When changing containers I had the opportunity to observe the roots.
Here are two photos of the same plant taken at different times.
Some factors
Air temp is 80+F.
Container is the same temperature as air temp. Container is in the shade.
Note the nice root structure.
.
Healthy roots in the shade
by
Hostafarian,
on Flickr
.
Here is the same plant .
Air temp is 80+F
Container temp is 120-130F.
Half the container is in direct sun .
Note the distinct area where no roots grow.
Can you tell which side was in the sun?
,
Untitled by
Hostafarian, on Flickr
.
Untitled by
Hostafarian, on Flickr