practicals

• What is the first step in the method described?

  Cut a shoot underwater
• Why is the shoot cut underwater?

  To prevent air from entering the xylem
• What should be done after cutting the shoot?

  Place the shoot in the tube
• What is important about the apparatus setup?

  It must be airtight, sealed with vaseline
• What happens if air enters the apparatus?

  The readings will be affected
• What should be done to the leaves of the shoot?

  Dry the leaves of the shoot
• Why is it necessary to dry the leaves?

  Moisture affects the rate of transpiration
• What should you do after drying the leaves?

  Remove the capillary tube to form an air bubble
• What should be set up after forming the air bubble?

  Set up the environmental factor being investigated
• How long should the plant adapt to the new environment?

  For 5 minutes
• What should be recorded after the adaptation period?

  Record the starting location of the air bubble
• What should be done after recording the starting location?

  Leave for a set period of time
• What should be recorded after the set period of time?

  Record the end location of the air bubble
• What should be changed during the experiment?

  Change one environmental factor being investigated
• What should be done to reset the bubble?

  Open the tap below the reservoir
• What does the distance the bubble travels indicate?

  The rate of transpiration occurring
• What does a further bubble travel indicate?

  Faster transpiration is occurring
• What does a shorter bubble travel indicate?

  Slower transpiration is occurring
• What environmental factor can be investigated using a fan or hairdryer?

  Airflow
• How can humidity be tested in a plant experiment?

  By spraying water in a plastic bag
• What method can be used to change light intensity for a plant?

  Change the distance of a light source
• What are the two temperature conditions mentioned for plant experiments?

  Cold room or warm room
• What are the methods to investigate environmental factors affecting plants?

  • Airflow: Use a fan or hairdryer
  • Humidity: Spray water in a plastic bag
  • Light intensity: Change distance of light source
  • Temperature: Use cold or warm room
• What is the effect of high temperature on transpiration in plants?

  It results in more transpiration
• How does increased temperature affect the kinetic energy of water molecules?

  It increases the kinetic energy of water molecules
• What happens to transpiration as temperature increases?

  Transpiration occurs faster
• What is the source of water molecules that evaporate during transpiration?

  From the mesophyll
• What is the process that occurs when water molecules evaporate and diffuse away?

  Transpiration
• What are the steps in the method for measuring transpiration using a capillary tube?

  1. Record distance of air bubble at start.
  2. Use a stopwatch for a set time (e.g., 15 mins).
  3. Record end location of air bubble and calculate distance travelled.
  4. Reset air bubbles using tap of reservoir if necessary.
  5. Repeat with different factors being investigated.
• What is the initial action taken in the transpiration measurement method?

  Record distance of air bubble at start
• Why is a stopwatch used in the transpiration measurement method?

  To measure a set period of time
• What should be done after recording the end location of the air bubble?

  Calculate the distance travelled
• What should be done if the air bubbles need resetting during the experiment?

  Use tap of reservoir to reset
• What can be changed in the transpiration measurement experiment?

  The factor being investigated