The majority of stomata are often situated underneath the leaves. This will prevent the plant from losing water. As a result, the sun cannot evaporate the water that maintains the appropriate structure of the stomata since they are well shielded from it in the shade of the leaf itself. However, we are aware that hydrilla plants are aquatic plants and do not have stomata. Since there is enough water and little risk of loss or gain, these plants don't need stomata. In such circumstances, gas exchange occurs through a central cavity that is filled with water.