phloem tissue transports solutes, mainly sugars like sucrose, round plants.
like xylem phloem is formed from cells arranged in tubes.
unlike xylem, its purely a transport tissue - isn't used for support as well
phloem tissue contains phloem fibers, phloem parenchyma, sieve tube elements and companion cells.
sieve tube elements are living cells that form the tube for transporting sugars through the plant. They are joined end to end to form sieve tubes. the sieve parts have lots of holes to allow for solutes to pass through
what do sieve tube elements not have compared to normal living cells
no nucleus, very thin layer of cytoplasm, and few organelles
sieve tube elements
A) cytoplasm
B) sugars
C) companion
companion cells -the lack of nucleus and other organelles in sieve tube elements means they cant survive on their own so there is a companion cell for every sieve tube element
carry out living functions for both themselves and their sieve cell e.g. provide energy for active transport of solutes
