NEET BIOLOGY

Detailed explanation-1: -Companion cells – transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy.

Detailed explanation-2: -Phloem is comprised of cells called sieve-tube elements. Phloem sap travels through perforations called sieve tube plates. Neighboring companion cells carry out metabolic functions for the sieve-tube elements and provide them with energy.

Detailed explanation-3: -Phloem parenchyma cells, called transfer cells and border parenchyma cells, are located near the finest branches and terminations of sieve tubes in leaf veinlets, where they also function in the transport of foods.

Detailed explanation-4: -Phloem is a complex permanent plant tissue that helps in the transportation of food. It is made up of sieve tubes, companion cells and phloem parenchyma. It transports food bidirectionally.