Light requirements for different orchid plants

[Lina]

Hello. Could anyone explain why plants have very different light requirements- for example, why a vanda needs much more light than a phalaenopsis? Does vanda have less efficient photosynthesis? Or maybe it uses much more organic material to grow?
Thanks.

[Gage]

I can give you a non-scientific answer. And that is that some orchids grow in full sun, such as in the tops of trees, or in an open field. Examples: Vanda, Mule Ear Oncidium. And some orchids grow somewhere in the middle of the trees where they get dappled light. Example: Phalaenopsis. While others are all the way down on the forest floor, completely shaded from bright light. Example: Jewel Orchids.

[Lina]

Yes, I understand that it much depends on plants native growth area. But now I would be very happy to understand what are the biochemical/physiological or other differences between plants which need shade and the ones that enjoy full sun.

[opaline]

In the millions of years of evolution of which humans have only been around for a second, orchids and all plants have developed their survival genetics to accomodate the diverse habitat, climate, temperature and other variants of each continent and within the continent the further variants that exist based on altitude/ longitude, equator and the specific location within the N, E, S and W zones. etc. Reproduction further determines the complexity together with the addition of seasons that exists around the globe throughout each year. - cold to warm, dry to humid.

Every living organism primary goal is to reproduce, firstly requiring specific conditions, nutrients and food of which plants require sun to make their food. They have evolved to ensure ideal conditions are taking advantage of and non ideal conditions are avoided. Even myself generalising here doesnt even come close into the full scientific explanation.

[phytochrome]

Awesome answer...and very true...they all have their own natural dependencies...light...water...food...etc. if you can replicate their natural environment and provide their individual needs you are golden.

[Kassie]

I think the OP is looking for the scientific mechanism by which an orchid has adapted to the available light levels--something along the lines of an african elephant has large blood vessels in its ears to aid cooling and survive its climate while an arctic fox has a mechanism that constricts the vessels in its feet to avoid freezing and survive its climate. It may not be so simplistic, but after some of the discussions I've read here, I'm sure some member holds this knowledge.

[Lina]

Yes I want to know the mechanism, or at least some ideas where to look for it on the orchid.

[Lina]

Yes, Kassie, that is exactly what I want

[wetfeet101b]

To post the complete answer here would take up a large amount of text space.

I recommend reading up on the following botanical related topics:
1. Plant UV Tolerance/Dependency
2. Vapor Pressure Deficit
3. Transpiration / Trans-evaporation
4. Photosynthetic Saturation/Threshold

These (among other factors) combine to allow a plant to be optimized for their natural habitat range.

[Lina]

Thank you very much for the guidlines