Summary
Xylem and phloem are specialized plant tissues responsible for transporting substances throughout the plant. Xylem transports water and mineral ions from the roots to other parts of the plant, while phloem transports nutrients like sucrose and hormones in both directions.
- Xylem — vessel that carries water and minerals. Example: Xylem vessels are made of hollow, dead cells joined end-to-end, thickened with lignin for support.
- Phloem — vessel that carries food and plant hormones. Example: Phloem vessels are made of living cells and transport substances through translocation, an active process.
- Transpiration Pull — passive process used by xylem to transport water. Example: Water moves upwards from roots to leaves without energy.
- Translocation — active process used by phloem to transport nutrients. Example: Sucrose is moved from leaves to roots using energy.
Exam Tips
Key Definitions to Remember
- Xylem: vessel that carries water and minerals
- Phloem: vessel that carries food and hormones
- Transpiration Pull: passive water transport in xylem
- Translocation: active nutrient transport in phloem
Common Confusions
- Confusing the direction of transport in xylem and phloem
- Thinking xylem uses energy for transport
Typical Exam Questions
- What is the function of xylem? Transports water and mineral ions from roots to leaves.
- What is translocation? Movement of sucrose and nutrients in phloem using energy.
- Which tissue is stained red in a dye experiment? Xylem, as it transports water.
What Examiners Usually Test
- Differences between xylem and phloem
- Structure and function adaptations of xylem and phloem
- Direction and energy use in transport processes