I've notice the interesting phenomenon lately of my radish flowers
turning purple after being white for a while, as the stalk and seed
pods (though not the leaves) take on a purple-red highlight as well.

Just curious, what's happening here? Does the root (the "radish")
release its pigment at some point as it's absorbed? Is it an
indicator of soil pH? Something to do with pollination?

The roots seem to turn from bright red to dark purple around this
point as well.