Strictly speaking, the leaves
are located under the rays of the sun, but you wouldn't say it that way, because the action you want to portray is the leaves doing
something within the area of sunlight.
You've got them glowing. The picture that leaps to my mind is that they're radioactive or something.
So what are you trying to say? What season is it? I'd not write the sentence in such a way that the leaves are doing the action, but rather I'd write it from the standpoint of the sun causing a reaction to the leaves. You
could have them doing it, though, such as:
The birds are singing, the breeze is blowing, and the leaves are dancing in the sun.
It's your use of the word
glowing that confuses me.
But you could also have the leaves responding to the sun. For instance:
the sun captured the sparkle of color on the leaves. Or the
sunshine reflected the stunning reds and oranges of fall.
But I might not be addressing the purpose of your original sentence, so I'll see what you have to say to this much.
To give you a short answer, I would not use "under the sun" in your sentence. And I would re-consider using
glowing.
AngelEyes