The light-induced reduction of the gravitropic growth-orientation of seedlings of Arabidopsis thaliana (L.) Heynh. is a photomorphogenic response mediated synergistically by the far-red-absorbing forms of phytochromes A and B

Planta. 1996;199(4):511-4. doi: 10.1007/BF00195180.


Hypocotyls of dark-grown seedlings of Arabidosis thaliana exhibit a strong negative gravitropism, which is reduced by red and also by long-wavelength, far-red light treatments. Light treatments using phytochrome A (phyA)- and phytochrome B (phyB)-deficient mutants showed that this response is controlled by phyB in a red/far-red reversible way, and by phyA in a non-reversible, very-low-fluence response. Crosses of the previously analyzed phyB-1 allele (in the ecotype Landsberg erecta background) to the ecotype Nossen wild-type (WT) background resulted in a WT-like negative gravitropism in darkness, indicating that the previously described gravitropic randomization observed with phyB-1 in the dark is likely due to a second mutation independent of that in the PHYB gene.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis
  • Arabidopsis Proteins
  • Gravitropism*
  • Hypocotyl
  • Light
  • Photoreceptor Cells*
  • Phytochrome / genetics
  • Phytochrome / metabolism*
  • Phytochrome A
  • Phytochrome B
  • Plants
  • Transcription Factors*


  • Arabidopsis Proteins
  • PHYA protein, Arabidopsis
  • PHYB protein, Arabidopsis
  • Phytochrome A
  • Transcription Factors
  • Phytochrome
  • Phytochrome B