Diffusion and active transport are the two types of lateral pathways that is responsible for the movement of sucrose from source cell into the sieve tube. Sugar molecules are moved into the sieve elements which are the phloem cells through active transport i.e. with the use of energy. The water produces turgor pressure in the sieve elements, which pushes the sugars and fluids down the phloem tubes toward the storage sites. it also moved through simple diffusion due to difference in concentration i.e. from higher to lower concentration region.
