AP BIOLOGY

Detailed explanation-1: -(i) Water and minerals, and food are generally moved by a mass or bulk flow system. (ii) Bulk flow can be achieved either through a positive hydrostatic pressure gradient or a negative hydrostatic pressure gradient. (iii) The bulk movement of substances through the conducting tissues of plants is called translocation.

Detailed explanation-2: -Mass flow, also known as mass transfer and bulk flow, is the movement of fluids down a pressure or temperature gradient, particularly in the life sciences. As such, mass flow is a subject of study in both fluid dynamics and biology.

Detailed explanation-3: -Mass flow or bulk flow is the movement down a pressure gradient ( a pressure gradient in plants is observed due to variations in solute concentration) or temperature gradient of substances in bulk or in masses. Xylem and phloem in plants play a similar role as veins and arteries in animals.

Detailed explanation-4: -The Mass Flow Hypothesis It states that mass flow of solutes takes place in the phloem in the following stages: Sucrose moves from companion cells into sieve tube elements by active transport. This reduces the water potential of the sieve tube element.