What REALLY causes root death?

[ScottMcC]

I think that understanding root physiology is definitely complex, and I think one of my main goals of this discussion was to get beyond the simple "overwatering causes root rot" truism and really take a look at what's going on in the root. in that regard, this thread has definitely been a success.

anyway, continue the discussion! surely there's more people who have thought about this issue!

[jmce96]

Originally Posted by littlefrog

An old vanda grower's trick (some people may still do this) was to take a floral pick (like a single rose comes in), fill it with stale beer, and slip it on over a big vanda root. Supposedly this gave the plant a boost. Maybe it got the plant drunk, I don't know. Tried it once, but I was never a good vanda grower.

The roots did eventually die, I think...

I don't know where the full water adaptation comes from. Plants are remarkably adaptable, though.

*hi, can someone explain me this more clearly? because i saw it in a book a few months ago but i have never been able to understand it, i have a renanthera in my GH an it has a lot of roots, its about to bloom, is a nice and healthy specimen, and i would like to experiment with that thing of the beer

[King_of_orchid_growing:)]

Originally Posted by jmce96

*hi, can someone explain me this more clearly? because i saw it in a book a few months ago but i have never been able to understand it, i have a renanthera in my GH an it has a lot of roots, its about to bloom, is a nice and healthy specimen, and i would like to experiment with that thing of the beer

Your Renanthera is growing well, why would you mess with success?

I really can't recommend you doing such an experiment, especially when the risks far outweigh the rewards. What would be your purpose? You don't have problems growing it at all!

In this hobby, I can safely say through experience, if it isn't broke, don't touch that dang orchid!!!

[harleymc]

I'm not sure how the edema theory stands up. As water flows into a plant cell the cell wall and membrane will extert increased pressure slowing the osmotic differential. Furthermore there would be water moving to the other parts of the plants, stem, leaves, flowers so if the problem is osmotic pressure then it would be expected that the entire plant would collapse simultaneously.

Nature has already done most of the experiment for us. In the tropics it can rain continuously for days on end. The orchids don't explode there.

[orchidsarefun]

I think ( maybe in a roundabout way ) that we are breeding into our orchids those characteristics that we find desirable and which may not be evident in the "wild" or in the original species. So, invariably, a plant with good flowering form/ spikes, will have a good rooting support system ? And maybe the converse is also true ? Not every plant selected for breeding will have good roots. Sounds strange but I have 2 phals that have very poor roots, new roots are plentiful and healthy but are growth stunted. The plants have attractive flowers. They need additional care, irrespective of medium I have tried to grow them in. I have also seen photos of other big box orchids with a similar problem.
So - because of hybridisation/genetic manipulation -is it possible to be exact about causes ?
I read somewhere that some growers are concerned about the genetic diversity of many orchid species as even those that are harvested from the "wild" are not as genetically diverse as about 50 years ago. I am trying to tie genetics as a major factor into root growth/death.