What causes new growths to be purple/red instead of green?

[lotis146]

Originally Posted by tropterrarium

AFAIK, it is a question of pigment development in the new growths of many plants. The red xanthophylls develop first/in greater concentration than the green chlorophyll. Absolutely normal and nothing to worry about.

So what about when the red pigment comes later, is that more likely a sign of sufficient light levels or...no one easy answer perhaps?

[tropterrarium]

In general, plants have both chlorophylls and xanthophylls, both are part of the larger photosynthetic machinery (reaction center and antenna pigments). The color we observe is the result of the ratio between those two (more?) classes of pigments.

It seems to me, that the changes in composition during development of organs is specific to a plant species. Many plants (monocots/dicots) have young parts that are red, mature ones turn green. Some go straight to green (e.g. pleurothallids). The deeper reason behind that eludes me as well. I only got a C- in plant physiology!

Fall colors (yellow/red) is basically the same, just in reverse. The chlorophyll with its Mg center gets recycled/stored, the xanthophylls are left over giving an overall more yellow-red appearance.

[Laserbeak]

Different types of chlorophyll cause the different colors. That occurs probably because the new growths haven't gotten the light exposure the mature areas have.

[RJSquirrel]

What causes the red pigmentation in the plants is anthocyanin.

Anthocyanin pigments are responsible for the red, purple, and blue colors of many fruits, vegetables, cereal grains, and flowers. They have long been the subject of investigation by botanists and plant physiologists because of their roles as pollination attractants and phytoprotective agents.

When your plant is getting the optimal light levels the anthocyanin reacts to the light and causes the blotching for sunscreen. Tender growths need a lot of protection from high light right?. Makes perfect sense for protection of the tender young plants. If your new growths, leafs, bulbs etc etc were not getting the max light, they might just be a shade of green without the phytoprotective agents ever showing their coloration, but healthy all the same.
I have 2 Blc growths that came out and they are black they are so dark red. If you didnt know it you would think they are dead. They are not dead and should bloom some very nice flowers maybe in 6 months....

All plants have their own levels of this and the conditions are not the same for us all. Each plant will react differently according to the culture techniques used.

[ramonypony]

Thanks everyone! I guess I will leave them where they are since it sounds like they are getting enough light there.

[lotis146]

Here's my own example of this:

This is one of my twin Phal keikis (the other produced a spike over a month ago). As you can see the new leaf is coming in very dark. Whereas a mini Phal not even 2" behind it on the shelf has a new leaf coming in that is bright/light green, and yet another mini not 2" behind that one is growing two new leaves at the same time and they are both green. The keiki is the closest to this east facing window.






This is the 2nd mini, and yes it has suffered neglect a couple of months ago so I'm quite happy to see its two new leaves.

[ramonypony]

Originally Posted by lotis146

Here's my own example of this:

This is one of my twin Phal keikis (the other produced a spike over a month ago). As you can see the new leaf is coming in very dark. Whereas a mini Phal not even 2" behind it on the shelf has a new leaf coming in that is bright/light green, and yet another mini not 2" behind that one is growing two new leaves at the same time and they are both green. The keiki is the closest to this east facing window.

Attachment 101323

Attachment 101324


This is the 2nd mini, and yes it has suffered neglect a couple of months ago so I'm quite happy to see its two new leaves.

Attachment 101325

lotis, I have several new phal leaves growing as well. Two phals sitting right next to each other each with a leaf growing, and the one with the smaller leaf is completely green while the bigger one on the other plant is still somewhat purple. In my experience with phals the more trauma they've experienced, e.g. roots loss, crown rot, etc. the more purple their young and mature leaves will get. And once mine have recovered they return to green. I've always heard that purple or red coloring means that the plant is receiving enough or too much light but don't think that's all there is to it.

[lotis146]

Originally Posted by ramonypony

lotis, I have several new phal leaves growing as well. Two phals sitting right next to each other each with a leaf growing, and the one with the smaller leaf is completely green while the bigger one on the other plant is still somewhat purple. In my experience with phals the more trauma they've experienced, e.g. roots loss, crown rot, etc. the more purple their young and mature leaves will get. And once mine have recovered they return to green. I've always heard that purple or red coloring means that the plant is receiving enough or too much light but don't think that's all there is to it.

I don't either. Interesting that you say that though because as you see the plant that has experienced the most trauma is actually the one with the green new leaves (two at the same time) not the one with the darker new leaf.

[ramonypony]

Originally Posted by lotis146

I don't either. Interesting that you say that though because as you see the plant that has experienced the most trauma is actually the one with the green new leaves (two at the same time) not the one with the darker new leaf.

Hmm, I see that. I've seen it happen with mature leaves on suffering plants, the leaves will shrivel and also get a purple tinge and if there's a purple baby leaf it becomes even more purple. I think the health of the plant and the amount of light both play a role, something to do with the pigments. I'm sure there's a scientifical reason but I don't know, that's just what I've seen happen. I have some phals that I've never seen any purple on no matter how much I've traumatized them.

[RosieC]

Originally Posted by JMNYC

Only two Catts?

I am now dying to know, what alliances are you moved to?
(This is always wonderously individual-specific; I just love that.)

I've not been successful getting Catts to flower yet, grow well yes, but flower no. So haven't bought more until I feel more confident I can flower them.

I grow quite a mixture of other things. Masdies, Phals, Paphs, Phrags, Cyps, Oncidiums, Dens and some bits and pieces of others.