No, no, no, no.

Relaxation of lending standards and margin requirements make bubbles. Low interest rates have nothing to do with it. You get bubbles at 7 % rates. You get bubbles at 3 % rates. You get bubbles at 0 % rates. Hell, the broker's rate touched 12 % for a while during the spring of 1929. When you have that sort of short-term returns to speculative activity, fiddling with the rediscount rate barely amounts to a rounding error.