Some shaking can encourage growth - thigmomorphogenesis. We published some stuff some years ago (from David Hepworth's thesis) using transgenic tobacco plants with one of the three lignin pathways knocked out. When the plants grew in the greenhouse there was no difference between control and transgenic in terms of shape, but the transgenic ones had more floppy stems. If you grew them without support, and sprayed them with water, hard, for a few minutes each day, the transgenic ones were shorter with a larger diameter stem, but exactly the same flexural stiffness as the controls. I sometimes use this story to show that plants have a self-image and are therefore conscious!
Presumably this means that a few minutes shaking doesn't matter to much in terms of physiological health, but it will stimulate growth in the area of flexion.
Julian
On 1 Sep 2012, at 18:16, Filippo A. Salustri wrote:
> Julian, I appreciate the clarification.
> I wouldn't mind seeing it tried, just to see what would happen, but there's something about this idea - and the generally medieval appearance of the device in the sketches on the OP's website, that give me pause. It just strikes me as too much of humanity trying to force nature to do things - which as far as I know tends to lead only to unexpected (and often undesirable) outcomes.
>
> I'm also reminded of a lovely Maple tree just behind our property, that is growing *through* the metal wire fence at the edge of our property and the ravine behind it.
>
> /fas
>
> On 1 September 2012 12:50, Julian Vincent <[log in to unmask]> wrote:
> I don't know how much of the trunk actually takes part in translocation. Certainly the phloem is peripheral, so squashing the trunk is unlikely to affect the total sectional area of phloem, although it will presumably be constricted. Xylem (transporting water up the stem) might be more compromised - I don't know how much of the xylem is active in a tree trunk. Certainly not all of it, since the heartwood is a repository for spare phenols and general rubbish (or so I am informed). My worry would be that the zone below the clamp wouldn't develop properly since it wasn't subject to normal bending strains. I have a feeling that it would be easier to breed self-pruning fruit.
> On the other hand, nature being what it is, I suspect there are inbuilt responses to such challenges as restriction of the stem.
>
> Julian
>
>
> --
> \V/_
> Filippo A. Salustri, Ph.D., P.Eng.
> Mechanical and Industrial Engineering
> Ryerson University
> 350 Victoria St, Toronto, ON
> M5B 2K3, Canada
> Tel: 416/979-5000 ext 7749
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