do aerial roots avoid light?
 

So i had a conversation with someone about vanda roots and he told me that they grow away from light so they must not like it...i was confused bc i have thought that many orchid photosynthesize through their roots and i had never thought of vanda roots are growing in any direction at all.


I went home and looked at my vanda area and sure enough, overwhelmingly growing to the house as opposed to the yard.

BUT, i realized that this much more likely was due to the fact that the house side is cooler and thus moister and they were probably just growing to the moisture rather than away from the light.

thoughts?

Brighter yard side
https://live.staticflickr.com/65535/...c7579cb4_c.jpgPlants and animals by J Solo, on Flickr


Moist house side

https://live.staticflickr.com/65535/...f1108d35_c.jpgPlants and animals by J Solo, on Flickr

OMG what roots! Love, love, love.

I think it's more about mechanical stability than light, per se. They are climbing plants. "The tree" it climbs will be on the opposite side from the light, so it makes sense they would grow in that direction.

Plus, away from the light is more likely to have moisture that hasn't been evaporated by the sun.

Nice you mentioned this topic DC --- as only yesterday, I was looking at this.

At time 4:04

CATASETUM ORCHID UPDATE: BIG BULBS AND NEW FLOWER SPIKES/AN AFTERNOON IN THE GREENHOUSE PT3 - YouTube

That will likely be due to the mechanical/biological response --- natural movement ----- that came about naturally for survival or better orchid growth or something. Like over hundreds of thousands of years or a million years etc, plants that somehow had their roots bio-mechanically orient growth direction toward or away from something (eg. heat/light/higher-humidity or something) might have fared better - survived better. The 'natural selection' thing kicking in.

Also, for youtube videos ----- put http ..... don't put https --- to avoid issues with the orchidboard page formatting.

All very cool

I have wondered about vandas bc their roots go everywhere...in even light, if they have a directional orientation though, they do seem to lean to dark/moist/cooler side

My Cattleyas' roots usually bury themselves in the medium, probably seeking moisture. I did set a rootless one in a tiny pot and, when the roots came through the pot, lazily just put rocks in the saucer. The roots headed for those rocks, too. I should really drop that pot into a larger one.

Lol. You are really making her work for that water

In the first pic, the plants along the top of the back fence all seem to have their roots growing in the same direction, too...but no structure there that I can see to hold moisture or shade them. I am wondering what direction North would be in your pic? That might tell us if maybe the roots are growing away from the sun in the hottest part of the day?

I have Catts growing in hanging baskets, some of which have roots hanging straight down (in open air)... I have to suspect that the direction has more to do with the direction that water flows (gravity is involved) than light.

Like this...

Kind of hard to tell in a pic, but the pots on that fence all look level to me, and the one on the far left is actually tipped away from the direction the mass of roots are on??