In any healthy plant in nature. The Rhizosphere and Mycorizzhial fungi are unquestionably interlinked, they do, in fact prepare the path for the feeder roots as well as maintain a specific pH within the rhizosphere, somewhat independent of the pH of the soil.
If you use a container where this is possible. You can take a sheet of glass or plexiglass and make a window into the root system with a removable light blocking door or panel. Here is an interesting page describing how to make a Rhizosphere Visualization
with an agar suspension and purple bromide dye.
I was giving some deep thought (heavily sativa assisted) the other day while sitting on a bench watching all the nurses walk by, about whether or not, when using full organics with a healthy microherd, if we might be better off with a slightly different target pH then the 6.2-6.8 range so often suggested.
If the mycorizzhial fungi, and the surrounding bacteria and bugziz work more efficienctly at a slightly higher or lower pH. We might be better providing for the plant if we aim for them, as the rhizosphere will be adjusted by the fungi to what the plant needs anyway.
I then drifted off into wondering about layered structured soils with differing degrees of organic waste aimed at providing nutrients through timed decay.
It was damned good herb. Rolanstock...