Steve wrote:
Kye wrote:
.................... With or without lids???
With lids. Exactly as you will take them to your new Laminar Flow
Cabinet. When the time comes to grow seeds, you will open them there
and "install" the seeds, and reclose, right? To test the pressure
cooker, don't open them at all. If no fungus or anything grows, the
pressure cooker passed its test. Later you can test your technique in
the Laminar Flow Cabinet to see if you pass also.
By the way, I am replying based on some knowledge of autoclaves and
pressure cookers. Perhaps someone who has actually used a pressure
cooker in flasking orchid seeds can confirm what I say or add to it?
Steve
What he said... But don't tighten on the lids. Things explode if
you do that (or implode after cooling). I've only ever used a pressure
cooker for pressure canning, but the principle is the same for
autoclaves and pressure cookers. Put the lids on loosely, and tighten
them down after the media cools. If you want to add heat labile
supplements (some vitamins, for example), you need to prepare them
sterilely and add them before the agar sets. I used to let autoclaved
media cool in my flasking hood, with the lids partially off, actually.
Limits implosions and keeps condensation down (so that you can at least
see into your flasks). But you can cool them (lidded) on the counter if
you want, or if you have time let them cool down in the pressure
cooker. That will take a long time...
You don't need a laminar flow hood, but it certainly helps. And I
agree completely about testing your technique. Far better to practice
with a few flasks than make a hundred and find out you screwed up the
first step. _YOU WILL GET CONTAMINATION_ regardless. Anybody that says
they are 100% contamination free is not telling you the entire truth or
hasn't done enough flasking. Eventually, something will slip through.
The goal is to start with good technique, clean equipment, and sterile
media, so as to limit your contamination problems as much as possible.
Speaking of media recipies, there is an old one that is just
fertilizer, agar, and sugar (I think). Does anybody have a recipe for that?
Rob
--
Rob's Rules:
http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a. See rule 1
3) When one has insufficient credit to purchase
more orchids, obtain more credit