Question

State four differences between transpiration and guttation.

Answer 1

The water for the metabolic activity and growth of plants are absorbed by the roots. However, only a small quantity of the absorbed water is used. The majority of the water taken up is lost by processes called Transpiration and Guttation.

Complete answer: The process of loss of water in the form of water vapour from the aerial parts of the plants is known as transpiration. The process can take place through the stomata, cuticle or lenticel. Various environment factors like wind speed, light, humidity, temperature affect transpiration.
Guttation, on the other hand, is the process by which xylem sap is exuded from the tips of certain plants like grasses. The exudation occurs from certain organs called hydathodes.
The differences between these two processes can be listed as below:

Basis of difference	Transpiration	Guttation
Occurrence time	During the day.	During the night.
Mode of loss of water	Water is lost as water vapour.	Water is lost as liquid water.
Site of the process	Transpiration can occur through stomata, cuticle or lenticel.	Occurs through hydathodes.
Influence of temperature	Transpiration occurs when temperature is high.	Guttation occurs when temperature is low.

Additional Information: Transpiration and Guttation help to get rid of the excess water in plant bodies, otherwise the cells will burst. Both these processes result in permanent loss of water from the plant body.
The water lost in guttation is essentially a solution because it contains salts dissolved in water. The hydathodes are glands that secrete the solution. The process derives its stimulus from root pressure. since guttation takes place with the help of root pressure, it occurs only in small plants, otherwise huge amounts of pressure will be required for guttation to occur in big plants and trees. Hydathodes are pores through which guttation takes place. They cannot open or close like the stomata.
Transpiration occurs due to transpiration pull. Water is absorbed by the roots. Simultaneously, water is lost from the leaves during day time. This creates a pull in the xylem vessels through which the lost water is replaced. This process is called the transpiration pull. The majority of transpiration takes place through the stomata.

Note: Transpiration and guttation are indispensable processes to the well being of plant life. Transpiration helps to keep the plant cells rigid, maintains water balance, conducts water and minerals to different plant parts. Guttation, on the other hand, only balances out the amount of water in plants.