Abstract
The localization of the auxin receptor relevant to the control of elongation growth is still a matter of controversy. Auxin‐induced elongation of maize coleoptile segments was measured by means of a high resolution auxanometer. When indole‐3‐acetic acid (IAA) was removed from the bathing solution, a rapid cessation of auxin‐induced elongation was detected. This decline was delayed when the auxin efflux carrier was blocked by the phytotropins naphthylphthalamic acid (NPA) and pyrenoylbenzoic acid (PBA) or by triiodobenzoic acid (TIBA). The IAA concentration in NPA‐pretreated segments was 2–3 times higher than in NPA‐free controls 35 min after the removal of IAA in the bathing medium. A similar rapid drop of growth after removal of auxin was observed for the rapidly‐transported synthetic auxin, naphthaleneacetic acid (NAA). When the auxin efflux was blocked, growth induced by NAA was sustained much longer than IAA‐stimulated elongation. In comparison with NAA, the synthetic auxin 2,4‐dichlorophenoxyacetic acid (2,4‐D) is known to be excreted very slowly by the efflux carrier. 2,4‐D‐induced growth remained at a stimulated level when the auxin was washed off, even in the absence of any auxin efflux inhibitor. We conclude from these results that the presence of intracellular auxin is a necessary and sufficient condition for sustained auxin‐induced elongation growth, at least for the phases during the 2 h after its application. Consequently, we postulate the existence of an intracellular auxin receptor relevant to the control of growth.
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 8
Claim · model-written summary
Removing IAA rapidly stopped auxin-induced maize coleoptile elongation.
- Organ / stage
- coleoptile segmentse1
- Treatment
- indole‐3‐acetic acid (IAA) was removede0
- Outcome
- auxin‐induced elongatione0
- Direction
- cessatione0
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When indole‐3‐acetic acid (IAA) was removed from the bathing solution, a rapid cessation of auxin‐induced elongation was detected.”
e1“maize coleoptile segments”
Claim · model-written summary
Efflux carrier blockers delayed the decline in elongation after IAA removal.
- Treatment
- naphthylphthalamic acid (NPA) and pyrenoylbenzoic acid (PBA) or by triiodobenzoic acid (TIBA)e0
- Outcome
- declinee0
- Direction
- delayede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This decline was delayed when the auxin efflux carrier was blocked by the phytotropins naphthylphthalamic acid (NPA) and pyrenoylbenzoic acid (PBA) or by triiodobenzoic acid (TIBA).”
e1“maize coleoptile segments”
Claim · model-written summary
IAA concentration was 2–3 times higher in NPA-pretreated segments than NPA-free controls 35 minutes after removal.
- Treatment
- NPA‐pretreatede0
- Outcome
- IAA concentratione0
- Direction
- highere0
- Value
- 2–3 timese0
- Qualifier
- 35 min after the removal of IAAe0
- Comparator
- NPA‐free controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The IAA concentration in NPA‐pretreated segments was 2–3 times higher than in NPA‐free controls 35 min after the removal of IAA in the bathing medium.”
e1“maize coleoptile segments”
Claim · model-written summary
Removing NAA also caused a rapid decline in maize coleoptile growth.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A similar rapid drop of growth after removal of auxin was observed for the rapidly‐transported synthetic auxin, naphthaleneacetic acid (NAA).”
e1“maize coleoptile segments”
Claim · model-written summary
Blocking auxin efflux sustained NAA-induced growth longer than IAA-stimulated elongation.
- Treatment
- auxin efflux was blockede0
- Outcome
- growth induced by NAAe0
- Direction
- sustained much longere0
- Comparator
- IAA‐stimulated elongatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When the auxin efflux was blocked, growth induced by NAA was sustained much longer than IAA‐stimulated elongation.”
e1“maize coleoptile segments”
Claim · model-written summary
Growth stimulated by 2,4-D persisted after auxin washout without an efflux inhibitor.
- Treatment
- auxin was washed offe0
- Outcome
- 2,4‐D‐induced growthe0
- Direction
- remained at a stimulated levele0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“2,4‐D‐induced growth remained at a stimulated level when the auxin was washed off, even in the absence of any auxin efflux inhibitor.”
e1“maize coleoptile segments”
Claim · model-written summary
The authors concluded that intracellular auxin is necessary and sufficient for sustained elongation during the first two hours.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the presence of intracellular auxin is a necessary and sufficient condition for sustained auxin‐induced elongation growth, at least for the phases during the 2 h after its application”
e1“maize coleoptile segments”
Claim · model-written summary
The authors postulated an intracellular receptor controlling growth.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we postulate the existence of an intracellular auxin receptor relevant to the control of growth”
e1“maize coleoptile segments”
The same questions in other papers
indole-3-acetic acid · physiology: hormones · Zea mays (maize)Positive and negative results
3 in the opposite direction
- positive
- positive
- positive
class · growth · Zea mays (maize)Positive and negative results
52 papers in the same direction as this paper · 15 in the opposite direction
- no effect
- negative
- negative
64 papers more in this group
See all 68 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.