 The mixture was absorbed readily through the protrusions in the rough-walled chamber, but even after sitting on the smooth-walled chamber surface for 20 hours, no absorption was observed.The protrusions that make the walls rough are inward facing modified root structures that make nutritional uptake through the plant’s rough-walled chambers possible.The cavities are also a measure of fitness—a plant with more cavity area means that it has a lighter tuber.