Assertion : Translocation of sugar from source (leaf) to sink is defined as pressure flow hypothesis. Reason: Translocation of the solute is facilitated through living phloem sieve tube cells.

Step-by-step solution

The accepted mechanism for the translocation of sugars from source to sink is called pressure flow hypothesis. The glucose is prepared at the source by photosynthesis, it is converted to sucrose (a disaccharide). The sugar is then moved in the form of sucrose into the companion cells and then into living phloem, sieve tube cells by active transport.