Dear Bob and Colleagues,
I've done carrot tissue culture several years in my plant phys course.
I
can tell you what culture media I use, but I only generate callus from
the
carrot tissue, because I use other things for generating shoots.
Usually
the callus begins to produce anthocyanin and that lets us talk about
tissue
differentiation, gene regulation, etc. Plus it looks really cool.
I use the Murashige and Skoog basal salt macro and micro salt
formulations,
purchasing the 10X concentrates from Sigma. I make up my own organics
and
hormones, but having the salts ready to go is a huge time savings. The
recipe I use is Murashige and Skoog, 1962. I believe Sigma gives the
citation, but it has been reproduced all over the place. If you can't
get
hold of it let me know and I can fax you my version. It's too much
typing
to do in an email. By the way, I found it really makes a difference to
use
the carrots with their green tops still intact. These are usually
fresher,
I think, than the pre-bagged carrots without tops, and have responded
much
more vigorously.
For shoots I use African violet leaf pieces. I have African violets in
my
office, so a ready supply is easy. They generate lots of little shoots
very nicely, and with any luck by the end of the semester students can
cut
off their resulting shoots and root them in a little potting mix to take
home. Again, M&S media works fine, using the shoot inducing hormone
formulation.
Lastly, I also have the students do embryo culture from corn seeds. I
got
this exercise from Bill Pietraface at SUNY Oneonta, and it works
great. The culture media is still M & S, but without any hormones. You
get a fresh ear of corn (usually available at the grocery even in
winter),
surface sterilize the seed, and then squeeze out the embryo. The
embryos
starting growing right off, and the students can culture fresh corn
seeds
too and see that the intact seeds do not germinate at all. That leads
to
discussions about why.
I often have this tissue culture exercise over two lab periods, with the
students learning how to make solutions and preparing the media for
themselves in the first period. The second period they initiate their
cultures, and then we observe them over several weeks. This has always
been a very popular exercise that works well, and generates many kinds
of
teaching moments. A very handle little book that gives various tissue
culture recipes and tips is "Experiments in Plant Tissue Culture" by
Dodds
and Roberts. I got the African violet procedure out of there.
Good luck,
Kathleen Archer
At 01:33 AM 02/14/2003 +0000, you wrote:
>I am looking into having my plant physiology students culture carrot
>tissue. Sigma lists a number of different pre-made media from which
>to chose. Does anyone have suggestions regarding which medium might
>be best for carrot callus growth and which would be the choice for
>carrot shoot regeneration from callus?
>>Bob
>---
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Kathleen Archer
Dept. Biology
Trinity College
Hartford, CT 06106
Ph: (860)297-2226
kathleen.archer at mail.trincoll.edu
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