How is carbohydrate storage different in onion then potato?

Carbohydrate storage in onions primarily occurs in the form of fructans, which are polymerized fructose molecules. In contrast, potatoes store carbohydrates mainly as starch, a polysaccharide composed of glucose units. This difference reflects their distinct functions in the plant; onions use fructans for water retention and energy storage in their bulb, while potatoes rely on starch as a dense energy reserve for growth and sprouting.