Abstract
Effects of indoleacetic acid (IAA) and of turgor changes on the apparent molecular mass (M(r)) distributions of cell wall matrix polysaccharides from etiolated pea (Pisum sativum L.) epicotyl segments were determined by gel filtration chromatography. IAA causes a two- to threefold decline in the peak M(r) of xyloglucan, relative to minus-auxin controls, to occur within 0.5 hour. IAA causes an even larger decrease in the peak M(r) concurrently biosynthesized xyloglucan, as determined by [(3)H]fucose labeling, but this effect begins only after 1 hour. In contrast, IAA does not appreciably affect the M(r) distributions of pectic polyuronides or hemicellulosic arabinose/galactose polysaccharides within 1.5 hours. However, after epicotyl segments are cut, their peak polyuronide M(r) increases and later decreases, possibly as part of a wound response. Xyloglucan also undergoes IAA-independent changes in its M(r) distribution after cutting segments. In addition, the peak M(r) of newly deposited xyloglucan increases from about 9 kilodaltons shortly after deposition to about 30 kilodaltons within 0.5 hour. This may represent a process of integration into the cell wall. A step increase in turgor causes the peak M(r) of previously deposited xyloglucan (but not of the other major polymers) to increase about 10-fold within 0.5 hour, returning to its initial value by 1.5 hours. This upshift may comprise a feedback mechanism that decreases wall extensibility when the rate of wall extension suddenly increases. IAA-induced reduction of xyloglucan M(r) might cause wall loosening that leads to cell enlargement, as has been suggested previously, but the lack of a simple relation between xyloglucan M(r) and elongation rate indicates that loosening must also involve other wall factors, one of which might be the deposition of new xyloglucan of much smaller size. Although the M(r) shifts in polyuronides may represent changes in noncovalent association, and for xyloglucan this cannot be completely excluded, xyloglucan seems to participate in a dynamic process that can both decrease and increase its chain length, possible mechanisms for which are suggested.
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Claims 10
Claim · model-written summary
IAA lowered peak xyloglucan molecular mass two- to threefold within 0.5 hour.
- Taxon
- pea
Lathyrus oleraceuse0 - Treatment
- IAAe0
- Outcome
- peak M(r) of xyloglucane0
- Direction
- declinee0
- Value
- two- to threefolde0
- Qualifier
- within 0.5 houre0
- Comparator
- minus-auxin controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IAA causes a two- to threefold decline in the peak M(r) of xyloglucan, relative to minus-auxin controls, to occur within 0.5 hour”
t0“Pea”
Claim · model-written summary
IAA caused a larger decrease in newly synthesized xyloglucan molecular mass, beginning after 1 hour.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- IAAe0
- Outcome
- peak M(r) concurrently biosynthesized xyloglucane0
- Direction
- decreasee0
- Qualifier
- after 1 houre0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IAA causes an even larger decrease in the peak M(r) concurrently biosynthesized xyloglucan, as determined by [(3)H]fucose labeling, but this effect begins only after 1 hour”
t0“Pea”
Claim · model-written summary
IAA did not appreciably alter pectic polyuronide molecular mass distributions within 1.5 hours.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- IAAe0
- Outcome
- M(r) distributions of pectic polyuronidese0
- Direction
- does not appreciably affecte0
- Qualifier
- within 1.5 hourse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IAA does not appreciably affect the M(r) distributions of pectic polyuronides or hemicellulosic arabinose/galactose polysaccharides within 1.5 hours”
t0“Pea”
Claim · model-written summary
IAA did not appreciably alter hemicellulosic arabinose/galactose polysaccharide molecular mass distributions within 1.5 hours.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- IAAe0
- Outcome
- M(r) distributions of pectic polyuronides or hemicellulosic arabinose/galactose polysaccharidese0
- Direction
- does not appreciably affecte0
- Qualifier
- within 1.5 hourse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IAA does not appreciably affect the M(r) distributions of pectic polyuronides or hemicellulosic arabinose/galactose polysaccharides within 1.5 hours”
t0“Pea”
Claim · model-written summary
After cutting, peak polyuronide molecular mass first increased and later decreased.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- epicotyl segments are cute0
- Outcome
- peak polyuronide M(r)e0
- Direction
- increases and later decreasese0
- Qualifier
- possibly as part of a wound responsee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“after epicotyl segments are cut, their peak polyuronide M(r) increases and later decreases, possibly as part of a wound response”
t0“Pea”
Claim · model-written summary
Cutting also produced IAA-independent changes in xyloglucan molecular mass distribution.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- cutting segmentse0
- Outcome
- M(r) distributione0
- Qualifier
- IAA-independente0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Xyloglucan also undergoes IAA-independent changes in its M(r) distribution after cutting segments”
t0“Pea”
Claim · model-written summary
Peak molecular mass of newly deposited xyloglucan rose from about 9 to about 30 kilodaltons within 0.5 hour.
- Taxon
- peaLathyrus oleraceuse0
- Outcome
- peak M(r) of newly deposited xyloglucane0
- Direction
- increasese0
- Value
- about 30 kilodaltonse0
- Qualifier
- about 9 kilodaltons shortly after depositione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the peak M(r) of newly deposited xyloglucan increases from about 9 kilodaltons shortly after deposition to about 30 kilodaltons within 0.5 hour”
t0“Pea”
Claim · model-written summary
A turgor step increased peak molecular mass of previously deposited xyloglucan about tenfold within 0.5 hour, with recovery by 1.5 hours.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- step increase in turgore0
- Outcome
- peak M(r) of previously deposited xyloglucane0
- Direction
- increasee0
- Value
- about 10-folde0
- Qualifier
- returning to its initial value by 1.5 hourse0
- Comparator
- initial valuee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A step increase in turgor causes the peak M(r) of previously deposited xyloglucan (but not of the other major polymers) to increase about 10-fold within 0.5 hour, returning to its initial value by 1.5 hours”
t0“Pea”
Claim · model-written summary
A turgor step did not increase molecular mass of the other major polymers.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- step increase in turgore0
- Outcome
- other major polymerse0
- Direction
- no_changeinferrede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A step increase in turgor causes the peak M(r) of previously deposited xyloglucan (but not of the other major polymers) to increase about 10-fold within 0.5 hour”
t0“Pea”
Claim · model-written summary
The xyloglucan molecular mass and elongation rate lacked a simple relationship.
- Taxon
- peaLathyrus oleraceust0
- Compound
- xyloglucane0
- Outcome
- elongation ratee0
- Qualifier
- lack of a simple relation between xyloglucan M(r) and elongation ratee0
Not reportedOrgan / stageDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the lack of a simple relation between xyloglucan M(r) and elongation rate indicates that loosening must also involve other wall factors”
t0“Pea”
The same questions in other papers
indole-3-acetic acid · molecular: metabolites · Lathyrus oleraceus (pea)Positive and negative results
6 papers in the same direction as this paper · 12 in the opposite direction
- positive
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15 papers more in this group
See all 19 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.