Examples of mass flow include blood circulation and transport of water in vascular plant tissues.
In general, bulk flow in plant biology typically refers to the movement of water from the soil up through the plant to the leaf tissue through xylem, but can also be applied to the transport of larger solutes (e.g. sucrose) through the phloem.
[2] As in blood circulation in animals, (gas) embolisms may form within one or more xylem vessels of a plant.
If an air bubble forms, the upward flow of xylem water will stop because the pressure difference in the vessel cannot be transmitted.
[4] That is, as solutes are off-loaded into sink cells (by active or passive transport), the density of the phloem liquid decreases locally, creating a pressure gradient.