There are concentration gradients in such areas that affect particles motion strongly.
Diffusion is the movement of molecules due to a concentration gradient.
A concentration gradient is established between the root and the soil water.
According to the theory, sometimes water is absorbed against concentration gradient.
These are absorbed by the root hairs against a concentration gradient.
They have a rich blood supply to keep a concentration gradient.
This concentration gradient is created by molecules which cannot pass through the membrane.
These forms of transport require energy, as the products being transported are usually moving against a higher concentration gradient.
Building a concentration gradient of non-volatile components at the surface is another.
Due to a concentration gradient of the ions, mass transport must take place.