Graviperceptional changes in the roots of cadmium-treated soybean seedlings.

Plant roots are the main organs through which water, nutrients and pollutants enter the plant body. The roots of soybean plants exhibited absence of root caps and damaged roots when treated with heavy metal cadmium beyond 20 μM. Normally, the roots perceive gravity and grow towards it; but, with heavy metal exposure they become gravi-irresponsive and start growing against the gravity and law of nature. As the graviperception sensors lie in the root cap, roots lose directional growth in the absence of root caps and keep growing in the direction of hilum positioning inside the substratum. So far, no study has reported that heavy metals can cause loss of graviperception in the roots of plants. [ABSTRACT FROM AUTHOR]