Follow up to the recent Asymmetry podcast on Soil Science with Ian Hunter

Horticulture
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Give me a rough address for dealers nearby. Emailing him back with my address as well.

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One thing that will be interesting to see, is whether cultivating/inoculating micro-organisms that produce cytokinins in order to promote ramification will have the undesired effect of reducing lateral root formation, and if it does, whether that is a problem…

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Hmm, I was under the assumption that promoting ramification in the branching would also promote ramification and bifurcation in the roots (lateral or otherwise), but this assumption wasn’t based on anything other than the fact that Ryan talks so much about the ramification in the the roots mirroring the ramification in the branching. Is there an underlying horticultural reason cytokinins would suppress lateral root growth?

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Yeah so a while ago after the Telperion farms podcast I did a little reading around cytokinin and auxin.

The summary is:

  • Auxin promotes apical dominance in the branches by suppressing lateral bud formation / development
  • Auxin promotes lateral root formation
  • Cytokinin promotes lateral growth in the branches
  • Cytokinin promotes apical dominance in the roots by suppressing lateral root formation / development
  • The balance of the two hormones (among other factors I’m sure) determines the outcome - apical dominance vs side shoot growth above and below the soil surface
  • Interestingly ethylene - the substance given off by bananas that ripens other fruit - also helps stimulate lateral root formation (though apparently too much suppresses growth!)

When you think deeply about that relationship, a lot of things in bonsai start to make even more sense - and can’t help but wonder at what a simple but beautiful system it is!

Reference https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2803412/

Obviously we are hypothesising about the outcome of a hypothesis, but I found it interesting and would be keen to see what happens when Mirai start testing :slight_smile:

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Thanks so much for sharing your research and this source! It seems like auxin and cytokinin mirror each other with opposite results, like cytokinin is the “auxin of the roots” and vice versa.

I wonder if this means that you can only manipulate these hormones to benefit the refinement of the branches or the roots, to the detriment of the refinement of the other. If that is the case, which should you work on developing first? Or, can you stimulate cytokinin in the branches and auxin in the roots to have the best of both worlds?

I guess I’ll spend my day at work doing research that has nothing to do with my actual job :shushing_face:

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Ryan talks about his preference for akadama because it causes root branching and finer roots. I believe he also states that ramification of roots leads to branch ramification.
Has anyone come across any information as to how or why one causes the other?