What is the role of companion cells?

Answer: Angiosperms’ phloem contains a living cell known as a partner cell (flowering plants).

Every companion cell has a sieve element cell as a close friend. It controls how a sieve cell behaves. Sieve cells are reliant on their nearby companion cells because they lack a nucleus. Sieve components and progenitor cells have a close relationship. Phloem is where these cells are located in flowering plants. They move amino acids and sugar from and to the sieve components. The transmembrane proteins are used by the partner cells in the leaf (the tissue of origin) for the rapid transit of amino acid residues and sugar.

The transportation of carbohydrates in the phloem begins at the source, where they are put into a sieve tube. Loading creates a slope in the water content, which facilitates the flow of the sugar.