Why the upper surface of the leaves are more green and shiny than the lower surface?

Photosynthesis:

As we know, the plants produce their own food by Photosynthesis. The uptake of Co2 and Water to produce Carbohydrates with the help of Sunlight by using Chlorophyll is called Photosynthesis. The Chlorophyll is a green pigment present on the leaves of the plants. The upper surface of the leaves are more exposed to sunlight than the lower surface. Hence, in order to produce more food, the chlorophyll content is present more on upper surface than the lower surface. 

Transpiration:

The loss of water from plants in the form of water vapor is called transpiration. To prevent the loss water, the leaves are covered with shiny, waxy coating layer called cuticle. As the upper surface of the leaves are over exposed to sunlight than the lower surface, the upper surface is covered with a thicker cuticle than the lower surface. Hence the upper surface of the leaves are more shiny as compared with the lower surface.