Leaf area means that only one side of the leaves or the leaves of plants, and the only means to be green. It represents the ability to synthesize light persists.
Area a refers to an area just one side of a sheet or in plants and means only the orders that are still green, which represents photosynthesis capability still exists.
The area is just one side of the blade or the disc in plants and means that only the leaves are green, indicating the ability to synthesis with a light is still on.