BOTANY

Detailed explanation-1: -Sugars produced in sources, such as leaves, need to be delivered to growing parts of the plant via the phloem in a process called translocation, or movement of sugar. The points of sugar delivery, such as roots, young shoots, and developing seeds, are called sinks.

Detailed explanation-2: -The mechanism by which sugars are transported through the phloem, from sources to sinks, is called pressure flow. At the sources (usually the leaves), sugar molecules are moved into the sieve elements (phloem cells) through active transport.

Detailed explanation-3: -Phloem is composed of living cells that transport a water solution of sugars that we commonly call sap. This movement is modeled by the pressure-flow theory, a part of which is that the sugar-containing fluid is moved through sieve tubes by fluid pressure.

Detailed explanation-4: -SWEETs transport diverse substrates including glucose and sucrose which is involved in long-distance sugar transport through a phloem loading mechanism from the source (leaves) to sink (fruits, roots) tissue.

Detailed explanation-5: -Phloem loading via the apoplast or by polymer trapping elevates the concentration of sugar in the companion cells to much higher levels than in the mesophyll and is therefore thermodynamically active.