You could also cut a stem off the plant and place the stem in a glass of water. The cut stem will return to normal much faster than the potted plant because it does not have to pull water through the roots. As the soil dries, root growth slows. The zone of elongation becomes shorter and the casparian strip reaches almost to the root tip. This reduces both water loss and water uptake by the root.
Many plants have root hairs on their roots.
These are tiny rootlets increase the root's surface area, which increases the absorption of water and nutrients. Blueberries are unusual in that they do not have root hairs. Therefore the root surface of a blueberry root system is smaller than in other plants. In most root systems, most of the roots are located in the uppermost soil layer. This is also true in blueberries.