factors affecting rate of transpiration Flashcards
what are the four factors that affect the rate of transpiration?
- air humidity
2, air temperature - wind/air movement
- light intensity
how does air humidity affect the rate of transpiration?
a rise in air humidity decreases the rate of transpiration
how does air temperature affect the rate of transpiration?
a rise in temperature increases the rate of transpiration
how does wind/air movement affect the rate of transpiration?
higher air movement increases rate of transpiration
how does light intensity affect the rate of transpiration?
higher light intensity increases the rate of transpiration
why does the rate of transpiration decrease with a rise in air humidity?
concentration of water vapour in air increases, decreasing concentration gradient between intercellular air spaces and atmospheric air. rate of diffusion of water vapour through stomata decreases
why does the rate of transpiration increase with a rise in air temperature?
rate of evaporation of water from surface of mesophyll cells increases, higher concentration of water vapour in intercellular air spaces increases the water vapour concentration gradient between intercellular air spaces in leaf and the air. rate of diffusion of water vapour through stomata increases
why does the rate of transpiration increase with higher wind/ air movement?
wind currents sweep away water vapour outside the stomata, increasing water vapour concentration gradient between intercellular air spaces in the leaf and the atmospheric air, increasing the rate of diffusion of water vapour through the stomata
why does the rate of transpiration increase with higher light intensity
in sunlight, photosynthesis in guard cells can occur. the stoma opens wider for more diffusion of water vapour