Transpiration

• What does transpiration involve?

  Release of water vapour from plant leaves
• What is xylem tissue composed of?

  Hollow tubes strengthened by lignin
• In which direction does water move in the xylem?

  From the roots to the leaves
• What is the transpiration stream?

  The movement of water from roots to leaves
• What is phloem tissue composed of?

  Elongated cells that transport sugars
• What is translocation in plants?

  Movement of sugars in phloem
• How do dissolved sugars travel in phloem?

  Through pores in the end walls
• What is the role of root hair cells?

  To actively transport mineral ions from soil
• How does water enter the root hair cells?

  By osmosis due to water potential gradient
• What is root pressure?

  Pressure that pushes water up from roots
• What is cohesion tension theory?

  Water is pulled up by transpiration pull
• What causes negative pressure in the xylem?

  Evaporation of water from leaves
• What is adhesion in relation to water movement?

  Water molecules attract to container walls
• How does temperature affect transpiration rate?

  Higher temperature increases transpiration rate
• How does wind speed affect transpiration?

  Increased wind speed raises transpiration rate
• How does humidity affect transpiration?

  Lower humidity increases transpiration rate
• How does light intensity affect transpiration?

  Higher light intensity increases transpiration rate
• How is transpiration measured?

  Using a potometer with a cut plant stem
• What happens to the air bubble in a potometer?

  It shows how much water the stem takes up
• What happens if air enters the xylem?

  Transpiration stops
• What is the main driving force of transpiration?

  Cohesion tension
• What is the role of hydrogen bonds in water molecules?

  They create cohesion between water molecules
• How does transpiration affect tree trunk diameter throughout the day?

  Trunk diameter is wider at night
• What is the tallest species of tree?

  Redwoods
• What happens to transpiration during the daytime?

  Transpiration occurs more due to evaporation
• What is the significance of root pressure in young plants?

  It helps transport water before leaves develop
• What is the relationship between transpiration and photosynthesis?

  Transpiration opens stomata for gas exchange
• How do cohesion and adhesion contribute to water movement?

  Cohesion pulls water up, adhesion helps it stick
• What is the effect of increased kinetic energy on transpiration?

  It increases the rate of transpiration
• What is the process of evaporation?

  Liquid turning into gas
• What is the role of stomata in transpiration?

  They allow water vapour to exit the plant
• How does transpiration affect water potential in the plant?

  It creates a gradient for water movement
• What happens to the concentration gradient during transpiration?

  It maintains a steep gradient for diffusion
• What is the main component of xylem walls?

  Lignin
• What is the significance of the holes in phloem cells?

  They allow cell sap to move between cells
• How does transpiration affect the overall health of a plant?

  It regulates water and nutrient transport
• What is the relationship between transpiration and root pressure?

  Root pressure pushes water up, transpiration pulls it
• What is the role of mineral ions in root pressure?

  They lower water potential in root tissue
• How does transpiration affect the water potential gradient?

  It creates a continuous gradient for water movement
• What happens to the water potential of the soil compared to the cell sap?

  The soil's water potential is less negative