Root depth studies with desert holly Atriplex hymenelytra
Atriplex hymenelytra (Torr.) Wats. (desert holly), a highly drought-resistant desert plant, was used as a test plant to study root behavior in wet and dry soils. Roots did not penetrate dry soil, but continued to grow profusely in soil having adequate soil moisture. Roots extracted water from soil progressively downward. They dried soil to −60 bars even though more water was available at a greater depth.