Abstract
Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.), with the relative promotion being far greater in dwarf plants. In dwarf seedlings, solutions of IAA (between 10-4 and 10-3 M), when continuously applied to the uppermost two internodes via a cotton wick, increased whole-stem growth by at least 6-fold over the first 24 h. The magnitude of growth promotion correlated with the applied IAA concentration from 10-6 to 10-3 M, particularly over the first 6 h of application. IAA applied only to the apical bud or the uppermost internode of the seedling stimulated a biphasic growth response in the uppermost internode and the immediately lower internode, with the response in the latter being greatly delayed. This demonstrates that exogenous IAA effectively promotes growth as it is transported through intact stems. IAA withdrawal and reapplication at various times enabled the separation of the initial growth response (IGR) and prolonged growth response (PGR) induced by auxin. The IGR was inducible by at least 1 order of magnitude lower IAA concentrations than the PGR, suggesting that the process underlying the IGR is more sensitive to auxin induction. In contrast to the magnitude of the IAA effect in dwarf seedlings, applied IAA only doubled the growth in tall seedlings. These results suggest that endogenous IAA is more growth limiting in dwarf plants than in tall plants, and that auxin promotes stem elongation in the intact plant probably by the same mechanism of action as in isolated stem segments. However, since dwarf plants to which IAA was applied failed to reach the growth rate of tall plants, auxin cannot be the only limiting factor for stem growth in peas.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 9
Claim · model-written summary
Continuous IAA application increased whole-stem growth of dwarf pea seedlings by at least 6-fold over 24 h.
- Taxon
- Pisum sativum
Lathyrus oleraceuse0 - Material
- cv Progress No. 9e0
- Organ / stage
- uppermost two internodese1
- Treatment
- solutions of IAA (between 10-4 and 10-3 M)e1
- Outcome
- whole-stem growthe1
- Direction
- increasede1
- Value
- at least 6-folde1
- Setting
- intact light-grown seedlingse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e1“In dwarf seedlings, solutions of IAA (between 10-4 and 10-3 M), when continuously applied to the uppermost two internodes via a cotton wick, increased whole-stem growth by at least 6-fold over the first 24 h”
Claim · model-written summary
Applied IAA only doubled stem growth in tall pea seedlings, a smaller effect than in dwarf seedlings.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Material
- cv Alaskae0
- Treatment
- applied IAAe2
- Outcome
- growthe2
- Direction
- doublede2
- Comparator
- dwarf seedlingse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e2“In contrast to the magnitude of the IAA effect in dwarf seedlings, applied IAA only doubled the growth in tall seedlings”
Claim · model-written summary
The initial growth response was inducible by at least 1 order of magnitude lower IAA concentrations than the prolonged growth response.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Outcome
- IGRe3
- Value
- 1 order of magnitudee3
- Comparator
- PGRe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e3“The IGR was inducible by at least 1 order of magnitude lower IAA concentrations than the PGR”
Claim · model-written summary
IAA applied only to the apical bud or uppermost internode stimulated a biphasic growth response, with the response in the lower internode greatly delayed.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Organ / stage
- uppermost internode and the immediately lower internodee4
- Treatment
- IAA applied only to the apical bud or the uppermost internodee4
- Outcome
- biphasic growth responsee4
- Direction
- stimulatede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e4“IAA applied only to the apical bud or the uppermost internode of the seedling stimulated a biphasic growth response in the uppermost internode and the immediately lower internode, with the response in the latter being greatly delayed”
Claim · model-written summary
Exogenous IAA promoted growth as it was transported through intact stems.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Treatment
- exogenous IAAe5
- Outcome
- growthe5
- Direction
- promotese5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e5“This demonstrates that exogenous IAA effectively promotes growth as it is transported through intact stems”
Claim · model-written summary
Endogenous IAA is suggested to limit growth more in dwarf plants than in tall plants.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Compound
- endogenous IAAe6
- Outcome
- growth limitinge6
- Direction
- more growth limitinge6
- Comparator
- tall plantse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e6“These results suggest that endogenous IAA is more growth limiting in dwarf plants than in tall plants”
Claim · model-written summary
Dwarf pea plants treated with IAA failed to reach the growth rate of tall plants.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Outcome
- growth ratee7
- Direction
- failed to reache7
- Comparator
- tall plantse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e7“since dwarf plants to which IAA was applied failed to reach the growth rate of tall plants”
Claim · model-written summary
Auxin cannot be the only limiting factor for stem growth in peas.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Outcome
- stem growthe1
- Qualifier
- auxin cannot be the only limiting factore1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e1“auxin cannot be the only limiting factor for stem growth in peas”
Claim · model-written summary
Auxin probably promotes stem elongation by the same mechanism as in isolated stem segments.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Outcome
- stem elongatione1
- Qualifier
- by the same mechanism of action as in isolated stem segmentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenously applied indole-3-acetic acid (IAA) strongly promoted stem elongation over the long term in intact light-grown seedlings of both dwarf (cv Progress No. 9) and tall (cv Alaska) peas (Pisum sativum L.)”
e1“auxin promotes stem elongation in the intact plant probably by the same mechanism of action as in isolated stem segments”
The same questions in other papers
indole-3-acetic acid · growth · Lathyrus oleraceus (pea)Results differ
32 papers in the same direction as this paper · 14 in the opposite direction
- no effect
- positive
- no effect
43 papers more in this group
See all 47 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.