# Follow up to the recent Asymmetry podcast on Soil Science with Ian Hunter **URL:** \ **Category:** Horticulture\ **Created:** [March 3, 2019, 1:59am UTC](https://forum.bonsaimirai.com/t/follow-up-to-the-recent-asymmetry-podcast-on-soil-science-with-ian-hunter/2703 "2019-03-03T01:59:06Z")\ **Posts on this page:** 1\ **Showing post:** 24
**Author:** ![darren](https://avatars.discourse-cdn.com/v4/letter/d/e9a140/32.png) [@darren](https://forum.bonsaimirai.com/u/darren)\ **Post date:** [March 26, 2019, 2:59pm UTC](https://forum.bonsaimirai.com/t/follow-up-to-the-recent-asymmetry-podcast-on-soil-science-with-ian-hunter/2703/24 "2019-03-26T14:59:18Z")
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/](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 🙂 --- _[View the full topic](https://forum.bonsaimirai.com/t/follow-up-to-the-recent-asymmetry-podcast-on-soil-science-with-ian-hunter/2703)._