Subject: do trees take in water during the day or night

I am in a science fair and I did try to find out the answer but I couldn't 
find anything. My mom and day even tried to help me. I am using celery for 
my experiment, I am putting celery in a cup with water and food coloring 
and placing one in the light and one in the dark but I wanted to read on 
how trees water first.  Thank You. 

Re: do trees take in water during the day or night