carrot starch

Douglas P. Jensen jensendp at DIANA.HOLLINS.EDU
Thu Sep 18 08:13:09 EST 1997


Hello all, 
        I am prepping a lab on roots today, and I had wanted my students to
stain carrots for starch using I2KI.  I assumed there would be amyloplasts
in the carrot, but the carrot did not stain.  I tested it on a potato, which
turned nearly black immediately, so I know the stain is fine.
        I'm wondering: (1) Is the starch possibly in a form in the carrot
that iodine will not stain?  (2) Are carrots harvested for the grocery store
BEFORE the sugars are polymerized into starches?  If so, is this something
that carrots are selectivly bred for?  Perhaps then if I find a queen anne's
lace, I could stain its root with positive results.  My students sure
wouldn't mind a trek if the weather cooperates.
        I recall how every so often, I buy carrots and a few or event the
whole bunch is nasty and woody.  I always thought these were second-year
carrots.  Perhaps they are merely harvested too late.

Anyone have experience with this?

Doug 

Douglas P. Jensen, Assistant Professor of Biology
PO Box 9615
Hollins College
Roanoke, Virginia 24020
(540)362-6549
jensendp at diana.hollins.edu




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