Water Potential

Question 1

What is transpiration?

Answer 1

Loss of water vapour via stomata

Transpiration is a crucial process for plants that involves the release of water vapor from the plant’s surfaces, primarily through small openings called stomata.

Question 2

What are the functions of transpiration?

Answer 2

• Cools plant
• Moves nutrients from roots to leaves via xylem

Transpiration helps in temperature regulation and nutrient transport within the plant.

Question 3

How is transpiration controlled?

Answer 3

By guard cells responding to solute potential (K⁺) and turgor pressure

Guard cells regulate the opening and closing of stomata, thus controlling water loss through transpiration.

Question 4

What environmental factor slows down transpiration?

Answer 4

High humidity

When humidity is high, the concentration gradient between the inside of the leaf and the surrounding air decreases, slowing the rate of transpiration.

Question 5

What environmental factor increases the rate of transpiration?

Answer 5

Heat

Higher temperatures increase evaporation rates, leading to increased transpiration.

Question 6

How does wind affect transpiration?

Answer 6

Moves moist air, increases rate

Wind can carry away the moisture around the leaf, maintaining a steep concentration gradient and promoting transpiration.

Question 7

Name a leaf adaptation that helps reduce transpiration.

Answer 7

• Sunken stomata
• Hairs
• Rolled leaves
• Waxy cuticle

These adaptations help minimize water loss by creating a microenvironment that reduces evaporation.