Question

Why does plants store food reserve in the root in the form of amylum instead of glucose?

Answer 1

To prevent a high osmotic pressure from ocurring.

Explanation:

The plant stores glucose as amylum (starch) to keep the osmolarity of the cell roughly the same. Amylum helps by combining a lot of glucose into one molecule. Imagine an amylum molecule consisting of 25 molecules of glucose. This amylum molecule counts as only 1 molecule for osmosis, whilst 25 seperate glucose molecules would count as 25.

Keeping the osmolarity around the normal value prevents an excess of water entering the cell and the movement of glucose out of the cell. This allows the cell to store the energy for later use