Re: what percentage of various plants are water

It will vary from over 95% of the fresh weight in plants such as lettuce and 
wax begonias to less than two percent for some seeds. Drying seeds to a low 
moisture content greatly extends their life in cold storage. 

In general, you would expect woody plants would have lower moisture contents 
than nonwoody ones. Succulent plants, such as cactus, usually have high water 
water contents. Cactus often contain 90 to 94% water when fully hydrated. 
Edible pads of prickly 
pear cactus average 85% water.  

Many aquatic plants, such as elodea, have  water 
contents (over 95%) because they do not need much supporting tissue 
such as xylem.

The table in the references gives water contents of common fruits and 
vegetables, such as banana (74%), white potato (79%), grapes (81%), pineapple 
(87%), celery (95%) and radish (95%).

The equilibrium water 
content of lumber varies greatly depending on the relative humidity of the 
air. 

References


Table of Water Content of Fruits and Vegetables


Re: how much water is in a watermelon?