AP BIOLOGY

Detailed explanation-1: -Phloem is a complex tissue which is concerned with the transport of food materials from leaves to other plant parts. Phloem is composed of sieve tube elements, companion cells, phloem parenchyma and phloem fibres. sieve tubes are longitudinally arranged cells. It is seen associated with the companion cells.

Detailed explanation-2: -Companion cells are large elongated cells of phloem with large nucleus. It is attached to the lateral side of sieve tubes. These cells help in transport of food along with sieve. These are specifically found only in angiosperms.

Detailed explanation-3: -…angiosperms are sieve tubes and companion cells found in the phloem (see angiosperm: Vascular tissue). In other vascular plants, parenchyma cells function in the same way as companion cells (that is, as the sieve cell’s living protoplasm), but they are not derived from the same mother cell as the sieve…

Detailed explanation-4: -Found in the phloem cells of a plant are companion cells. Companion cells are a type of parenchyma cell.

Detailed explanation-5: -Sieve tubes and companion cells are absent in the phloem of pteridophytes.