Re: Why do some plants store some of the carbohydrates they produce?

Most plants produce more carbohydrates than they can use at any one time 
and the unused carbohydrates can be stored in many forms, starch and 
sucrose being the most frequently stored carbohydrates. Starch is a 
polysaccharide made up of many glucose molecules while sucrose is a 
disaccharide made up of a molecule of glucose and a molecule of 
fructose.  Some seeds contain carbohydrates in the form of cotyledons, or 
seed leaves, that nourish the developing embryo as it grows and emerges 
as a seedling and starts photosynthesizing and producing its own 
carbohydrates.  Some cereal grains have an endosperm made up of
carbohydrates that also nourish the developing embryo.  Some plants 
also store carbohydrates in their roots to mobilize and use at times when 
the plant is not photosynthesizing (i.e. a biennial plant, a deciduous 
shrub or tree).  The carbohydrates that plants are storing are stored for 
the use of the plant.  One of the main needs of a plant cell are the 
components necessary for making cell walls.  As each cell divides, a new 
cell plate must be made to separate the two nuclei into two distinct 
cells.  The major component of a plant cell wall, cellulose, is made of 
monomers of glucose that are bonded together similar to starch.  However, 
most mammals lack the enzyme necessary to break these bonds so that plant 
cell walls pass through most mammalian digestive tracts unchanged.  
Sucrose is generally not the most common carbohydrate being stored with 
one of the major exceptions being that sugarcane stores sucrose in its 
stems.  Sucrose can be easily transported through plants while starch, 
one of the more abundant storage carbohydrates found in plants, is 
usually not transported until it is hydrolyzed into glucose molecules. It 
is lucky for us that plants store excess carbohydrates because, by eating 
stored carbohydrates produced by plants, we survive by exploiting the 
carbohydrate storing property of plants.