Question

why lower surface of fixed hydrophytes does not have stomata.​

Answer 1

All surfaces of the leaf have some amount of stomata for regulating gas exchange for photosynthesis. However, the lower epidermis (the underside of the leaf) has more, because it is more often in the shade and so it is cooler, which means evaporation won't take place as much.

Answer 2

Answer:

Stomata are meant for gaseous exchanges for two physiological processes i.e photosynthesis and respiration. They also allow transpiration . In lotus the leaves float on the surface of water. Theis lower surface is in touch with water and only upper surface is exposed. So all the three above mentioned functions are performed by stomata which are restricted to upper surface only.

Thats why lower surface does not need and it does not have stomata