Reddening Protocorms in Replate Flask?

[Royal]

I know someone here can help. I have some protocorms with about two leaves, that are turning red in the replate flasks. The mother flasks still look great (nice and green) so I don't think they are 'browning out' but may be suffering a deficiency? The color just started to appear once replated. It's not on the leaf margins, but is affecting the new growth, so I don't think it's a lighting issue. The area in contact with the new media is fine, but the tops of the p-corms and the youngest growth is affected. It's not contamination (I'm very familiar with what that looks like )


Any help is appreciated. Oh, and it's not a picky or iron-needy species, just a hardy old Encyclia.

[Orchidaholic]

I'm not sure but I would guess it is a lighting thing. Just basing that on my observations with freshly deflasked plants and mature plants. Cattleya's older growth will stay green but the new growths will come out purple when light is increased. My Aerides seedlings turned red/purple from less wattage but more spectrum (both visible and UVA-UVB). Just my guess but there is always the possibility it is something else.

[Royal]

Thanks for the reply. I did move the light about 6 inches further away last night, just to eliminate that possibility. You are probably right.

The red color isn't on new growth vs old growth. It is on the tops of the protocorms and on the leaves, but toward the mid-vein of the leaf in the 'crown' of the shoot. The leaf margins are green still. It is my experience that coloration from hight light is usually most evident at the edges or margins of the leaves. That's why this is kind of baffling me.

[Royal]

Nobody else, huh?

[Orchidaholic]

It's summer, everyone must be on vacation!!!

[adriponic]

Royal

Hard to say without seeing. I note one thing, the color
change started immediately upon replating, this is not in
my opinion a deficiency which would take some days before the p/corms showed it. Light? there again there should have some time before the p/corms reacted,
besides the mother flask is ok and probably under the
same light?

Have you disinfected the protocorms upon transfer?

Some 29 days have elapsed since the transfer - what is
the status now?

Yours answers might give me a clue.

[Royal]

Originally Posted by adriponic

Have you disinfected the protocorms upon transfer?

Some 29 days have elapsed since the transfer - what is
the status now?

Ahh, your questions got me thinking. Yes, some were disinfected for replating. As a result of opening the mother flask for the first replate, the mother flask was contaminated. I caught it early and while still very small, so I attempted to salvage the unaffected p-corms. I removed most of the p-corms leaving a margin around the contamination, agitated them in a 1 in 24 bleach solution, then a rinse in plain RO. They were then replated. Success!!! No contamination anywhere. (ps Just as an experiment, I tried removing the colony from the flask to see if that would work. It didn't)

All that being said, I think it's the light. Not all that showed reddening were salvaged from that contaminated flask. Some were from a different mother flask and replated at different times. My mother flasks are baby food jars - opaque lids. But I replated in a horizontal flask for more surface area, so they were getting more intense light even though the light hadn't changed. I moved the light a bit after getting some tips here, and that seems to have taken care of it. A few are still affected, but I think they are going to green up.

Adriponic, You raise good points regarding the time it would take to show deficiencies. Thanks for the help! I'll try to post a picture or two. I'm seeing good root growth and shoot elongation, so I think all is well.

Thanks to you all!

[adriponic]

Royal

I would agree that sudden change in light intensity ( in your case must have been at least fourfold) can induce redening of p/corms clumps.

I have a fellow worker who had many unexplained necrosis in his replates and decided to enquire how he was replating. So I sat in front of the laminar flow hood watching him replating. He picked out clumps from the mother flask and sorted them inside a petri dish and occasionally sprayed the p/corms with a 3% hypoCl as a precaution. When the mother flask was empty he started replating smartly and evenly by importance of size. I stopped him then asking him to proceed with another mother flask, but this time not to spray the p/corms.

I did not have to wait for long - 4 days later the replates which were sprayed were all showing signs of necrosis and the ones which were not sprayed were all doing well.

In fact what happened was that the p/coms were not disinfected at 3% hypo. In the 5 to 10 mins from sorting to replating the concentration had increased to over 50% because of the tremendous rate of evaporation of water from the solution under the airflow. Just spary 3 to 4 dashes of water onto a petri under the airflow and wait for 10 mins ... the petri dish surface is almost dry by then.

Hope you find that interesting.

[newflasker]

There is no doubt about light changes the color of orchid leaves. I changed my light bulbs to have more spectrum and more brighter then color of mature-plant leaves turn light red. Moreover, it's depend on what kind of orchid you grow. I got 3 different Phal seedlings from sowing. When they grow up one turns red but 2 don't. They are in the same incubator in the same condition. Good news, I don't see anything wrong when they turn red (maybe a little bit better). Hope to hear more from members. Cheers.

[Royal]

Normally I don't use anything on the plants during transfers. Just scrape a few p-corms and drop them onto the replate. No disinfectant. I just thought I'd try to salvage the one with contamination. I've been told it was a futile attempt, but I just had to try. I definitely learned something, and it worked!

I'm thinking I'll try to get my hands on some magenta B-caps for my mother flasks. Maybe a little more light from the start would be less of a shock. I guess I could just raise the light fixture up a bit. I may try both.

Thanks again to you all!