Stomatal Transpiration: Water vapour diffuses out through minute pores (stomata) present in soft aerial part of plant is known as Stomatal Transpiration. Of the total water loss, near about 85 – 90% of water is lost by the stomatal transpiration.
Lenticular Transpiration: Sometimes water may evaporate through certain other openings present on the older stems. These openings are called Lenticels and the transpiration that takes place through the term is known as Lenticular Transpiration. The water lost by lenticular transpiration was about 0.1% of the total transpiration loss.
Cuticular Transpiration: Loss of water may also take place through the cuticle, but the amount so lost is relatively small and makeup only about 5 to 10 percent of the total transpiration. This type of transpiration depends upon the thickness of the cuticle and presence or absence of wax coating on the surface of the leaves. Xerophytic plants generally have a very thick cuticle and wax coating on the leaves and stem in order to check cuticular transpiration.
Of the total water loss, near about 85 – 90% of water is lost by the stomatal transpiration. Hence, the correct answer is option a.