transpiration and translocation

• Which part of the plant is glucose produced in

  • leaves
• What do we call the movement of cell sap (a mixture of sugar and water) up and down the plant?

  • translocation
• Phloem cells have pores in their end walls to allow cell sap to pass along the phloem tube. 
• xylem transports Water and dissolved mineral ions in a plant
• root hair cells absorb mineral ions from the soil by active transport
• Xylem cells are reinforced with lignin, which makes them stronger and helps support the plant
• transpiration:

  • The evaporation of water from the leaves
• Why does the rate of transpiration increase if the light intensity is increased:

  • The stomata open wider to let more carbon dioxide into the leaf for photosynthesis.
• Why does water loss slow down if a plant is put into a plastic bag

  • more humidity
• The movement of sugars throughout a plant is called translocation
• factors that effect rate of transpiration:

  • temperature
  • humidity
  • wind speed
  • light intensity
• light intensity :

  • increased light intensity causes stomata to open wider for photosynthesis, leading to higher transpiration rates
• temperature:

  • higher temperatures increase evaporation from leaf surfaces, speeding up transpiration.
• humidity:

  • Lower humidity levels increase the rate of transpiration because the air around the leaf is drier, creating a steeper concentration gradient.
• wind speed:

  • More wind removes the water vapor surrounding the leaf, maintaining a high diffusion gradient and increasing transpiration.