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Cited by 284Plant Molecular Biology ResearchPlant Parasitism and ResistanceFlowering Plant Growth and Cultivation

The hormonal regulation of axillary bud growth in Arabidopsis

Open access
Chatfield, Steven P., Stirnberg, Petra, Forde, Brian G., Leyser, Ottoline·2000·The Plant Journal
DOI 10.1046/j.1365-313x.2000.00862.x
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Abstract

Apically derived auxin has long been known to inhibit lateral bud growth, but since it appears not to enter the bud, it has been proposed that its inhibitory effect is mediated by a second messenger. Candidates include the plant hormones ethylene, cytokinin and abscisic acid. We have developed a new assay to study this phenomenon using the model plant Arabidopsis. The assay allows study of the effects of both apical and basal hormone applications on the growth of buds on excised nodal sections. We have shown that apical auxin can inhibit the growth of small buds, but larger buds were found to have lost competence to respond. We have used the assay with nodes from wild-type and hormone-signalling mutants to test the role of ethylene, cytokinin and abscisic acid in bud inhibition by apical auxin. Our data eliminate ethylene as a second messenger for auxin-mediated bud inhibition. Similarly, abscisic acid signalling is not to be required for auxin action, although basally applied abscisic can enhance inhibition by apical auxin and apically applied abscisic acid can reduce it. By contrast, basally applied cytokinin was found to release lateral buds from inhibition by apical auxin, while apically applied cytokinin dramatically increased the duration of inhibition. These results are consistent with cytokinin acting independently to regulate bud growth, rather than as a second messenger for auxin. However, in the absence of cytokinin-signalling mutants, a role for cytokinin as a second messenger for auxin cannot be ruled out.

Integrity signals

Registry

Crossref · 10.1046/j.1365-313x.2000.00862.x

Cites

59 of 59 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

2 of 34 cited sources checked · 2 supported · 0 flagged

  • Premisecitation

    Auxin levels in the bud increase as lateral buds begin to enlarge and grow.

    “auxin levels in the bud actually increase as lateral buds begin to enlarge and grow (Gocal et al., 1991;Hillman, 1984;Pearce et al., 1995).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Gocal et al., 1991 source
    • cites Hillman, 1984

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Pearce et al., 1995 source
  • Findingown data

    Despite lower growth rates, inhibition by apical 1 mM NAA was clearly demonstrated with both etr1 and AVG treatments.

    “However, despite the lower growth rates, inhibition by apical 1 mM NAA was clearly demonstrated with both etr1 and AVG treatments.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The etr1 mutant is ethylene-insensitive.
    • Rests on an assumption: AVG inhibits ethylene biosynthesis.
  • Findingown data

    Apical NAA at 10 mM can inhibit outgrowth from longer buds up to 3.5 mm long at excision.

    “NAA at this concentration (10 mM) could also inhibit outgrowth from longer buds, up to 3.5 mm long at excision (data not shown).”
    Quote in the paperNot a substantial claim
  • Findingown data

    When both hormones were applied basally, bud growth was similar to untreated controls.

    “When both hormones were applied basally, bud growth was similar to that of untreated controls.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Basally applied ABA can enhance inhibition by apical auxin.

    “although basally applied abscisic can enhance inhibition by apical auxin”
    • Also stated in: § The effect of ethylene and ABA on auxin-mediated inhibition · plain
      “Combining basal 3 mM ABA with apical 1 mM NAA increased the duration of inhibition signi®cantly compared with apical NAA alone.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 33
  • Classified as probably not a substantial claim. 12

  • May combine two claims.

    Premisecitation

    Auxin levels increase as buds begin to grow, and bud activity correlates with the presence of active polar auxin transport.

    “Certainly, auxin levels increase as buds begin to grow (Gocal et al., 1991;Hillman, 1984;Pearce et al., 1995), and bud activity correlates with the presence of active polar auxin transport (Morris and Johnson, 1990;Morris, 1977).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Gocal et al., 1991 source
    • cites Morris and Johnson, 1990 source
    • cites Morris, 1977 source

  • May combine two claims.

    Findingown data

    Some larger buds (2-5 mm) unresponsive to 1 mM NAA can be inhibited by higher concentrations of apical NAA, but even 10 mM NAA may not inhibit buds longer than 5 mm.

    “We have found that some of the larger buds (2± 5 mm), which appear unresponsive to 1 mM NAA, can be inhibited by higher concentrations of apical NAA, but that even 10 mM NAA may not inhibit buds longer than 5 mm (data not shown).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    When NAA was supplied basally and BA apically, mean rate of lateral outgrowth was the same as controls for the first 120 h, after which buds tended to die.

    “When the orientation of the hormones was reversed, i.e.NAA basally and BA apically, the mean rate of lateral outgrowth was the same as the controls for the ®rst 120 h, after which the buds from this treatment tended to die.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Basal 1 mM BA caused a slight increase in the rate of lateral growth; buds were on average one-third longer than controls after 72 h.

    “Basal 1 mM BA caused a slight increase in the rate of lateral growth, such that buds were on average one-third longer than controls after 72 h.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    abi1-1 buds were completely insensitive to ABA in any orientation and auxin inhibition was unaffected.

    “When abi1-1 was tested, it was found that the buds were completely insensitive to ABA in any orientation and auxin inhibition was unaffected (Figure 5d).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The abi1-1 and abi2-1 mutants are ABA-insensitive.

  • May combine two claims.

    Findingown data

    Inhibition by apical 1 mM NAA was more prolonged when combined with AVG (24 h longer on average) or etr1 (5-6 days longer).

    “In fact, inhibition by apical 1 mM NAA was more prolonged when combined with either AVG or etr1 in the assay (24 h longer, on average, with AVG and 5±6 days longer with etr1).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The etr1 mutant is ethylene-insensitive.
    • Rests on an assumption: AVG inhibits ethylene biosynthesis.

  • May combine two claims.

    Findingown data

    Apical NAA at 10 mM inhibits most buds for at least 7 days and many for 10-14 days.

    “Concentrations of apical NAA higher than 1 mM prolonged the period of inhibition, with 10 mM inhibiting most buds for at least 7 days and many for the duration of the experiment: 10±14 days (Figure 3b).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Buds larger than 1.5 mm at excision are increasingly less likely to be inhibited by 1 mM apical NAA; most buds greater than 3 mm grow out at rates not significantly different from controls.

    “Buds larger than 1.5 mm at excision of the nodal section were increasingly less likely to be inhibited by 1 mM NAA for any period, and most lateral buds greater than 3 mm in length grew out at rates not signi®cantly different from control buds.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Apical 2,4-D completely inhibited buds for 2-10 days and when growth began it proceeded at a greatly reduced rate.

    “By contrast, when apical 2,4-D was used, the buds were completely inhibited for 2± 10 days and when growth began it proceeded at a greatly reduced rate.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Landsberg erecta appeared generally more sensitive to ABA than Columbia; 3 mM ABA in any orientation dramatically reduced bud outgrowth.

    “It was found that Landsberg erecta appeared generally more sensitive to ABA than Columbia.In Landsberg, the rate of bud outgrowth was dramatically reduced (and to approximately the same degree) by 3 mM ABA in any orientation”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Apical NPA prevents or partially relieves inhibition of bud outgrowth by apical NAA.

    “When the polar transport inhibitor 1-N-naphthylphthalamic acid (NPA) was supplied apically (1 mM), inhibition by 1 mM apical NAA was partially relieved (Figure 4b).”
    • Also stated in: § Auxin and bud outgrowth Our data show a direct relationship between the concentration of apical auxin and the duration of the inhibition of bud outgrowth (Figure 3).Other workers have found that increasing the concentration of auxin applied to the cut stump of decapitated plants (Thimann, 1937;Went, 1939), or to the apical end of explants (Tamas et al., 1989), decreases the ®nal length of lateral buds.Wickson and Thimann (1958) observed that buds on nodal sections of Pisum sativum immersed in nutrient solutions were inhibited for approximately the same period over a range of IAA concentrations.The buds would `breakaway' after 5 days, but their subsequent growth was slower at higher IAA concentrations.In contrast, we have found that, when apical NAA is applied, the time to breakaway increases as the concentration is raised from 0.1 to 10 mM, often with little difference in the subsequent rate of outgrowth (Figure 3b).The mechanism behind this concentrationdependent timing of breakaway is unclear.A decline in the sensitivity of some auxin-responsive tissues may occur, or the ability of the nodal sections to take up and/or transport auxin may diminish with time and the build-up of callus at the cut stump.Perhaps a substance accumulates that counteracts inhibition by auxin.For instance, cells at the base of the nodal sections that have begun to differentiate into root tissue may begin to synthesize and release cytokinins.We have established that there is no signi®cant decrease in the potency of the NAA in the split plates during the course of the experiment.Plates used in the assay for 8 days were replenished with fresh nodal sections and were found to inhibit bud outgrowth for as long as fresh plates (data not shown). The assay has also revealed a trend for decreasing sensitivity to inhibition by apical auxin as lateral bud size increases.We have found that some of the larger buds (2± 5 mm), which appear unresponsive to 1 mM NAA, can be inhibited by higher concentrations of apical NAA, but that even 10 mM NAA may not inhibit buds longer than 5 mm (data not shown).Therefore, it appears that, with increasing size, buds loose competence to respond to auxin.The molecular basis for this change is unknown.One possibility is that the transition to auxin resistance corresponds to the establishment of auxin synthesis and transport in the developing bud as suggested by Snow (1937).Certainly, auxin levels increase as buds begin to grow (Gocal et al., 1991;Hillman, 1984;Pearce et al., 1995), and bud activity correlates with the presence of active polar auxin transport (Morris and Johnson, 1990;Morris, 1977). Supplying apical NPA prevented inhibition by apical NAA.This supports the conclusion reached by Tamas et al. (1989) that basipetal auxin transport from the apex is required for bud growth inhibition.In addition, our observation that basally supplied auxins failed to inhibit lateral bud outgrowth is in agreement with their ®ndings.However, they also found that supplying basal IAA to bean nodal explants could relieve inhibition by apical IAA, which is contrary to our results using NAA.This may re¯ect a difference in the action of these speci®c auxins (e.g.uptake into cells), or in the responses of the two species to basal auxin.The difference in the effects of basally and apically supplied auxin is not explained by a difference in the quantity of hormone reaching the bud.By the addition of dyes, we have established that there is signi®cant bulk ¯ow of solutes from the basal media block to the cauline leaf and later to the growing bud in the transpiration stream (data not shown).However, dye supplied in the apical media block did not appear in the leaf or bud.In addition, Lim and Tamas (1989) used 14 C-IAA to show that the quantity of IAA transported to the bud from the cut apical surface of explants did not exceed that reaching the bud from the basal end.We were able to con®rm this result for Arabidopsis explants using 14 C-IAA in our own assay (data not shown). · plain
      “Supplying apical NPA prevented inhibition by apical NAA.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Basal and apical 3 mM ABA did not affect the rate of bud outgrowth significantly in Columbia, but when supplied in both media blocks a slight reduction was observed.

    “Basal and apical 3 mM ABA did not affect the rate of bud outgrowth signi®cantly, but, when supplied in both media blocks, a slight reduction in growth rate was observed.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The rate of lateral outgrowth in the etr1 mutant was slower than in wild-type, and 5 mM AVG reduced the rate of bud growth substantially.

    “The rate of lateral outgrowth in the etr1 mutant was slower than in wild-type, and 5 mM AVG, supplied in both media blocks, also reduced the rate of bud growth substantially.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The etr1 mutant is ethylene-insensitive.
    • Rests on an assumption: AVG inhibits ethylene biosynthesis.

  • May combine two claims.

    Findingown data

    Apical NAA at 0.5 mM inhibits outgrowth of many buds but usually for a shorter period than 1 mM; 0.1 mM does not affect the rate of bud growth.

    “Apical 0.5 mM NAA inhibited the outgrowth of many buds, but usually for a shorter period than 1 mM NAA, and apical 0.1 mM NAA did not affect the rate of bud growth (Figure 3b).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In inverted nodes, NAA at the inverted apical end inhibited outgrowth, but basal NAA had no effect.

    “Even with the orientation of the nodes reversed, NAA supplied at the inverted apical end was found to inhibit outgrowth, but still had no effect when provided at the basal end (data not shown).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Apical cytokinin and cytokinin applied to both sides had little effect on bud growth.

    “Apical cytokinin and cytokinin applied to both sides had little effect.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Apical IAA at 1 mM prevented outgrowth for 2-4 days and was similar in effect to 0.5 mM NAA.

    “IAA at a concentration of 1 mM prevented outgrowth for 2±4 days and was similar in effect to 0.5 mM NAA.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Apical IAA and 2,4-D also inhibit bud outgrowth; IAA is less potent than NAA.

    “The most prevalent natural auxin, IAA, and the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) supplied apically were also able to inhibit bud outgrowth (Figure 3c).Apical IAA was found to be a less potent inhibitor than NAA.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    When apical NAA is applied, time to breakaway increases as the concentration is raised from 0.1 to 10 mM, often with little difference in subsequent rate of outgrowth.

    “In contrast, we have found that, when apical NAA is applied, the time to breakaway increases as the concentration is raised from 0.1 to 10 mM, often with little difference in the subsequent rate of outgrowth (Figure 3b).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Growth of lateral shoots from excised node 1 was slow for the first 24 h (0-1 mm), then increased to an average of 7 mm per day between 72 and 144 h.

    “Growth of lateral shoots from excised node 1 was slow for the ®rst 24 h (0±1 mm).The growth rate then increased steadily to settle at an average of 7 mm per day between 72 and 144 h (Figure 2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Apical NPA can release auxin inhibition of bud outgrowth, but basal NPA cannot.

    “Apical NPA can release auxin inhibition of bud outgrowth, but basal NPA cannot (b).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The excised nodal section assay reproduces the hormonal regulation of axillary bud growth in intact Arabidopsis plants.

  • May combine two claims.

    Findingown data

    In the assay, the cytokinin BA applied basally, apically, or both had relatively little effect on lateral bud outgrowth, although 1 mM BA applied basally slightly stimulated growth rate.

    “The cytokinin BA, when applied basally, apically or both, had relatively little effect on the outgrowth of the lateral buds in the assay, although a small stimulation of the rate of growth was seen when 1 mM BA was added basally.”
    • Also stated in: § Set-up and measurements · hedged
      “When supplied alone, BA generally has little effect on the rate of bud outgrowth (a), but when supplied basally or apically with apical NAA, BA can, respectively, release or enhance inhibition of lateral bud outgrowth (b).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Small buds are more sensitive to apical auxin than large buds, which become essentially unresponsive to the hormone.

    “Small buds are more sensitive to apical auxin than large buds, which become essentially unresponsive to the hormone.”
    • Also stated in: § Set-up and measurements · plain
      “Buds longer than 1.5 mm at excision become unresponsive to inhibition by 1 mM NAA (a).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The excised nodal section assay reproduces the hormonal regulation of axillary bud growth in intact Arabidopsis plants.

  • May combine two claims.

    Findingown data

    Apical ABA reduces auxin-mediated inhibition, whereas basal ABA enhances it.

    “Apical ABA can reduce auxinmediated inhibition, whilst basal ABA enhances it.”
    • Also stated in: § Set-up and measurements · plain
      “When combined with apical 1 mM NAA, the ABA enhances inhibition when supplied basally, reduces it when supplied apically, and has little effect when supplied to both sides (c).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The hormone concentrations used in the assay (e.g., 1 mM NAA, 3 mM ABA) are within a physiological range and their effects reflect natural hormonal roles.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Buds on nodal sections from the Landsberg erecta ecotype grew out more slowly than those of Columbia, reducing the difference between auxin-treated and control buds.

    “It was also noted that buds on nodal sections from the Landsberg erecta ecotype grew out more slowly than those of Columbia, and hence the difference between auxin-treated and control buds is reduced.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The growth curve for lateral buds from node 1 on intact Columbia plants was more linear; growth was significantly slower, attaining only 3.5 mm per day after 120 h.

    “The growth curve for lateral buds from node 1 on intact Columbia plants grown in sterile culture, under the same light and temperature regimes, was more linear than for the excised nodes (Figure 2).Initially growth rates were similar, but although the growth rate of lateral shoots on excised nodes accelerated after 72 h, the comparative growth of lateral shoots on intact plants was signi®cantly Sl”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The assay allows study of the effects of both apical and basal hormone applications on the growth of buds on excised nodal sections.

    “The assay allows study of the effects of both apical and basal hormone applications on the growth of buds on excised nodal sections.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Ethylene biosynthesis and ethylene action do not mediate auxin inhibition of lateral bud growth.

    “Our data eliminate ethylene as a second messenger for auxin-mediated bud inhibition.”
    • Also stated in: § The effect of ethylene and ABA on auxin-mediated inhibition · plain
      “Hence ethylene biosynthesis and ethylene action do not mediate auxin inhibition of lateral bud growth.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The etr1 mutant is ethylene-insensitive.
    • Rests on an assumption: AVG inhibits ethylene biosynthesis.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Apical auxin influences the export of cytokinins from roots.

    “The export of cytokinins from roots has been shown to be in¯uenced by apical auxin, and this has led to the hypothesis that inhibition by apical auxin is mediated wholly or partly by its in¯uence on cytokinin export from the roots (Bangerth, 1994).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bangerth, 1994 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Buds on nodal sections of Pisum sativum immersed in nutrient solutions were inhibited for approximately the same period over a range of IAA concentrations; they broke away after 5 days, but subsequent growth was slower at higher IAA concentrations.

    “Wickson and Thimann (1958) observed that buds on nodal sections of Pisum sativum immersed in nutrient solutions were inhibited for approximately the same period over a range of IAA concentrations.The buds would `breakaway' after 5 days, but their subsequent growth was slower at higher IAA concentrations.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Wickson and Thimann (1958) source

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The assay allows various combinations of plant hormones and/or phytotropins and/or metabolic inhibitors to be supplied to each side of the node separately.

    “The assay we have developed allows various combinations of plant hormones and/or phytotropins and/or metabolic inhibitors to be supplied to each side of the node separately.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Increasing the concentration of auxin applied to the cut stump of decapitated plants or to the apical end of explants decreases the final length of lateral buds.

    “Other workers have found that increasing the concentration of auxin applied to the cut stump of decapitated plants (Thimann, 1937;Went, 1939), or to the apical end of explants (Tamas et al., 1989), decreases the ®nal length of lateral buds.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Thimann, 1937 source
    • cites Went, 1939 source
    • cites Tamas et al., 1989 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Kinetin enhances the movement of 32P and 14C-sucrose towards the cut stump to which IAA has been applied.

    “Kinetin has also been found to enhance the movement of 32 P and 14 C-sucrose towards the cut stump to which IAA has been applied (Seth and Wareing, 1964).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Seth and Wareing, 1964 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    In plants, roots are believed to be the major site of cytokinin synthesis and export cytokinins to the shoot via the xylem.

    “In plants, the roots are believed to be the major site of cytokinin synthesis (Chen et al., 1985), and to export these substances to the shoot via the xylem.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Chen et al., 1985 source

  • May combine two claims.

    Premisecitation

    The Arabidopsis era1 mutant has enhanced ABA response and reduced branching, providing evidence for a role for ABA in regulating bud growth.

    “Further evidence for a role for ABA in regulating bud growth comes from analysis of the era1 mutant of Arabidopsis which has an enhanced response to ABA and reduced branching (Pei et al., 1998).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Pei et al., 1998 source

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    Individuals were excluded from the data set if the growing bud had touched the medium, if the cut end of the internode had been pushed out of the medium by elongation of the stem, if condensation may have bridged the gap between the two media blocks, or where microbial contamination was visible on the plate.

    “Individuals were excluded from the data set if the growing bud had touched the medium, if the cut end of the internode had been pushed out of the medium by elongation of the stem, if condensation may have bridged the gap between the two media blocks, or where microbial contamination was visible on the plate.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    All data displayed in the paper represent the growth responses of lateral buds from node 1.

    “All of the data displayed in this paper represent the growth responses of lateral buds from node 1.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The trough between the two media blocks was checked carefully for any bridges and dried to prevent cross-contamination.

    “This trough was checked carefully for any bridges between the two media blocks and dried in the laminar ¯ow hood, parallel to the air¯ow, for a further 30 min.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Cytokinins stimulate bud outgrowth when applied to lateral buds of plants with an intact apex, or to decapitated plants treated with inhibitory concentrations of apical auxin.

    “Cytokinins have been shown to stimulate bud outgrowth when applied to the lateral buds of plants with an intact apex, or to decapitated plants to which inhibitory concentrations of apical auxin were applied (Mok, 1994).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Mok, 1994

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The plates were left at 4°C for at least 72 h to allow the hormone to diffuse evenly throughout the media.

    “The plates were then left at 4°C for at least 72 h to allow the hormone to diffuse evenly throughout the media.”
    Quote in the paperNot a substantial claim
40 of 40

  • The paper relies on this without support.

    The etr1 mutant is ethylene-insensitive.

    “the ethylene-insensitive mutant etr1”

  • The paper relies on this without support.

    The abi1-1 and abi2-1 mutants are ABA-insensitive.

    “the ABA-insensitive mutants abi1-1 and abi2-1”

  • The paper relies on this without support.

    AVG inhibits ethylene biosynthesis.

    “the ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG)”

  • The paper relies on this without support.

    The etr1, abi1, and abi2 mutants used are specific and effective in blocking ethylene action and ABA signalling, respectively, in the assayed buds.

    “Our own data, from experiments with AVG and the etr1 mutant, demonstrate that ethylene biosynthesis and ethylene action, respectively, are not required for inhibition of bud outgrowth by apical auxin.”
    “Buds from the ABA-insensitive mutants abi1 and abi2 have a wild-type response to apical NAA in the assay.”

  • The paper relies on this without support.

    The excised nodal section assay reproduces the hormonal regulation of axillary bud growth in intact Arabidopsis plants.

    “The assay that we have developed, combined with the wide range of Arabidopsis mutants available, is proving a valuable method for investigating the roles of different hormones in the inhibition and outgrowth of lateral buds in Arabidopsis.”
    “A comparison of the rates of lateral bud outgrowth from the lowest node of intact Arabidopsis plants (Columbia ecotype) and from the same node on excised untreated sections.”

  • The paper relies on this without support.

    The hormone concentrations used in the assay (e.g., 1 mM NAA, 3 mM ABA) are within a physiological range and their effects reflect natural hormonal roles.

    “However, it is also possible that one or more of the observed responses to ABA may be non-physiological, due perhaps to the concentration of the mixed isomers used and/or contact with ectopic tissues.”
6 of 6

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • NPA is described as both partly and fully reversing inhibition

    Minor

    The results say apical NPA only partially relieved inhibition by apical NAA, whereas the discussion says it prevented that inhibition.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 3

  1. Hillman J., 1984, Hormonal Plant Physiology, 127
  2. Russell W., 1988, Plant Growth Substances, 419
  3. Tucker D.J., 1980, Apical dominance. A personal view., Br. Plant Growth Regul. Group News Bull., 4, 1

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Authors
Chatfield, S. P., Stirnberg, P., Forde, B. G., & Leyser, O.
Affiliations
  • University of York (GB)
  • Lancaster University (GB)
Corresponding author
Leyser, Ottoline
ORCID
Venue
The Plant Journal
Publisher
Wiley
Published
2000-10
Volume
24
Issue
2
Pages
159-169
ISSN
  • 0960-7412 (ISSN-L)
  • 1365-313X
DOI
10.1046/j.1365-313x.2000.00862.x
OpenAlex
W2070702008
Semantic Scholar
e5cf2b14ba6d4791675335aae6be357567843f9b
Cited by
284
References
54
Citations by year
2026: 6 · 2025: 12 · 2024: 14 · 2023: 9 · 2022: 19 · 2021: 14 · 2020: 12 · 2019: 12 · 2018: 14 · 2017: 8 · 2016: 14 · 2015: 14 · 2014: 8 · 2013: 8 · 2012: 10
FWCI
14.52
Type
journal article
Language
en
Open access
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor, 450 d)
Locations
  • The Plant Journal (publishedVersion)
  • PubMed (publishedVersion)
  • Lancaster EPrints (Lancaster University) (submittedVersion)
  • White Rose Research Online (University of Leeds, The University of Sheffield, University of York) (submittedVersion)
Funders
Directorate for Biological Sciences
Topics
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Plant Molecular Biology Research
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Plant Parasitism and Resistance
  • Life Sciences › Agricultural and Biological Sciences › Plant Science › Flowering Plant Growth and Cultivation
Keywords
axillary bud outgrowth, cytokinins, ethylene, abscisic acid, second messengers, Arabidopsis thaliana
MeSH terms
Abscisic Acid, Cytokinins, Dose-Response Relationship, Drug, Drug Interactions, Ethylenes, Indoleacetic Acids, Plant Growth Regulators, Arabidopsis, Plant Shoots

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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