The colchicine solutions for inducing polyploidy are usually 0.25%, 0.5% or 1%, depending on species and tissue.  I generally start with the strongest solution strength.  If tissue (bud or seedling) kill is 100%, then decrease the concentration.  I hope that it is obvious that range-finding trials are necessary to determine the most effective concentrations to use.  You should NEVER treat the only plant you have.  Propagate it, then treat one of the propagules, reserving the original just in case.

TOOLS AND SUPPLIES NEEDED:

1. laboratory (safety) glasses
2. laboratory gloves (latex or PVC or equivalent)
3. analytical balance (able to accurately measure to 0.1 g)
4. graduated cylinder (or equivalent accurate measure to 10 mL)
5. (optional) micro-spatula or small spoon (able to enter vial in which colchicine powder is stored)
6. (optional) balance pan or balance paper (to transfer powder from balance to solution bottle)
7. distilled water
8. eyedropper or pasteur pipette(s)
9. small bottle with tight seal or cap (amber preferred)
10. (optional) DMSO (pure, 99.9%)
11. Dust mask, disposable, discarded after use.

CAUTION: Colchicine is a HIGHLY TOXIC POISON.  Please be prepared to handle it safely, or do not handle it at all.  Wear gloves.  Throw the gloves away after each use.  Wear safety glasses.  Wash the safety glasses after use, using CLEAN gloves.

Colchicine can be purchased from scientific supply houses as a white powder. As of January 1999, 1 g of colchicine powder sells for about $60. The colchicine gout pills listed in the PDR as a Merck product are a combo probenecid-colchicine pill.  Colchicine content is 0.5 mg.  Bill Nash (Guelph, Ontario, Canada) tells me his pharmacist stocks 1 mg colchicine tabs.  I have no information re the interaction of probenecid and plants.  But 0.5 mg is a pretty low dosage to be using for this purpose.

Pour 10 mL of distilled water into the graduated cylinder.

Using the most accurate analytical balance you have available, and transferring the powder using a microspatula, measure 100 mg (0.1 g)
colchicine onto a clean piece of balance paper, or into a clean disposable balance pan.
[per KL] Microspatula is not needed if you practice tapping out small amounts of powder (practice with corn starch).
[per RG] This is good.  A steady hand and practice works here just fine. Kay has good lab skills!

Transfer the colchicine powder from the paper or pan into the small bottle.
[per KL] A square of wax paper works well for this.  Even better, weigh directly into a beaker.  The little disposable medicine cups that
pharmacies have are very good for this (they also come packed with Nyquil).
[per RG]  Good suggestion.  If the disposable cups are available, and the balance can be tared easily, then this is a great idea.  We use the disposable balance pans just like Kay suggests for the Nyquil cups.

Alternatively, if you're working with a good balance, tap X amount of colchicine into the container you'll be mixing in.  Weigh it.  Figure the amount of colchicine you'll need (say you got 53 mg of colchicine into the container: add 5.3 ml water for a 1% solution)

After rinsing the paper or pan, dispose of the paper or pan so that it cannot be re-used.

Carefully rinse the powder dust from the paper or pan into the bottle, using some of the previously measured distilled water, and an eyedropper or pasteur pipette. I'd dissolve the colchicine in half (roughly) of the water, transferring that solution to the storage vial, then use the rest of the water to rinse the mixing container, adding that to the solution in the storage vial.  Cap and shake.  The colchicine powder is highly water-soluble, and should go into solution quickly.

The measurements above will give you a 1% solution.

[per KL] 100 mg/10 ml is the same as 0.1 g/10 ml is the same as 1 g in 100 ml, or 1%.

To make solutions of different concentrations, use these amounts:

0.5% solution: 50 mg (0.05g) colchicine, 10 mL water
0.5% solution: 500 mg (0.5 g) colchicine, 100 mL water
0.5% solution: 5 mL 1% solution, 5 mL water

0.25% solution: 25 mg (0.025 g) colchicine, 10 mL water
0.25% solution: 250 mg (0.25 g) colchicine, 100 mL water
0.25% solution: 5 mL 0.5% solution, 5 mL water
0.25% solution: 5 mL 1% solution, 15 mL water

BE CAREFUL.  DMSO enhances penetration through HUMAN tissue as well as plant tissue.  If you are using a DMSO-enhanced solution, you should use DOUBLE gloves (wear TWO pairs).  DMSO if it gets into your system, will produce a
garlic-ey taste in the back of your throat.  By itself, that's not a problem: people rub it into their skin as a home arthritis treatment.  NOT
to be recommended BTW.  But if you taste garlic when you are using DMSO-spiked colchicine solutions ...

Discard all used disposable items. Carefully wash all others, wearing gloves. Wear clean gloves when washing safety glasses.

The bottom line is BE CAREFUL.  If you are not familiar with how to safely handle poisons --- DON'T DO IT!

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