phloem tissue

function of phloem tissue

to transport sucrose and amino acids

what are the 4 different types of cells it is made up from

• sieve tubes

• companion cells

• phloem fibres

• phloem parenchyma

function of the sieve tubes

transport sucrose and amino acid up and down the plant stem

• transport photosynthates (sucrose and amino acids)

• sieves tubes formed from sieve elements placed end to end

• cellulose walls at the end of these cells are perforated to form sieve plates

• sieve plates allow cytoplasm from one cell to run into adjacent cell

fucntion of companion cell

connect sieve tubes via plasmodesmata

• companion cells do not transport organic matter but provide ATP for active transport of sugars in/out of sieve tubes

• has a nucleus

function of phloem fibres

provide support

3 ways in which sieve tube elements are adapted for their function

• have companion cells, provide ATP for active transport of sugars in/out of sieve tubes

• fewer organelles, this means more space for transport of solutes

• ends of walls are perforated, allowing passage of dissolved solutes (sucrose, amino acids)