all plants store reserve substances in order to survive times without photosynthetic activity

Problem: soluble small molecules (mono-/disaccharides) are quickly available for energy production, but high concentration would make the cytoplasm too concentrated (osmotic potential -> trugor), thus not suitable for permanent substance storage in large quantities

Solutions:

1. few plants do store greater amounts of dissolved sugar inside the vacuole (sugar cane, sugar beet)

2. polymers of sugars (polysaccharides) are large molecules units that are not soluble (potatoes, cereals)

3. sugars are transformed into fats (like nuts)