Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1972 Jul;50(1):35–42. doi: 10.1104/pp.50.1.35

Control and Kinetics of Branch Root Formation in Cultured Root Segments of Haplopappus ravenii

L M Blakely a, Shirley J Rodaway a, Lauren B Hollen a, Susan G Croker a
PMCID: PMC367312  PMID: 16658129

Abstract

Branch root formation required only the presence of minerals, sucrose as a carbon source, and an auxin. The number of primordia formed was a function of auxin concentration. With naphthaleneacetic acid at 0.1 mg/l, up to 60 or more branches were formed per centimeter of Haplopappus ravenii root segment. Under our conditions, pea root segments formed only five or six branches per centimeter, but tomato and radish, like H. ravenii, formed large numbers of branches. Cytokinin inhibited branch formation, while gibberellic acid was without effect. Vitamins were not required for branch formation, although they enhanced elongation. Up to 5 days were required for the maximum number of stable branch primordia to form under the influence of naphthaleneacetic acid. If naphthaleneacetic acid was withdrawn earlier, fewer branch primordia developed. The requirement for a lengthy exposure to naphthaleneacetic acid, the kinetics of the response, and the ease with which naphthaleneacetic acid could be rinsed out of the tissue with consequent cessation of branch root formation, were similar to other hormone-regulated developmental systems. Anatomical and cytological studies were made of segments exposed for various times to auxin. The segments were mostly diarch, and branches formed obliquely to protoxylem poles. While primarily only pericycle-endodermis cells divided, both these and cortex cells responded in the first 24 hours exposure to naphthaleneacetic acid with enlarged nuclei and nucleoli, and a few cortical cells divided. Maximum nucleus and nucleolus size was reached approximately 9 hours after exposure to naphthaleneacetic acid. Branches rarely elongated more than 5 cm before their meristems died. The H. ravenii culture is maintained only by the frequent formation of new naphthaleneacetic acid-induced branches.

Full text

PDF
35

Images in this article

38Image
on p.38
40Image
on p.40

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bonnett H. T., Jr, Torrey J. G. Chemical control of organ formation in root segments of Convolvulus cultured in vitro. Plant Physiol. 1965 Nov;40(6):1228–1236. doi: 10.1104/pp.40.6.1228. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Brandes H., Kende H. Studies on cytokinin-controlled bud formation in moss protonemata. Plant Physiol. 1968 May;43(5):827–837. doi: 10.1104/pp.43.5.827. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Chrispeels M. J., Varner J. E. Gibberellic Acid-enhanced synthesis and release of alpha-amylase and ribonuclease by isolated barley and aleurone layers. Plant Physiol. 1967 Mar;42(3):398–406. doi: 10.1104/pp.42.3.398. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Dela Fuente R. K., Leopold A. C. Kinetics of abscission in the bean petiole explant. Plant Physiol. 1969 Feb;44(2):251–254. doi: 10.1104/pp.44.2.251. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Dela Fuente R. K., Leopold A. C. Time course of auxin stimulations of growth. Plant Physiol. 1970 Aug;46(2):186–189. doi: 10.1104/pp.46.2.186. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Furuya M., Torrey J. G. The Reversible Inhibition by Red and Far-Red Light of Auxin-Induced Lateral Root Initiation in Isolated Pea Roots. Plant Physiol. 1964 Nov;39(6):987–991. doi: 10.1104/pp.39.6.987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Street H. E. The ageing of root meristems. Symp Soc Exp Biol. 1967;21:517–542. [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES