Xylem and phloem
Plants have tissues to transport water, nutrients and minerals.
- Narrow, hollow, dead tubes with lignin, responsible for the transport of water and minerals in plants. transports water and mineral salts from the roots up to other parts of the plant.
- The tissue in plants that transports the products of photosynthesis, including sugars and amino acids. transports sucrose and The building blocks that make up a protein molecule. from the leaves and other parts of the plant.
This table explains what is transported by the xylem and phloem.
| Tissue | Transported | Process |
| Xylem | Water and minerals | Transpiration stream |
| Phloem | Sucrose and amino acids | Translocation |
| Tissue | Xylem |
|---|---|
| Transported | Water and minerals |
| Process | Transpiration stream |
| Tissue | Phloem |
|---|---|
| Transported | Sucrose and amino acids |
| Process | Translocation |
Xylem
Mature xylem consists of elongated dead cells, arranged end to end to form continuous vessels (tubes).
Mature xylem vessels:
- contain no The living substance inside a cell (not including the nucleus).
- are A substance which fluids are unable to pass through. to water
- have tough walls containing a woody material called lignin
Phloem
Phloem consists of living cells arranged end to end. Unlike xylem, phloem vessels contain cytoplasm, and this goes through the holes in the sieve plates from one cell to the next.
Phloem transports sucrose and amino acids up and down the plant. This is called The transport of dissolved material within a plant.. In general, this happens between where these substances are made (the sources) and where they are used or stored (the sinks).
This means, for example, that sucrose is transported:
- from sources in the root to sinks in the leaves in spring time
- from sources in the leaves to sinks in the root in the summer
Applied chemicals, such as A chemical used to kill pests, such as the potato cyst nematode which is a pest that destroys potato crops., also move through the plant by translocation.