transpiration and vascular bundles

• where does the majority of transpiration take place

  • the leaves
• describe the process of transpiration

  • water evaporates from the mesophyll spongy tissue layer and diffuses out of the stomota
  • the evaporation creates a shortage of water causing more water to be drawn up from the xylem and leading to a constant transpiration of water which carries mineral ions
• the phyolem

  • dead end that has gap which allows cell sap to diffuse to the leaves to the rest of structures in the plants
  • once diffused it's used for storage or food and there process is caused translocation
• the xy;em

  • made from dead cells which are stengthed with ligen and carries water and mineral ions to roots and rest of the plant
• what controls the rate of tranispiration

  light intensity

  temperature

  air flow
• light intensity of transpiration

  • more photosynthesis
  • more are stomota are open and more water evaporates leading to a higher rate of photosynethesis
• temp

  • warmer it is higher rate of transpiration as particles have more energy and diffuse out of the water quicker
• air flow on transpiration rate

  • water diffuses out of the leaf via diffusion
  • if there is a low amount of air flow that means there are lots of water particles outside of the leaves and have a slower rate of diffusion
  • if there is a large airflow there is a much greater concentration of water inside than outside causing water to diffuse out of the lead quicker
• what is used to measure the rate of transpiration

  • a photometer
• what is assumed when using a photometer

  raise of water is equal to the rate of transpiration

  rate of transpiration = distance of bubble / time taken
• how are pholem cells adapted to their function

  • sieve tube companion cells are laid end to end with perforated end plates to allow the flow of sugars
  • companion cells contain a dense nucleus and mitochondria