AP BIOLOGY

Detailed explanation-1: -The photosynthates from the source are usually translocated to the nearest sink through the phloem sieve tube elements. For example, the highest leaves will send sugars upward to the growing shoot tip, whereas lower leaves will direct sugars downward to the roots.

Detailed explanation-2: -Hence, the movement of food through the phloem is bi-directional i.e. both in upward and downward directions. The process of food transportation via the phloem requires ATP. Various elements of the phloem fibers, phloem parenchyma, and companion cells all contribute to the food translocation process.

Detailed explanation-3: -Let us learn a bit more about phloem transport. The transportation occurs in the direction of the source to sink. Transport of organic solutes from one part of the plant to the other through phloem sieve tubes is called translocation of organic solvents.