Yes it does. It only grows in excess due to mechanical stress.
The moonlight doesn't produce mechanical stress.
Proof?
...
You really want proof? Fine.
Plants don't move when there is no wind. Actually, that is very incorrect
Plants do not exhibit signs of physical damage. Their growth responses do
Nothing has been ever observed to move when there is moonlight (or any light) but no wind or other forces. Incorrect. Plants are always moving to some degree
And unless you've been hiding data, your microscope pictures did not show ANY damage to any of the cells in any of the plants. The excess collenchyma speaks for itself
I don't include growth to mean movement(ie. growth of excess cells on one side which causes a plant to appear to move). But you're right, I should clarify that normal movements such as flowers blossoming are excluded.
However your last point is incorrect. The excess collenchyma says nothing. All it says is that you have excess collenchyma and it might have been caused by exposure only to moonlight. Until you can show actual harm done to the plant (collenchyma growth isn't a response to damage, it's a prevention of damage) your conclusion is premature.
And you've failed to demonstrate that excess collenchyma growth actually harmed the plants in any way.
it is terribly metabolically expensive to make any at all. Excess takes away fom other parts of the plant.
Read the old plant by a fan experiments. Excess growth absolutely crippled them!
So? What, you think plants are somehow sentient and do things that are only beneficial to them if the energy payoff out-wights the risk? They respond to something. Animals do it too. An insect bites them, they scratch the bit area. Does that mean that scratching is beneficial? No, it's harmful.
I'm sorry but plants are no different than any other living thing: they can do things based on outside stimuli that are not helpful to them.