The Plant Vascular System

Front 1

What does the vascular system transport?

Back 1

Transports water, minerals and sugars (does not use diffusion alone.

Front 2

Xylem

Back 2

Hollow narrow tube that transports water and minerals from the roots to the leaves of the plant.

• Xylem made of vessel called xylem vessel elements, stacked end to end

• Xylem cells are dead, with no cytoplasm or organelles and no end plates between the cells

• Walls of the xylem contain lignin which adds strength to the xylem and keeps water inside

• Water can pass to nearby xylem through pits in the xylem

Hint 2

Front 3

Phloem

Back 3

Transports sugars(usually sucrose) and other assimilates up and down the plant.

• Made of cells called sieve tube elements, stacked end to end to make a narrow tube, with a sieve plate between them

• Sieve plates contain many pores that allow sugars through

• Phloem cells are living, but contain a thin layer of cytoplasm around the edge of the cell and few organelles

• Each phloem cell is supported by a companion cell that loads sugars (mostly sucrose) into the phloem. Companion and phloem cells are linked by pores in the phloem wall called plasmodesmata

Hint 3

Front 4

The role of companion cells in the phloem tissue

Back 4

• To provide support for the phloem sieve tube elements

• Lacks organelles, the companion cell with its nucleus, mitochondria, ribosomes, enzymes etc controls the movement of solutes and provides ATP for active transport in the sieve tube element