Plants like Microwaved water (once it cools down)

This one is straight from Mythbusters on TV. My wife said she watched this. The experiment was to test to see which water plants did the best in: regular water, boiled water after it cooled down or microwaved water once it cooled down.

It turns out that actually plants did the best with microwaved water once it had cooled down.

I was talking to my wife about this and here is why I thought this was true. I said, "Well. Likely microwaving water kills bacteria."

Here response was: "Well. Boiling water would kill bacteria too."

I didn't have a response or a useful explanation for this. Maybe you can figure this out.