Root pressure
Root pressure is one of the phenomena used by vascular plants to move water into the leaves. The water in the soil tends to be poorer in solutes than the water in the plant's cells, due to the plant's active absorption of dissolved nutrients. The resulting solute potential gradient causes water to flow into the roots. Root pressure is capable, under ideal atmospheric conditions, of pushing water one or two feet above the ground.In some plants, on windless nights, root pressure causes guttation.
