Roots of Pisum sativum L. Exhibit Hydrotropism in Response to a Water Potential Gradient in Vermiculite

Hydrotropism of pea roots in vermiculite

The significance of hydrotropism in influencing the direction of root elongation in soil or similar media has been unclear hitherto. Tsuda et al. (pp. 767-770) demonstrate positive root hydrotropism can occur when a steep and stable gradient in water potential is applied across roots of the agravitropic mutant of pea growing in vermiculite. This finding demonstrates that hydrotropism is not restricted to air-grown roots.