At 6:59 AM 1/14/97 -0800, Alyson Tobin wrote:
>Does anyone know of a good, simple, stain for lipids in plant tissue? Our
>students are looking at seed storage reserves and comparing oily and
>starchy seeds. In the past I have got them to cut seeds in half and add
>Sudan III to stain for lipids. It is very difficult for them to see the
>staining as Sudan is red and a positive test is the formation of a dark red
>stain on the tissue- hard to see against a red background of dye. Any
>suggestions?
I have always used dilute Sudan in an alcohol base.
If the seed is crushed slightly under the
coverslip, observed, then the Sudan pulled
through the mount with a paper towel (in the
usual way), the Sudan will be taken up into
expressed oil droplets and accumulate strongly
there. The background is only very faintly
pink but the droplets become intense red. If
the seed is too tough for crushing (I use plastic
cover slips!), or too large, you can slice it
thinly with a razor blade first. Uptake of
Sudan into the tissues is more chancy, I find,
so expressing the oil with some pressure does
the trick. It also gives them some idea about
how we get vegetable oil for cooking from oilseeds.
ross
______________________________________________________________
|
Ross Koning | Koning at ecsu.ctstateu.edu
Biology Department | http://koning.ecsu.ctstateu.edu/
Eastern CT State University | Phone: 860-465-5327
Willimantic, CT 06226 USA | Fax: 860-465-5213
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Plant Physiology is Phun!
/\|___/\ //\______COOH NH-CH2-CH=C-CH2OH \/OH
| | | | | | || //\___ \CH3 /\|/\\/\\COOH
\/ \/|\/| \\/ \ / N || N | |
/\ | |__|= NH | || || //\//\
| COOH \\ /\ / O
COOH H2C=CH2 N NH
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