Transpiration (OCR A-Level Biology A): Flashcards
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Define transpiration
Define transpiration
Loss of water vapour from leaves through stomata
Define stomata
Define stomata
Pores in leaf epidermis surrounded by guard cells
Effect of temperature on transpiration
Effect of temperature on transpiration
Increases rate (very high temps close stomata)
Effect of humidity on transpiration
Effect of humidity on transpiration
Higher humidity reduces gradient, decreases rate
Effect of air movement on transpiration
Effect of air movement on transpiration
Removes water, maintains gradient, increases rate
Effect of light on transpiration
Effect of light on transpiration
Darkness closes stomata; low threshold, rarely limiting
Define potometer
Define potometer
Measures water uptake (approximates transpiration)
Why cut stem underwater in potometer
Why cut stem underwater in potometer
Prevents air entering xylem/prevents airlocks
Volume formula for water absorbed (potometer)
Volume formula for water absorbed (potometer)
πr² × distance moved
Transpiration refers specifically to what process
Transpiration refers specifically to what process
Evaporation from leaves, NOT movement up stem