Describe an experiment to show that more transpiration occurs in the lower epidermis than the upper epidermis of a plant leaf. 

Two identical photometers setup are each containing a single leaf from the same potted plant but one smeared with grease on the upper epidermis  and another with grease on the lower epidermis to prevent transpiration

Observation

The air bubble in the photometer where the leaf is smeared with grease on upper epidermis moves faster than that in which the lower epidermis is smeared with grease

Conclusion

When the upper epidermis is smeared with grease, transpiration occurs  through the lower epidermis. Thus transpiration is higher through the lower epidermis.