why are the outside (tops) of leaves shinier and more vibrant than the underside (bottom) of leaves?

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why are the outside (tops) of leaves shinier and more vibrant than the underside (bottom) of leaves?

In: Biology

The bottom of leaves typically has the stoma which are like small vents, while the top is usually waxy which helps protect against the elements

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I’m going to answer with an analogue:

Imagine you’re building a solar panel. Do you put photocells on both sides? Of course not. Why? Because the sun only hits one side. You _could_ build out both sides but that would take extra cost with no real additional benefit.

For leaves, one side is optimized for sunlight because there is a net energy and nutrient cost for optimizing both side which isn’t justified by the increased photosynthesis. The development on the backside of the leaf is sufficient to maintain the durability of the leaf and not really much more than that. (There are example which counter this, because of course there are, but generally, this is the reason.)

The question and answers thus far are very focused on dicots.

Monocots don’t have to do tops and bottoms and can have stoma on both sides.