C-Fern Logo  C-Fern
C-Fern Home
Web Manual
  C-Fern Nutrient Medium
  Culture Conditions
  Gametophyte Culture
  Gametophyte Observations
  Sporophyte Culture
  Spore Mutagenesis

Other Resources

  Light Stand
  Growth Pod
  DNA Extraction
  C-Fern T-shirt
  Who's Who
  Selection and mutants
  Media formulation error
  Image gallery
Web Journal
Educational Resources
  National Science Standards
  Gametophyte development
  Student research questions
  Research in the classroom
  Research with C-Fern
  Brief description of C-Fern
  C-Fern manipulation
  Root tropism?
Frequently Asked Questions
Workshop and Exhibit Schedule
 Educational Materials
  Mutant & wild type spores
  Manual & Culture Instructions
  Supplies - Domes, media
Have questions?
Contact the C-Fern Project
 Supported, in part, by the National Science Foundation - Division of Undergraduate Education
Development of C-Fern is supported
by the National Science Foundation (NSF-DUE)
Copyright © 1997-2000
Thomas R. Warne and
Leslie G. Hickok.
All rights reserved.

Teaching With C-Fern

C-Fern: Root Tropism?
The Brief Story Behind the Question

L a b  C o r e
Description of the Model System
Equipment Requirements
Sources for Spores & Culturing Supplies
Research in the Classroom
Research Questions
C-Fern Technical Assistance
L a b  L i n k
Background Web Links
Adopter Links
Research Links
On-Line Poster Presentations
Discussion Board
Unlike animals, plants have limited power of movement and therefore respond to environmental stimuli in other ways. Major stimuli, such as gravity, light, and "touch" can produce a postive (towards) or negative (away from) response in plants by means of differential growth, in which different groups of cells increase or decrease their growth (elongation) in a way that reorients the plant part with respect to the direction of the stimulus. In C-Fern, sporophyte roots typically exhibit the standard positive gravitropic response. However, especially in dense cultures standard cultures grown under standard culture conditions (constant light and temperature) yield sexually mature gametophytes in about 2 weeks. If these cultures are watered once to effect fertilization a large population of synchronously developing sporophytes are produced. Over the next two weeks (primary) roots from these sporophyte elongate and begin to grow towards a "focal" point within the culture media.

Your job is to explore, confirm, explain, or elaborate on this tropic response!


  Root tropism in C-Fern
  C-Fern sporophytes - top of Petri dish C-Fern sporophytes - bottom of same Petri dish. Note directional growth of roots towards a focal point in the center left
  • What is this tropism?
  • What other tropims are evident in C-Fern?
  • Is this repeatable phenomenon?
  • What conditions encourage/discourage this response?
  • What is the pattern of root development?
  • What is the origin and fate of the first C-Fern roots?
  • How do later roots arise?
  • Is there a good way to measure and quantify this response?

Questions for Independent Student Research

Return to Research in the Classroom

C-Fern Educational Materials are available through Carolina Biological Supply Company, P.O. Box 6010. Burlington, NC 27216-6010 at 1-800-334-5551. For Technical Support, questions about products or their use contact 1-800-227-1150.