Abstract
The partially agravitropic growth habit of roots of an auxin-resistant mutant of Arabidopsis thaliana, axr4, was restored by the addition of 30-300 nM 1-naphthaleneacetic acid (NAA) to the growth medium. Neither indole 3-acetic acid (IAA) nor 2,4-dichlorophenoxyacetic acid (2,4-D) showed such an effect. Growth of axr4 roots was resistant to IAA and 2,4-D, but not at all to NAA. The differential effects of the three auxins suggest that the defects of axr4 result from a lower auxin influx into its cells. The partially agravitropic growth habit of axr1 roots, which was less severe than that of axr4 roots, was only slightly affected by the three auxins in the growth medium at concentrations up to 300 nM; growth of axr1 roots was resistant to all three of the auxins. These results suggest that the lesion of axrl mutants is different from that of axr4.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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2,4-Dichlorophenoxyacetic Acid / pharmacology
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Arabidopsis / drug effects*
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Arabidopsis / genetics*
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Arabidopsis / growth & development
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Arabidopsis Proteins*
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Darkness
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Dose-Response Relationship, Drug
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Genes, Plant
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Gravitropism / drug effects*
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Gravitropism / genetics
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Growth Substances*
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Herbicides / pharmacology
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Indoleacetic Acids / pharmacology*
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Mutation*
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Naphthaleneacetic Acids / pharmacology
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Plant Growth Regulators / pharmacology*
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Plant Proteins / genetics
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Plant Roots / drug effects
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Plant Roots / genetics
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Plant Roots / growth & development
Substances
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AUX1 protein, Arabidopsis
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AXR1 protein, Arabidopsis
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Arabidopsis Proteins
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Growth Substances
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Herbicides
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Indoleacetic Acids
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Naphthaleneacetic Acids
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Plant Growth Regulators
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Plant Proteins
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2,4-Dichlorophenoxyacetic Acid
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1-naphthaleneacetic acid
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indoleacetic acid