Transpiration and translocation

• What is the main function of phloem tubes in plants?

  To transport food substances, mainly dissolved sugars, from the leaves to the rest of the plant.
• What are phloem tubes made of?

  Columns of elongated living cells with small pores in the end walls.
• How do phloem tubes transport food substances?

  They transport food substances made in the leaves to the rest of the plant for immediate use or storage.
• In which directions do phloem tubes transport substances?

  In both directions.
• What is the process called by which phloem tubes transport food?

  Translocation.
• What do xylem tubes primarily transport?

  Water and mineral ions from the roots to the stem and leaves.
• What is the structure of xylem tubes?

  Made of dead cells joined end to end with end walls between them and a hole down the middle, strengthened with lignin.
• What is the movement of water from the roots through the xylem called?

  Transpiration stream.
• What causes transpiration in plants?

  The evaporation and diffusion of water from a plant's surface, primarily at the leaves.
• What happens to the water level in the leaves during transpiration?

  A slight shortage of water is created, drawing more water up from the rest of the plant.
• How does transpiration affect water movement in the plant?

  It creates a constant transpiration stream of water drawn up from the roots.
• Why is transpiration considered a side-effect of leaf structure?

  Because leaves are adapted for photosynthesis, requiring stomata for gas exchange.
• How do stomata contribute to transpiration?

  They allow water to escape from the leaves by diffusion.
• What is the direction of water transport in xylem tubes?

  Only upwards.
• What are the key differences between phloem and xylem tubes?

  • Phloem transports food substances in both directions.
  • Xylem transports water and minerals only upwards.
  • Phloem is made of living cells; xylem is made of dead cells.
• What is the overall process of transpiration in plants?

  1. Water evaporates from the leaves.
  2. This creates a shortage of water in the leaves.
  3. More water is drawn up from the rest of the plant through xylem vessels.
  4. A constant transpiration stream is established from roots to leaves.
• How are leaves adapted for photosynthesis and transpiration?

  • Leaves have stomata for gas exchange.
  • They have a large surface area for light absorption.
  • The internal structure allows for efficient water loss and nutrient uptake.