Transpiration (Factors Affecting and Stomatal Mechanism)
Covers the process of transpiration, factors influencing its rate, and the mechanism of stomatal opening and closing.
What is Transpiration (Factors Affecting and Stomatal Mechanism)?
The process where plants absorb water through the roots and then give off water vapor through pores in their leaves.
Key points
- Define transpiration and its significance.
- Identify and explain the effect of various external factors on the rate of transpiration.
- Describe the mechanism of stomatal opening and closing.
- Understand the role of guard cells and ion movement in stomatal regulation.
Common exam trap
Confusing transpiration with guttation.
Definitions
- Term
Transpiration
- Meaning
The process where plants absorb water through the roots and then give off water vapor through pores in their leaves.
- Term
Stomata
- Meaning
Pores, usually on the leaf surface, that allow for gas exchange (CO2 in, O2 and H2O out).
- Term
Guard Cells
- Meaning
Paired cells that surround and control the opening and closing of a stoma.
- Term
Turgor Pressure
- Meaning
The pressure exerted by the fluid inside a plant cell against the cell wall.
Learning objectives
Define transpiration and its significance.
Identify and explain the effect of various external factors on the rate of transpiration.
Describe the mechanism of stomatal opening and closing.
Understand the role of guard cells and ion movement in stomatal regulation.
Prerequisites
Plant Anatomy (stomata, guard cells)
Water Potential
Osmosis
Diffusion
Common mistakes
Confusing transpiration with guttation.
Underestimating the role of wind in transpiration (can both increase and decrease the rate).
Not understanding the active transport of ions in guard cell function.
Forgetting that stomata are not the only sites of transpiration (lenticels, cuticle).
Keywords
Transpiration
Stomata
Guard Cells
Water Potential
Turgor Pressure
Abscisic Acid
Environmental Factors
Plant Physiology
Practice preview
Which of the following factors does NOT affect the rate of transpiration?…
easy
Which of the following conditions would lead to the closure of stomata?…
easy
A plant is subjected to conditions of high temperature, low humidity, and moderate wind. Simultaneously, its roots are placed in a solution with a very low water potential (e.g., a concentrated salt solution). Predict th…
hard