The diagram below represents a process in plants (a leafy shoot in a flask of water with a layer of oil on top, the whole standing on a weighing machine). The setup was placed in bright sunlight. Answer the following questions: The diagram below represents a process in plants (a leafy shoot in a flask of water with a layer of oil on top, the whole standing on a weighing machine). The setup was placed in bright sunlight. Answer the following questions:
Explain the term ‘Guttation’.
Topic: Guttation
Answer
GUTTATION is the loss of water in the form of LIQUID DROPLETS from the TIPS AND MARGINS of leaves, through permanently open pores called HYDATHODES situated at the endings of the veins.
Two elements must appear: the water is lost as LIQUID DROPS, and through HYDATHODES at the leaf tips and margins.
WHEN IT HAPPENS: at night or in the early morning, when the air is humid and the stomata are closed so transpiration cannot occur, but ROOT PRESSURE continues to push water upward. The water is forced out as visible droplets along the leaf edge.
THE CONTRAST to hold: TRANSPIRATION gives water VAPOUR through STOMATA, mainly by day; GUTTATION gives water DROPS through HYDATHODES, mainly at night.
The drops on grass early in the morning may be either guttation or DEW — dew condenses from the air, guttation comes from inside the plant.