Transport in plants

• What do cells on the surface of plant roots grow into ?

  • Hairs which stick out into the soil
• What do the hairs on the root give the plant ?

  • A large surface area - absorbing water and mineral ions from the soil
• Why do root hair cells use active transport ?

  • Concentration of minerals is higher in cells than in soil so the ions are absorbed by active transport
• how is water absorbed in root hair cells ?

  • By osmosis
• What are phloem tubes made of ?

  • Columns of elongated living cells with small pores in the end walls to allow stuff through
• What do phloem tubes transport ?

  • Food substances (mainly sucrose ) made in leaves to the rest of the plant for immediate use or storage
• What is translocation ?

  • Transport of food substances from Leaves to the rest of the plant
• What does translocation require ?

  • Energy from respiration - transport goes both ways
• What are xylem tubes made of ?

  • Dead cells joined end to end with no end walls between them and a hole down the middle .
• What are xylem tubes strengthened by ?

  • Material called lignin
• What do xylem tubes do ?

  • Carry water and mineral ions from the roots To the stem and leaves
• What is the transpiration stream ?

  • Movement of water from roots , through xylem and out of the leaves
• What is transpiration caused by ?

  • Evaporation and diffusion of water from a plants surface
• Where does most transpiration take place ?

  • The leaves
• What does the loss of water in transpiration create ? What happens …

  • Shortage of water in leaf , so more water is drawn up from the rest of the plant through the xylem vessels to replace it .
• What does the transpiration stream carry ?

  • Mineral ions that are dissolved in the water along with it
• What are stomata ? Where are they found

  • Tiny pores on the surface of a plant
  • found on lower surface of leaves
• What does stomata allow CO2 and oxygen to do ?

  • Diffuse directly in and out of a leaf
• What do stomata allow water vapour to do ?

  • Escape during transpiration
• what are guard cells ?

  • cells that change shape to control the size of the pore
• What does a turgid guard cell mean ?

  • Swollen with water
  • the stomata are open
• What do flaccid guard cells mean ?

  • Low on water and limp
  • The stomata are closed
• What is transpiration rate affected by ?

  • Environmental factors
• What environmental factors affect the rate of transpiration ?

  • Light intensity , temperature and air flow