Graviresponsiveness of surgically altered primary roots of Zea mays

Emily Maimon, Randy Moore

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

We examined the gravitropic responses of surgically altered primary roots of Zea mays to determine the route by which gravitropic inhibitors move from the root tip to the elongating zone. Horizontally oriented roots, from which a 1-mm-wide girdle of epidermis plus 2-10 layers of cortex were removed from the apex of the elongating zone, curve downward. However, curvature occurred only apical to the girdle. Filling the girdle with mucilage-like material transmits curvature beyond the girdle. Vertically oriented roots with a 'half-girdle' (i.e. the epidermis and 2-10 layers of the cortex removed from half of the circumference of the apex of the elongating zone) curve away from the girdle. Inserting the half-girdle at the base of the elongating zone induces curvature towards the girdle. Filling the half-circumference girdles with mucilage-like material reduced curvature significantly. Stripping the epidermis and outer 2-5 layers of cortex from the terminal 1.5 cm of one side of a primary root induces curvature towards the cut, irrespective of the root's orientation to gravity. This effect is not due to desiccation since treated roots submerged in water also curved towards their cut surface. Coating a root's cut surface with a mucilage-like substance minimizes curvature. These results suggest that the outer cell-layers of the root, especially the epidermis, play an important role in root gravicurvature, and the gravitropic signals emanating from the root tip can move apoplastically through mucilage.

Original languageEnglish (US)
Pages (from-to)145-151
Number of pages7
JournalAnnals of Botany
Volume67
Issue number2
StatePublished - Feb 1 1991

Keywords

  • Corn
  • Cortex
  • Epidermis
  • Gravitropism (root)
  • Mucilage
  • Zea mays. Yellow Dent

Fingerprint Dive into the research topics of 'Graviresponsiveness of surgically altered primary roots of Zea mays'. Together they form a unique fingerprint.

Cite this