mexican sunflower leaves sometimes look stressed at night

Question

The leaves look stressed and down when I see them in the morning but later in the day they are nice and green. Is this normal?

Answer 1

It probably has to do with moisture and the way the plants handle dry environment, shutting down their processes during the hottest part of the day and the night -- that's when they look wilted -- then opening stomata, and moving moisture stored in their roots during the night into the plant tissues when the sun is shining.