Observations on the combined effect of ultrasound and certain cytoxics on the growth of the roots of Zea mays.

Seedling roots of Zea mays were used in combined treatments with ultrasonic radiation (pulsed and continuous beams) and the cytotoxic drugs vincristine and hydroxyurea respectively. It has been found that ultrasound and the above-mentioned drugs act independently of each other, a result similar to that obtained with ultrasound and X rays. This leads to the suggestion that the mechanism of damage due to the drugs is different from that due to ultrasound. An increase in drug effectiveness under the action of ultrasound has not been found.