transport systems in plants

• xylem transport water and dissolved minerals up the stem and have no living cells

  lignin rings makes them strong to withstand water pressure
• phloem transport sugar up and down

  made from living cells - companion cells control sieve cells
• the leaf

  upper epidermis prevents water loss

  palaside mesophyll contain chloroplasts with chlorophyll for photosynthesis

  spongy mesophyll are loosely packed for gas exchange

  guard cells control size of stomata

  lower epidermis regulates water loss and gas exchange

  stoma allows gas diffusion and water to exit
• transpiration is the continuous passage of water from the roots to the leaves
• water is - absorbed by the roots , transported up xylem , evaporates leaf's through stomata
• soil to root hair cells ( large surface area ) due to osmosis
• transpiration is increased by increasing wind , temperature , surface area and decreasing humidity