through my reading of plants, Ive read that plants like colder temps depending on what area you get them from.
if you look at terrestrial plants, such as the palm tree vs the birch tree, you can see that the plants have addapted to different temps.
I dont know what temps the birch likes, but you find them more in the colder regions. palms like the hotter weather. if you keep a palm outside in michigan winters, it will die.
so, if you see that a plants likes X degrees, it will more than likely grow better in that temp.
from what I read, a general rule for under water plants is 70-76