Which of the following are cells of phloem?

The correct answer is Sieve tubes and companion cells.

Key Points

• Sieve tubes are elongated cells in the phloem of flowering plants which are responsible for transporting sugars and other nutrients.
• Companion cells are associated with sieve tube elements and help in the maintenance of the sieve tubes and assist in the transport of photosynthetic products.
• Sieve tubes and companion cells are crucial for the long-distance translocation of organic substances in plants.
• The phloem tissue in plants primarily consists of sieve tubes, companion cells, phloem fibers, and phloem parenchyma.

Additional Information

• Phloem is one of the two types of vascular tissues in plants, the other being xylem.
• Xylem is responsible for the transport of water and minerals from roots to other parts of the plant.
• Sieve plates are the porous end walls that facilitate the flow of materials between sieve tube elements.
• Phloem transport is an active process requiring energy in the form of ATP.
• Source-sink relationship in plants refers to the movement of photosynthates from a source (e.g., leaves) to a sink (e.g., roots, fruits).