The roots of the plants on land help them absorb water and nutrients from the soil. It also helps in anchoring themselves in place. Aquatic plants grow in water. While some grow in fresh water, others flourish in salty water. These plants often grow more quickly than plants on land.
Some float freely on water surface, some grow entirely submerged while some prefer shallows near the shore. The stems of such plants are flexible and may have hollow, air filled pockets. There are air cells in their leaves and leaf stalks, keeping them at sunlit surface. Aquatic plants have two different sets of leaves – broad ones that float and feathery ones that stay submerged.
Most water plants do have roots to hold them in place but not all. The roots help prevent drifting to some other place along with water where conditions may or may not be favorable to their growth. Beautiful water lilies have long stalks that connect leaves and lilies to their anchoring roots. Some floating species like the water hyacinth has thickly branching roots used for absorption. Root system of aquatic plants also helps the plants branch out and spread.
A few species like the duck weeds can manage without roots. Such plants absorb water through their leaves. Algae and sea weeds too do not have roots. Most of the nutrients that they need can be obtained from the water.Certain species like the arrowhead and water chestnut have tuberous food-storing roots. Edible water chestnut is actually a vegetable. Broadleaf Arrowhead which is also called as Indian potato produces edible tubers which are relished by many.