Does transpiration bring any useful function in plant ?
Transpiration plays following useful functions in plants :

1. Ascent of sap - It is the pulling force that helps in the movement of water up the plant. 

2. Cooling effect - cools the leaf surfaces sometimes upto 10 to 15 degrees. 

3. Transport minerals from the soil to all parts of the plants.

4. Maintains the shape and structure of the plants by keeping the cells turgid. 

5. Supplies water for photosynthesis.