Presence of carotene in Leaves and in Citrus Fruit

[BillAngel]

The fruit of the lemon tree starts out as green in color, and then ripens into a bright yellow.
Likewise, the leaves of a number of trees are green when they are alive, and then change color in the autumn to bright yellow. I've read that the yellow color in both autumn leaves and ripe lemons is due to the present of carotene. So my question is, does carotene play the same role in the biochemistry of leaves as it does in the biochemistry of lemons? I've also read that carotene is present in leaves to protect the leaves from the byproducts of photosynthesis, which would otherwise cause damage. This question is related to the question as to whether there is an evolutionary advantage for the fruit of the lemon to be yellow. Does the yellow color of the fruit aid somehow in the reproduction of the plant?
Thanks for any replies.
Bill Angel

[JackBean]

it's not carotene (which is red), but carotenoid (group of compounds)