>From jperry Sun Mar 3 18:12:28 600 1996 remote from foxy.uwc.edu
Date: Sun, 3 Mar 1996 18:12:28 -600 (CST)
From: Jim Perry <jperry at foxy.uwc.edu>
Subject: Re: Onion root tip squash
To: bmcnulty at oavax.csuchico.edu
cc: plant-ed at net.bio.net
In-Reply-To: <4h7em5$1el at charnel.ecst.csuchico.edu>
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On 1 Mar 1996 bmcnulty at oavax.csuchico.edu wrote:
> I am looking for a simple protocol for squashing and stianing onion
> root tips. We would like to do this in an introductory course so the easier
> the better.
>> Thanks
> Bob in Chico
>>Hydrolyze the root tips in 1N HCl that have been previously fixed in
acetic alchol (3 parts 95% EtOH + 1 part glacial acetic acid) at 60
degrees C for 8 - 10 minutes. (Rinse the root tips in dH2O before
hydrolyzing.) Wash the hydrolyzed roots thoroughly in d H20 just before
use. Stain with acetocarimine (1g carmine + 45 mL glacial acetic acid +
dH2) to make 100mL): Mix acid and water then bring to boil; dissolve
carmine in th eboiling 45%acetic acid; cool and decant; add 2 drops of a
saturated aqueous solution of ferric acetate and allow to stand for 24
hrs; filter and store in a refrigerator. To stain, place the root tip on
the slide, add a drop of stain, a coverslip, and the press down on the
coverslip to squash the root tip. Heat the mount by passing over a flame
(don't boil away the stain!) or use a hot plate. OR, buy Schiff's Reagent
for a stain.
Onion root tips work, but the chromosomes in Narcissus roots are much
larger.
Both onion and Narcissus go thru a diurnal cycle of cell division. You'll
get many more mitotic figures if you cut and fix the root tips at noon.
Jim Perry
UW Fox Valley
Menasha, WI 54952-8002
jperry at uwcmail.uwc.edu
