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Abgeschickt von Holger Perner am 19 April, 2004 um 12:24:51
Antwort auf: Cyp. calceolus flasking media and chlorine treat von Jim Rowley am 17 April, 2004 um 02:06:47:
Although you didn’t mention it but from mentioning to order from an American company I conclude you live in North America, so I think you don’t mean Cyp. calceolus but some form of Cyp. parviflorum (varieties pubescens, makasin or perhaps parviflorum which is pretty much like pubescens except that it grows even drier and has smaller flowers with brown sepals and petals like the moist-growing variety makasin). They are easier to germinate than Cyp. calceolus, a species from Europe and Asia that has only the color in common with the American „yellows" and is nearly impossible to germinate from ripe seed.
I would say choose between the two casein-containing media offered by Phytotech. Potato chippings are a good idea, but the amount is open to your experiments. Bill Steele is using a certain cultivar of potato that insures repeatable results, other cultivars might influence the medium differently, so try anything between 0.2 ccm to 4 ccm or so per 50 ml medium.
5 % Chlorox is relatively equal to 0.3 % NaOCl (I think Chlorox contains 6 % NaOCl). I write relatively because Chlorox is not just diluted NaOCl but contains some other ingredients not fully disclosed on the label. However, it is „orchid" proved and widely used elsewhere in tissue culture, so it is fine. As you already understood, the main reason to treat Cypripedium seed with bleach is not to disinfect it (just a „side effect") but to destroy the inhibitors in the inner seed coat around the embryo that prevents the embryo from germinating freely. The structure and composition of this seed coat as well as its contents varies from species to species (and of course also in parviflorum between the botanical varieties) and from seed batch to seed batch, so again a broad field for trial and error. With your weak bleach something above one hour would be an option for pubescens, with the more usually used 0.5 % NaOCl (which translates to about 10 % Chlorox, the 0.1 % mathematical difference is not so important: Chlorox and all other bleaching solutions are loosing bleaching capacity over the time and nobody ever mentions the fabrication date of the stock used for the bleach, so more or less extreme ambiguity is the norm in all bleaching recommendations) some 60 minutes or so would be good and some 30 % less time for makasin. But these are just suggestions.
Don’t try to acidify the bleach, this is very dangerous to your health because acids applied to hypochloric solutions release chlorine gas that not only harms (or kills) germs but you too!
Any pH of the medium between 5 and 6 should do. Pineapple is also fine with Cyps but if you already use potato adding extra „none-defined" components with natural plant growth regulators as pineapple juice is not recommended. The commercial medium should already give a pH in the adequate range so pineapple juice for lowering the pH is perhaps not necessary.
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