Little knots on my tomato stem?

Ok folks, I was spraying the Rot Stop on all my tomato, eggplant, pepper and cuke leaves this evening and noticed that one of my tomato plant's stem looks like it has little knots on it? This tomato is planted in a container, so it can't be a nematoid damage, what is it?
joy

Well, I discovered the answer myself and it's okay now that I know what it is; but, in case anyone else is trying topsy turvy's or revolutionary planters expect this, this is normal, it's part of the root system forming along the stem. It is what will make a tomato plant strong and healthy. Since this is on just those two plants, one a topsy and the other a revolutionary planer, I have no worries. Whew.
joy