Phal Germinating Seeds turning Black

[DozerDC]

Hello all - first, thank you to all the forum users and posters here as I have found this forum to be a wealth of information as I continue my adventure in orchid propagation from seed. This adventure has been so much fun despite tons of set backs and failures.

Using this forum, I also think that I know the answer to my question: why are my precious little babies turning black? I tried to get a good picture; the attached isn't very good.

I flasked some phal seeds back during the eclipse on August 21st. There was no contamination in the jars but now just as the seeds are now turning green and little roots are visible with the help of a magnifying glass, some of them are turning black - I should say the agar underneath of them is turning black. I assume this is not good as it isn't a dark green, but is just black. Death black. Reading on the forum here people seem to indicate that it is a reaction to phenolic compounds that the protocorms are producing.

If this is indeed the issue how can I prevent this? I read some people say to mix activated charcoal into the agar. But then some people say that isn't true and that it won't help. So I would love some verification. If the charcoal will help, can someone be kind enough to point me to the right charcoal? Also, I read that if you add charcoal to the agar that you have to do special steps to prevent the charcoal from settling to the bottom of the jars. Lastly, is there anything I can do at this point to rescue this batch?

Thanks!

[jkofferdahl]

From where did you obtain the seeds? Virtually all seeds sold online as orchid seeds are not.

[DozerDC]

Howdy! I harvested them from a phalaenopsis of mine.

[jkofferdahl]

Originally Posted by DozerDC

Howdy! I harvested them from a phalaenopsis of mine.

Excellent.

[dansyr]

There are many more expert than I on this forum, but I can confirm that unhappy protocorms do leach out some compounds that turn media dark (my main enemy when trying to do leaf sections...grr). That being said, I can't quite tell what's going on from your image very well, but I'm guessing theres lots of little normal looking tiny bump spikes and a couple little black/dark grey patches spread around, probably where its most dense? Your media looks kind of different though... is this a home-brew media or just a very brown P668/MS?

I generally use some charcoal in my media, to varying degrees, just because it makes transplanting easier. If I have PGRs in the media I definitely notice a drop in impact with charcoal, but if I keep the charcoal really low (like 0.01-0.02% kinda low) I still get some PGR activity without having to passage the culture every week or two. If you get the good charcoal (like Sigma's) you shouldn't have too many problems with it settling out since it's pretty fine and stays suspended fairly well if you pour when it's at like 40-50 degrees C.

For rescue, I've found rescuing individual protocorms/calluses that blacken to be virtually impossible, but removing the already dying and reducing crowding on a plate definitely helps reduce the occurrence/spread of blackening.

[DozerDC]

Hi, Dansyr. Thank you very much for your reply. I am sorry for the poor picture - it is so hard to get a decent image because of the glass. I even tried taping a jeweler's lens to my iPhone to take a picture - that was equal parts comical and failure. But you are pretty spot on with your assessment of the situation, although I am not sure what you mean by bump spikes. At this point, I only see the seeds turning green although today I do notice one looks to be growing taller. There is a sea of little, greening seeds now speckled with darkening spots.

The medium is a home-brew so it could be that I messed that up (it has no charcoal in it). But, I can make a new batch with charcoal. I may even just do that to practice even though I have no more seeds at this point. Also, thank you for the name of a good charcoal; that removes another variable of me getting the wrong kind, etc.

Honestly, even if I lose all the flasks (4) at this point I am still ecstatic that I made it this far. I realize there are thousands of people who have done this but it really is an enjoyable adventure.

[dansyr]

Dude you should be totally proud of yourself for getting this far. And I would be very surprised if you don't get any seedlings out of this... seems like you've been doing things right. You will definitely lose some along the way but that's just life.

I think homebrew media should be fine, I've never used it and was just concerned if it was MS or something like that, then theres definitely something going wrong. But sounds like it's all good on that front.

Don't feel bad about photographs, I have the same exact problems with photographing through glass...it's so annoying. I am always amazed when people show these perfect photos of stuff inside bottles. HOW????

[PaphMadMan]

The black discoloration is probably phenolic compounds. It is a sign of stress in plant tissue culture. Since your protocorms have probably not had physical damage it could be promoted by a nutrient imbalance, incorrect pH, high osmotic potential (too much sugar or nutrient salts), high temperature, too much light, many things. And once the phenolic compounds begin to accumulate they add to the problem.

Since your media is a home brew, I'd lean toward salts content and pH as the place to start - probably reduce total salts and sugars in your next batch unless it is already low, and at least check pH to see if it is in a reasonable range - and buffer if it isn't. Addition of charcoal may help, as well as adding an antioxidant such as vitamin C to the media.

Treatment at this point is problematic. Remove the dead or dying tissue if you can and hope. Good luck.