Factors Influencing Plant Transpiration Rate

Steps:

• Transpiration is the evaporation of water from plant leaves through stomata, driven by environmental factors.
• Key drivers include light (stomatal opening), temperature (evaporation speed), wind (air movement), and humidity (vapor gradient).
• Increased humidity reduces the concentration gradient of water vapor between leaf and air, slowing diffusion.
• Other factors enhance the gradient or stomatal activity, boosting transpiration.

Why A is correct:

• Increased humidity decreases the water vapor concentration gradient from leaf to air, reducing transpiration rate per Fick's law of diffusion.

Why the others are wrong:

• B: Increased sunlight triggers stomatal opening, increasing water loss pathways.
• C: Increased temperature accelerates kinetic energy of water molecules, speeding evaporation.
• D: Increased wind speed disperses the boundary layer of humid air, maintaining a steep diffusion gradient.

Final answer: A