Plant Organ System

• What is translocation in plants?

  The movement of food substances through the phloem
• What is transpiration in plants?

  The loss of water vapour from leaves and stems
• How does temperature affect the rate of transpiration?

  Higher temperatures increase the rate of transpiration
• How does relative humidity affect transpiration?

  High humidity decreases the rate of transpiration
• How does air movement affect transpiration?

  Increased air movement increases the rate of transpiration
• How does light intensity affect transpiration?

  Higher light intensity increases the rate of transpiration
• What is a potometer used for?

  To measure the uptake of water by a plant
• What is the function of guard cells in plants?

  They control the opening and closing of stomata
• How do guard cells respond to water availability?

  They fill with water to open stomata when water is available
• What forms the plant organ system for transport?

  • Roots
  • Stem
  • Leaves
  • Involves root hair cells, xylem, and phloem
• What is translocation in plants?

  The movement of food substances made in the leaves up or down the phloem
• What is transpiration in plants?

  The loss of water vapor from the leaves and stems of the plant
• How does transpiration occur in plants?

  • Water evaporates at open stomata
  • Water molecules are attracted to each other
  • When some leave, others are pulled up through the xylem
  • Results in continuous transpiration stream
• What factors affect the rate of transpiration?

  • Increase in temperature: Faster evaporation
  • Increase in relative humidity: Slower transpiration
  • Increased air movement: Faster transpiration
  • Increase in light intensity: More stomata open, increasing transpiration
• How does an increase in temperature affect transpiration?

  It increases the rate of transpiration due to faster evaporation
• What happens to transpiration when relative humidity increases?

  The rate of transpiration decreases due to a reduced concentration gradient
• How does increased air movement affect transpiration?

  It increases the rate of transpiration by creating a steeper concentration gradient
• What effect does increased light intensity have on transpiration?

  It increases the rate of transpiration by opening more stomata
• How is the rate of transpiration measured?

  • By measuring the uptake of water by the plant
  • Observed using a potometer
  • Measures the distance traveled by a bubble in a tube of water
• What are the features of guard cells in plants?

  • Kidney-shaped
  • Thin outer walls and thick inner walls
  • Open stomata when filled with water
  • More stomata on the bottom of the leaf to minimize water loss