Transpiration is said to be a necessary evil in plants. It helps the plant to maintain an ideal temperature reqd for various biochemical reactions. Moreover the Transpiration pull is also said to have a role in water transport through the xylem.
Evaporation loss of water in the form of vapours from the aerial plant besides the loss of water vapour in the transpiration, exchange of carbon dioxide and oxygen in the leaf also occurs through pores called stomata
Transpiration is important as it produces a suction pressure which helps the plant in pulling water and minerals from soil and also it helps in rain by adding more water in the atmosphere