Abstract
Application of indoleacetic acid (IAA) and other auxins causes cultured radish (Raphanus sativus L. ;Scarlet Globe') seedling root segments to produce an increased frequency (FR, no. cm(-1)) of lateral roots (LR); in the absence of auxin, segments spontaneously form about 6 LR cm(-1). A dose-response study has revealed that the increase in FR follows a biphasic Michaelis-Menten relationship with the medium concentration of the undissociated form of IAA ([IAAH](m)). The fitted curve for phase I has a maximum response level (R(max)) of 5.2 LR per centimeter above the spontaneous FR; the [IAAH](m) giving half-maximal response (C(1/2)) is 21 nanomolar. For phase II, the values for R(max) and C(1/2) are 56 LR per centimeter and 11 micromolar, respectively. The response is variable in the transition concentration region between the two phases; in that region (but not, or much less commonly, at higher or lower [IAAH](m)), LR initiation may resume or continue after the first day. At and above 100 micromolar [IAAH](m), the roots are hyperstimulated and generally fail to respond. The developmental stage of LR formed in medium with very low [IAAH](m) (10 nanomolar) is enhanced compared to LR formed in medium lacking auxin; the stage is diminished at higher auxin levels, in inverse correlation with FR. Trends in the responses to NAA and IBA were similar, but NAA required only 0.03 times the dose of IAA, while IBA required 6 times the dose of IAA. These findings may be of use in a search for possible auxin receptors involved with LR initiation.
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Claims 12
Claim · model-written summary
Auxins increased lateral-root frequency in cultured radish root segments.
- Taxon
- radish
Raphanus sativuse0 - Material
- Scarlet Globee0
- Organ / stage
- seedling root segmentse0
- Treatment
- indoleacetic acid (IAA) and other auxinse0
- Outcome
- frequency (FR, no. cm(-1)) of lateral rootse0
- Direction
- increasede0
- Qualifier
- about 6 LR cm(-1)e0
- Comparator
- absence of auxine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of indoleacetic acid (IAA) and other auxins causes cultured radish (Raphanus sativus L. ;Scarlet Globe') seedling root segments to produce an increased frequency (FR, no. cm(-1)) of lateral roots (LR); in the absence of auxin, segments spontaneously form about 6 LR cm(-1)”
Claim · model-written summary
The IAA dose response for lateral-root frequency followed a biphasic Michaelis-Menten relationship.
- Taxon
- RadishRaphanus sativust0
- Treatment
- IAAe0
- Outcome
- increase in FRe0
- Direction
- increasee0
- Qualifier
- biphasic Michaelis-Menten relationshipe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increase in FR follows a biphasic Michaelis-Menten relationship with the medium concentration of the undissociated form of IAA ([IAAH](m))”
t0“Radish”
Claim · model-written summary
The phase I fitted maximum was 5.2 lateral roots per centimeter above spontaneous frequency.
- Taxon
- RadishRaphanus sativust0
- Outcome
- maximum response level (R(max))e0
- Direction
- maximume0
- Value
- 5.2 LR per centimetere0
- Comparator
- spontaneous FRe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The fitted curve for phase I has a maximum response level (R(max)) of 5.2 LR per centimeter above the spontaneous FR”
t0“Radish”
Claim · model-written summary
The phase I half-maximal IAA concentration was 21 nanomolar.
- Taxon
- RadishRaphanus sativust0
- Outcome
- half-maximal response (C(1/2))e0
- Value
- 21 nanomolare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the [IAAH](m) giving half-maximal response (C(1/2)) is 21 nanomolar”
t0“Radish”
Claim · model-written summary
The phase II fitted maximum was 56 lateral roots per centimeter.
- Taxon
- RadishRaphanus sativust0
- Outcome
- R(max)e0
- Value
- 56 LR per centimetere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For phase II, the values for R(max) and C(1/2) are 56 LR per centimeter and 11 micromolar, respectively”
t0“Radish”
Claim · model-written summary
The phase II half-maximal IAA concentration was 11 micromolar.
- Taxon
- RadishRaphanus sativust0
- Outcome
- C(1/2)e0
- Value
- 11 micromolare0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For phase II, the values for R(max) and C(1/2) are 56 LR per centimeter and 11 micromolar, respectively”
t0“Radish”
Claim · model-written summary
Lateral-root initiation could resume or continue after day one in the transition concentration region.
- Taxon
- RadishRaphanus sativust0
- Outcome
- LR initiation may resume or continue after the first daye0
- Qualifier
- transition concentration region between the two phasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The response is variable in the transition concentration region between the two phases; in that region (but not, or much less commonly, at higher or lower [IAAH](m)), LR initiation may resume or continue after the first day”
t0“Radish”
Claim · model-written summary
At or above 100 micromolar IAAH, roots were hyperstimulated and generally failed to respond.
- Taxon
- RadishRaphanus sativust0
- Treatment
- At and above 100 micromolar [IAAH](m)e0
- Outcome
- roots are hyperstimulated and generally fail to responde0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At and above 100 micromolar [IAAH](m), the roots are hyperstimulated and generally fail to respond”
t0“Radish”
Claim · model-written summary
Very low IAAH enhanced lateral-root developmental stage relative to no auxin.
- Taxon
- RadishRaphanus sativust0
- Treatment
- very low [IAAH](m) (10 nanomolar)e0
- Outcome
- developmental stage of LRe0
- Direction
- enhancede0
- Comparator
- medium lacking auxine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The developmental stage of LR formed in medium with very low [IAAH](m) (10 nanomolar) is enhanced compared to LR formed in medium lacking auxin”
t0“Radish”
Claim · model-written summary
Higher auxin levels diminished lateral-root developmental stage, inversely correlated with lateral-root frequency.
- Taxon
- RadishRaphanus sativust0
- Treatment
- higher auxin levelse0
- Outcome
- stagee0
- Direction
- diminishede0
- Qualifier
- inverse correlation with FRe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the stage is diminished at higher auxin levels, in inverse correlation with FR”
t0“Radish”
Claim · model-written summary
NAA showed a similar response trend but needed 0.03 times the IAA dose.
- Taxon
- RadishRaphanus sativust0
- Treatment
- NAAe0
- Outcome
- dosee0
- Direction
- onlye0
- Value
- 0.03 timese0
- Comparator
- IAAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Trends in the responses to NAA and IBA were similar, but NAA required only 0.03 times the dose of IAA”
t0“Radish”
Claim · model-written summary
IBA showed a similar response trend but needed six times the IAA dose.
- Taxon
- RadishRaphanus sativust0
- Treatment
- IBAe0
- Outcome
- dosee0
- Direction
- requirede0
- Value
- 6 timese0
- Comparator
- IAAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Trends in the responses to NAA and IBA were similar, but NAA required only 0.03 times the dose of IAA, while IBA required 6 times the dose of IAA”
t0“Radish”
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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.