Phloem

In vascular plants, phloem is the tissue that carries organic nutrients, particularly sucrose to all parts of the plant where needed. In trees, the phloem is part of the bark, hence the name, derived from the Greek word for "bark".

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Phloem tissue consists of less specialised and nucleate parenchyma cells, sieve-tube cells, and companion cells (in addition albuminous cells, fibers and sclereids). The sieve-tube cells lack a nucleus, have very few vacuoles, but contain other organelles such as ribosomes. The endoplasmic reticulum is concentrated at the lateral walls. Sieve tube members are joined end to end to form a tube that conducts food materials throughout the plant. The end walls of these cells have many small pores and are called sieve plates and have enlarged plasmodesmata.

Plant: Land plants (embryophytes)Non-vascular plants (bryophytes)Hepaticophyta - liverwortsAnthocerotophyta - hornwortsBryophyta - mossesVascular plants (tracheophytes)Lycopodiophyta - clubmossesEquisetophyta - horsetailsPteridophyta - "true" fernsPsilotophyta - whisk fernsOphioglossophyta - adderstonguesS...

Tissue: The word tissue has several meanings:...

Sucrose: Sucrose is the common chemical name for table sugar. Sucrose is a disaccharide; each molecule of sucrose consists of two "simple sugars" (monosaccharides)....