Lesson 2 ·Class 10 · Transpiration · Sort Lab
Stomatal, Cuticular and Lenticular
Three routes out, very unequal in size.
Sort each statement by the kind of transpiration it describes.
Sorted 0/8
All items sorted — check each bin.
Free play — sort every item into the bin it belongs in; each correct drop tells you why. Switch to when you're ready to test yourself.
Only the stomatal route can be regulated. The other two carry on regardless, which is why they set a floor below which water loss cannot fall.
What this lesson covers
Challenges to clear
- Fill the Stomatal bin correctly.
- Sort every statement.
- Fill the Lenticular box — the small loss through woody stems.
The task
Sort each statement by the kind of transpiration it describes.
What this lesson covers
- Stomatal — Through stomata: Accounts for the great majority of a plant's water loss (By far the largest route — which is why controlling the stomata controls transpiration.); Occurs through pores flanked by two guard cells (The guard cells open and close the pore, so this route is regulated.); Much greater from the lower surface of a dorsiventral leaf (There are more stomata underneath — which the cobalt chloride paper experiment shows directly.)
- Cuticular — Through the cuticle: Occurs through the waxy layer covering the leaf surface (Unavoidable, but small.); The thicker this layer, the less water is lost (Stated as a rule in the book, and it is why desert plants and evergreens have thick cuticles.); Cannot be controlled by the plant at all (There is no pore to close — it just seeps through.)
- Lenticular — Through lenticels: Occurs through small openings in woody stems (Lenticels are gaps in the bark that also allow gas exchange.); Contributes the least of the three (A small but continuous loss, and it continues even after the leaves have fallen.)
Hint
Only the stomatal route can be regulated. The other two carry on regardless, which is why they set a floor below which water loss cannot fall.