Inhibitors of Polar Auxin Transport

Niedergang-Kamien, Ethel; Leopold, A. C.

doi:10.1111/j.1399-3054.1957.tb07607.x

Cited by 85 publications

(24 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…7). It is concluded that these compounds, all of which are known to be auxin transport inhibitors (19,24), achieve their effects by a different mode of action from the phytotropins. The plant growth inhibitor lycoricidinol XIII has been shown to inhibit auxin transport by a mechanism different from that of the morphactins (15).…”

Section: Resultsmentioning

confidence: 99%

Auxin Transport Inhibitors

Katekar

Geissler²

1980

Plant Physiol.

132

View full text Add to dashboard Cite

The more active members of a proposed class of auxin transport inhibitors have been shown to have the ability to inhibit the active movement of auxin at concentrations where they have Uttle effect on auxin action and no significant auxin activity. They have also been shown to give rise to characteristic biphasic dose-response curves on cress root growth. Based on these physiological similarities and other common physiological properties, it is concluded that they may achieve their effects by a common mode of action which differs from that of other known auxin transport inhibitors. It is suggested that the name "phytotropins" be given to the class of auxin transport inhibitors now defined by a similar mode of action and common chemical properties.It has been shown that a group of chemicals which were known to affect the geotropic response can be defined by a common set of chemical requirements (16) and that these requirements are at least similar to those which can give rise to inhibition of auxin transport ( 18). The group can be divided into eight chemical types, and these are shown in Figure 1. Rules which define the chemical requirements so far known have been formulated (18). In summary, a 2-carboxyphenyl group separated by a conjugated system of atoms from a second aromatic ring may be necessary for a molecule to have high activity.At least one member of each type has been established to be an auxin transport inhibitor, as well as having the additional physiological properties of being able to abolish the root and stem geotropic responses, the phototropic response, and the apical dominance effect. From the close chemical similarity between compounds within each type, it can be inferred that members within each type may act by a similar mode of action. The broader structure-activity correlation, however, implies a relationship between the types (18). It also implies that the mode of action of the group as a whole may be different from other auxin transport inhibitors which do not conform to the chemical parameters. An investigation of this relationship, therefore, would seem warranted, especially since some compounds from within the group, e.g.NPA' III-1; CPD IV-I, and DPX 1840 VIII-I (Fig. 2), have found 'Abbreviations: CFM, methyl-2-chloro-9-hydroxyfluorene-9-carboxylate; CPD, l-(2'-carboxyphenyl)-3-phenylpropane-1,3-dione; CPP, 5-(2'-carboxyphenyl)-3-phenylpyrazole; DPX 1840, 3,3a-dihydro-2-(p-methoxyphenyl)-8H -pyrazolo(5 -1a)isoindol-8-one; NPA, N-(naphth-1-yl)-phthalamic acid; PBA, 2-(1-pyrenoyl)benzoic acid; PCIB, p-chlorophenoxyisobutyric acid; TCBA, 2,3,6-trichlorobenzoic acid; TIBA, 2,3,5-triiodobenzoic acid. use in plant physiological research, together with other auxin transport inhibitors which do not belong to the group, e.g. TIBA IX and the morphactins X (Fig. 2).To enable a class of compounds having similar physiological and chemical properties to be defined, chemicals of known high auxin transport inhibiting activity from within types II through VII were comparatively assessed for re...

show abstract

Section: Resultsmentioning

confidence: 99%

Auxin Transport Inhibitors

Katekar

Geissler²

1980

Plant Physiol.

132

View full text Add to dashboard Cite

show abstract

“…TIBA is an auxin transport inhibitor that also inhibits root growth (24) and prevents gravitropic bending in maize roots (15) and in pea roots (9). TIBA was initially dissolved in ethanol before addition to probe solution to give the measurement solution.…”

Section: Ion Substitution and Channel-blocking Experimentsmentioning

confidence: 99%

Ionic Current Changes Associated with the Gravity-Induced Bending Response in Roots of Zea mays L.

Collings¹,

White²,

Overall³

1992

Plant Physiol.

View full text Add to dashboard Cite

A vibrating probe was used to measure the changes in ionic currents around gravistimulated roots of Zea mays L. in an effort to determine whether these currents are involved in stimulus transduction from the root cap to the elongation zone. We did not observe a migration of the previously reported auxin-insensitive current efflux associated with gravity sensing (T. Bjorkman, A.C.Leopold [1987] Plant Physiol 84: 841-846) back from the root cap.Instead, beginning 10 to 15 min after gravistimulation, an asymmetry in current developed simultaneously along the root around the meristem and apical regions of the elongation zone. This asymmetry comprised a proton efflux from the upper surface, which was superimposed on the symmetrical pattern around the vertical root. The gravity-induced proton efflux was inhibited by the application of the auxin transport inhibitor, 2,3,5-triiodobenzoic acid, whereas the calcium channel blocker, lanthanum, had little effect. Because the onset of the gravity-induced current asymmetry coincided both spatially and temporally with the onset of the differential growth response, we suggest that this current efflux may result from auxin-requiring acid-growth phenomena in the upper root tissue. The implications of this simultaneous onset of both proton efflux and elongation for theories about gravity stimulus transduction are discussed.Studies of root gravitropism have focused on assessing the first stages of gravity perception by the sensing tissue (thought to be the columella cells in the root cap) and determining steps in the response that immediately precede discernible growth asymmetries in the elongation zone (8 and refs. therein). Recently, there has been considerable attention given to changes in root electrophysiology following gravity stimulation (4,5,19). The growing root tip is electrically active, and when it is placed in a conducting solution, ionic currents, measurable with the vibrating probe (14), typically enter the meristem and younger parts of the elongation zone and leave the remainder of the elongation zone and the more mature parts of the root (29).A gravitropic stimulus modifies the symmetrical current pattern found around the vertical root. Behrens et al. (4) measured changes in current parallel to the upper surface of Lepidium sativum roots. These changes were interpreted as

show abstract

“…TIBA and morphactins are also well known for many years to inhibit polar auxin transport in plants and to induce abnormalities in leaf and/or shoot growth. There are numerous reports of these compounds relevant to these aspects [9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Differential effects of N-1-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) on auxin control of swelling of the shoots of Bryophyllum calycinum Salisb.

et al. 2017

View full text Add to dashboard Cite

The effects of N-1-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) on the swelling of the stem in intact and decapitated plants of Bryophyllum calycinum in relation to the interaction with auxin, indole-3-acetic acid (IAA), are described. NPA induced conspicuous local internode swelling only in the area of its application in intact plants and in the decapitated internode in the case of simultaneous application of IAA on the top of the internode. By contrast, TIBA applied to an internode of intact plants induced swelling along the entire internode above the treatment area, and similar results were obtained in the decapitated internode when TIBA was applied in the middle of the internode and IAA was applied onto the top of the internode. The differential effect of NPA and TIBA on stem swelling in B. calycinum is discussed in relation to their differential mode of action on auxin transport.

show abstract

Inhibitors of Polar Auxin Transport

Cited by 85 publications

References 13 publications

Auxin Transport Inhibitors

Auxin Transport Inhibitors

Ionic Current Changes Associated with the Gravity-Induced Bending Response in Roots of Zea mays L.

Differential effects of N-1-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) on auxin control of swelling of the shoots of Bryophyllum calycinum Salisb.

Contact Info

Product

Resources

About