The diagram below represents an experiment to demonstrate a certain phenomenon in a green plant (a leafy shoot fixed by rubber tubing to a glass tube standing in mercury): The diagram below represents an experiment to demonstrate a certain phenomenon in a green plant (a leafy shoot fixed by rubber tubing to a glass tube standing in mercury):
Define Transpiration.
Topic: Transpiration
Answer
TRANSPIRATION is the loss of water in the form of WATER VAPOUR from the AERIAL parts of a plant — mainly through the stomata of the leaves, and to a smaller extent through the cuticle and the lenticels.
Two elements must appear: the water is lost as VAPOUR, and from the AERIAL parts.
VAPOUR distinguishes it from GUTTATION, which gives liquid DROPS through hydathodes. AERIAL rules out the roots, which ABSORB water rather than losing it — which is why "all parts of the plant" is a wrong definition.
The three kinds by amount: STOMATAL about 90%, CUTICULAR small, LENTICULAR least.