I was looking for those too, didn't see any. The plants look great so I don't think the coloration of the roots is that big of a concern. Just surprised they aren't popping the little hairs yet.Thing I don't see is all the lil fine roots that look like hairs on the larger roots.
You could add a lil h202 and make sure your temps aren't too high. If they go up you can have all kind of lil nasty things start growing.