Paph. cell collapse

[LJA]

Julie emailed me a pic of a couple leaves on her HF, and while I know *what* it is, I'm not very clear about what *causes* it. Cell collapse or mesophyll collapse leaves a wide, sunken area in foliage, and I've only noticed it on multifloral paphs, never anything else. When the plant is exposed to high light, the sunken area is the first to start looking crispy.

This isn't fungal or bacterial, and when I emailed Tom Larkin and asked him, he thought it might be caused by excessive light damaging the leaf's cells and causing the sinking, but he wasn't sure.

Have any of you Paph folks seen this on your plants and know what the cause might be? Any help with this would be greatly appreciated....

[TundraKev]

I always thought a common cause of this was very cold water damaging the cells on the leaf surface. They die and collapse.

[paphman910]

I have a paph wilhelmine that does that on the older leaves. I seem to happen when my Paph wilhelmine are going thought cycle of complete dry and wet cycles. Other than that I do not know what causes these symptoms.

Paphman

[uncasteeb]

My Paph supardii seems to be prone to the same , i,ve moved the plant to slightly less light but it still seems to happen.It,s growing stronly & producing new leaves so i,m just going to let the plant get on with it.
I would love to know the cause.

[Piper]

Well, most of the leaves collapsed and were only later browned, so I think Louis is right that the scorching comes from too much light to vulnerable leaves. But is the collapse a sign of too much light itself?

The plant is getting a lot of indirect light all day long, but not much direct (and we're north so our light isn't as strong. My phals and onc's get as much.

I'm always trying to cheat the paphs and phrags (particularly the multi-florals) into more light, because I thought they were more light loving. Am willing to bet it's too much, so it's gone into the less light room.

Louis, could you rate for me how much relative light your sub-genera get at RVO? Your plants are so perfectly healthy. The SA phrag was in the same light as the paph HF with no problem. It even has a new growth. Maybe a relative indication would help (since I have a number of plants from you.)

Kev, I water with lukewarm water, so that's not the prob. Plus I dip my paph pots. The leaves never get wet.

Julie

[mde]

The timing of this post is uncanny. I've just had two Phal.s do this (looked EXACTLY like the leaves in the photo, and they got to the point they looked so bad, I just canned them.) Since I have a horrible record with Phal.'s, I just assumed it was my curse. I didn't even consider light as an issue with mine as both of the ones in question have been in the same light for 1 1/2 years, including two bloom cycles. I had recently repotted them after noticing a few rotted roots, and it was about 3 weeks later that this occurred. I assumed they had been overwatered and it was rot? All of my water is kept at the same temperature too, and I never get it on the leaves anyway, so I also hadn't thought water temperature could have caused it. Am interested in reading/learning more about this process so I can possibly prevent it in the future.

Matt

[RSJ]

I have experienced this with a phal. Just as you described, cell collapse which doesn't do anything else unless it gets exposed to high light and then it turns brown and dry.

I was wondering, based on the placement of this phal in my office, if it's dry and warm fan air directly on the leaves?

RSJ

[TundraKev]

Julie

I just threw out that idea because of a discussion on another forum concerning the same thing. From what you've said, it does sound like a light issue. Either way, when the outer cells of the leaf are damaged, it looks like that kind of collapse can occur. It makes sense.

On this other forum, we were once discussing why a person was having problems with spikes on phals suddenly collapsing. It turned out that water condensing on the roof of the GH was dripping and hitting the spike on one spot. Since it was winter at the time, the water was cold and caused the same kind of cell collapse on the spike.

[mde]

I just realized I still had one of them in the trash, so I pulled it out and took a photo for reference. It looks like the same process to me, no?

Matt

[TundraKev]

It looks like some kind of damage to the surface of the leaf. I would say the same thing.