Question

Generally stomata are found on the lower surface of a leaf. Thus, approximate percentage of transpiration through abaxial surface is
A. 47 %
B. 57 %
C. 67 %
D. 97%

Answer 1

Hint: Stomata are the openings which are present on the epidermis of the leaf and play an important role in photosynthesis, gaseous exchange and transpiration. These are seen mostly on the lower surface of the leaf. It consists of small pores called stomata that are surrounded by guard cells. In dicots, the stomata is bean shaped and in monocots, it is dumbbell shaped.

Complete answer:
As I mentioned, leaves contain numerous stomata on the lower surface and they play an important role in transpiration. The leaf usually has a lower surface and upper surface. The lower surface is called abaxial and the upper surface is called adaxial. In general, more numbers of stomata are present in the abaxial surface i.e the lower surface. The transpiration can occur through stomata, cuticles and lenticless. The stomata contribute about 50 to $97\%$ towards transpiration, cuticles account for $3\%$ of transpiration whereas lenticels account for a very low rate of transpiration. The highest rate of transpiration is through the stomata and that too the lower surface because it contains abundant stomata.

Based on the above explanation, the correct option is D

Note:
Transpiration is the process where the water is lost in the form of vapour. This is the process that keeps the cell turgid and cools the leaf surface and also maintains the water balance. The remaining water is lost through guttation where water is lost in the form of droplets.