Transpiration

Question 1

Name 2 physiological mechanisms involved in transpiration

Answer 1

1. Stomatal regulation
2. Transpiration-Cohesion-Tension mechanism

Question 2

Describe transpiration

Answer 2

The process by which water is lost from plants through stomata as vapour. Driving the movement of water from the roots to leaves through the xylem in the vascular system - this creates a transpiration pull.

Question 3

How does water enter a vine

Answer 3

Through osmosis, The water potential inside the cell is lower than outside so the water moves down the water potential gradient. ( through a partially permeable membrane)

Question 4

Describe stomatal regulation

Answer 4

Stomata are gas valves - they open when guard cells take up water- Photsynthesis needs gaseous exchange and so stomata must be open, This can mean water loss if excessive through transpiration and so stomata can close when a vine is water stressed.

Question 5

Environmental Factors that affect transpiration

Answer 5

Humidity - transpiration decreases as humidity increases as it reduces the rate of evaporation from the leaf
Temperature - Leaf temp increases transpiration as evaporation increases
Wind - increases transpiration by increasing rate of evaporation of water from surface.

Question 6

Cultural factors that effect transpiration

Answer 6

Canopy management - effects how many leaves
irrigation

Question 7

Describe the transpiartion Cohesion-Tension mechanism

Answer 7

Xylem sap rises against gravity with the help of capillary action - stomata open to let water escape and co2 enter