The xylem is a tissue which transports water and minerals from the roots up the plant stem and into the leaves.
Xylem consists of dead cells. The cells that make up the xylem are adapted to their function:
Transport in the xylem is a physical process. It does not require energy.
The phloem moves food substances that the plant has produced by photosynthesis to where they are needed for processes such as:
Transport in the phloem is therefore both up and down the stem. Sucrose is the transport sugar in the phloem. Transport of substances in the phloem is called translocation. Translocation requires energy as it is an active process.
Phloem consists of living cells. The cells that make up the phloem are adapted to their function:
|Type of transport||Physical process||Requires energy|
|Substances transported||Water and minerals||Products of photosynthesis; includes sucrose and amino acids dissolved in water|
|Direction of transport||Upwards from roots to leaves||Upwards and downwards|