Characterization of the growth and auxin physiology of roots of the tomato mutant, diageotropica

Planta. 1995;195(4):548-53. doi: 10.1007/BF00195714.


Roots of the tomato (Lycopersicon esculentum, Mill.) mutant (diageotropica (dgt) exhibit an altered phenotype. These roots are agravitropic and lack lateral roots. Relative to wild-type (VFN8) roots, dgt roots are less sensitive to growth inhibition by exogenously applied IAA and auxin transport inhibitors (phytotropins), and the roots exhibit a reduction in maximal growth inhibition in response to ethylene. However, IAA transport through roots, binding of the phytotropin, tritiated naphthylphthalamic acid ([3H]NPA), to root microsomal membranes, NPA-sensitive IAA uptake by root segments, and uptake of [3H]NPA into root segments are all similar in mutant and wild-type roots. We speculate that the reduced sensitivity of dgt root growth to auxin-transport inhibitors and ethylene is an indirect result of the reduction in sensitivity to auxin in this single gene, recessive mutant. We conclude that dgt roots, like dgt shoots, exhibit abnormalities indicating they have a defect associated with or affecting a primary site of auxin perception or action.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biological Transport / drug effects
  • Ethylenes / pharmacology
  • Gravitropism / drug effects*
  • Gravitropism / genetics
  • Herbicides / metabolism
  • Herbicides / pharmacokinetics
  • Herbicides / pharmacology
  • Indoleacetic Acids / antagonists & inhibitors*
  • Indoleacetic Acids / pharmacokinetics
  • Indoleacetic Acids / pharmacology*
  • Lycopersicon esculentum / drug effects
  • Lycopersicon esculentum / genetics*
  • Lycopersicon esculentum / growth & development
  • Lycopersicon esculentum / metabolism
  • Mutation
  • Phenotype
  • Phthalimides / metabolism
  • Phthalimides / pharmacokinetics
  • Phthalimides / pharmacology
  • Plant Growth Regulators / pharmacokinetics
  • Plant Growth Regulators / pharmacology*
  • Plant Roots / drug effects
  • Plant Roots / genetics
  • Plant Roots / growth & development*
  • Plant Roots / metabolism
  • Protein Binding


  • Ethylenes
  • Herbicides
  • Indoleacetic Acids
  • Phthalimides
  • Plant Growth Regulators
  • alpha-naphthylphthalamic acid
  • indoleacetic acid
  • ethylene