How do seed cells know the difference between top and bottom?

Ross Koning koning at ECSUC.CTSTATEU.EDU
Mon Apr 21 13:36:27 EST 1997

At 1:03 PM -0400 4/21/97, Nanda Somarajan wrote:
> Tropism is just tendency of any organism towards something.
>There are other tropism, including towards light and certain chemicals.
>Many single celled animals that produce their own energy by
>photosynthesis does both light and chemical tropisms.

Rather than "trop-" (bending), in this last case
we usually use "tach-" as in phototaxis or chemotaxis
to indicate the fast locomotion rather than shape
distortion.  So moss sperm are called chemotactic
as they swim up a concentration gradient of chemicals
to arrive at the egg.


Ross Koning                 | koning at
Biology Department          |
Eastern CT State University | phone: 860-465-5327
Willimantic, CT 06226 USA   | fax: 860-465-4479

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