transpiration & translocation

• what are phloem tubes made out of?

  enlogated living cells - small pores to allow cell sap to flow through
• what do phloem tubes do?


  transport food substances made in the leaves ro the rest of the plant for immediate use or for storage
• what way does the transport go in phloem tubes?

  both directions
• what is translocation?


  the movement of food molecules through the phloem tissue
• what are xylem tubes made up of?

  dead cells joined end to end - no end walls - they are strengthened with a material called lignin
• what is the xylems job?

  to carry water and mineral ions from the roots to the stem and leaves
• what is the transportation stream?

  the movement of water from the roots through the xylem and out of the leaves
• where in a plant is water most commonly lot to the environment?

  at the leaves
• which strengthening material is present in xylem tubes?

  lignin
• what Is the main type of food molecule transported around the plant in phloem tubes?

  dissolved sugars
• describe the movement of food molecules via phloem tubes.


  food molecules move through phloems in both directions - the food molecules move from the leaves (where they are made) to the rest of the plant.
• how does the structure of the phloem allow cell sap to move between phloem cells?

  there are pores in the end walls of phloem tubes for the cell sap to move through
• explain the constant transpiration stream of water through a plant


  evaporation & diffusion creates a shortage of water in the leaf. this means more water is drawn up from the rest of the plant though the xylem vessels to replace it - this causes more water to be drawn up from the roots