors infer active tolerance mechanisms changing apoplastic aluminum in this maize variety.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in this tropical maize variety, tolerance mechanisms that cause a change in apoplastic Al must be active”
Claim · model-written summary
The data support rapid crossing of the plasma membrane by aluminum in aluminum-tolerant plants.
- Taxon
- plantsViridiplantaee0
- Outcome
- Al can rapidly cross the plasma membranee0
- Qualifier
- Al-tolerante0
Not reportedDirection
Verbatim
e0“in Al-tolerant plants, Al can rapidly cross the plasma membrane”
The same questions in other papers
aluminium atom · growth · Zea mays (maize)Results differ
34 papers in the same direction as this paper · 7 in the opposite direction
- positive
- negative
- negative
38 papers more in this group
See all 42 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.