AP BIOLOGY

Detailed explanation-1: -phloem, plant vascular tissue that conducts foods made in the leaves during photosynthesis to all other parts of the plant. Phloem is composed of various specialized cells called sieve elements, phloem fibres, and phloem parenchyma cells.

Detailed explanation-2: -The structural elements of phloem include sieve tubes, companion cells, phloem parenchyma and secretory cells. The sieve tube is the conducting element of the phloem. It is formed from a vertical series of elongated cells, interconnected by perforations in their walls in areas known as sieve plates.

Detailed explanation-3: -Phloem tissue consists of conducting cells, generally called sieve elements, parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells and supportive cells, such as fibres and sclereids.

Detailed explanation-4: -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.

Detailed explanation-5: -Companion cells – transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy. A sieve tube is completely dependent on its companion cell(s).