Aquatic plant

Some plants live in water.

They grow in lakes and rivers. These plants make the air we breathe.

Fish and bugs use them for homes. Some plants float on top. Others stay under the water. Some plants have leaves that reach up to the air. They can be very big or very small. Do you like water plants?

Aquatic plants live in water. They can grow in lakes or rivers. Some live in salt water. These plants are very helpful. They give fish and bugs a place to hide. They also make oxygen through photosynthesis. This is the way plants use light to make food.

To live in water, plants need special parts. Many have aerenchyma. These are lightweight cells that help them float. Some plants have leaves that stay under the water. These leaves are often thin or split into small parts. This helps them move in fast rivers.

Plants can be big or small. Large plants are called macrophytes. You can see them with your eyes. Small plants are called microphytes. These are so tiny you need a microscope to see them. Some plants stay on the bottom. Others float freely on the surface. Even the smallest duckweed is an aquatic plant.

Aquatic plants are special living things that thrive in water. They can grow in freshwater lakes and rivers or in salty ocean water. These plants are very important for the world's water homes. They provide cover for fish, insects, and amphibians to hide from predators. They also create food for animals that eat plants. Most importantly, they produce oxygen through photosynthesis. This process helps keep the water healthy for all living things.

Living in water requires a special way of working. Many plants have aerenchyma, which are lightweight internal cells. These cells act like tiny air pockets to help the plant float. Some plants have leaves that are split into many small parts. This shape helps them move through fast river water without being torn. Other plants have leaves that only have openings, called stomata, on the top. These openings let them breathe in carbon dioxide from the air.

Scientists have studied these plants for a very long time. We know that aquatic plants have appeared many times in history. There are at least 50 different times when plants evolved to live in water. One of the oldest fossils we have found is called Archaefructus. This fossil is about 125 million years old. This shows that plants have been adapting to water for a very long time.

There are many different kinds of aquatic plants. Large plants that you can see with your eyes are called macrophytes. Some macrophytes are emergent, which means they poke out above the water. Others are submerged, meaning they stay completely under the water. You might know water lilies, which have leaves that float on the surface. There are also tiny plants called microphytes. These are so small that you need a microscope to see them.

Nature shows us amazing variety in these water plants. The Bolivian waterlily holds a record for having a huge leaf. This leaf is the largest undivided leaf in the world. On the other side, the tiny duckweed is very small. Some plants, like the water soldier, even move up and down. They start at the bottom and float to the surface to flower. This shows how hard plants work to survive in their watery homes.

Aquatic plants, often called hydrophytes, are specialized vascular and non-vascular plants. They have adapted to live in aquatic environments, including both freshwater and saltwater. These plants are essential components of ecosystems like lakes, rivers, and wetlands. They provide vital cover for fish, amphibians, and aquatic insects. They also create a substrate for benthic invertebrates to live on. Through photosynthesis, they produce oxygen for the water. They also serve as food for various herbivorous wildlife.

To survive in water, these plants use unique biological mechanisms. A common adaptation is the presence of aerenchyma. These are lightweight internal packing cells that act like air pockets. This helps plants stay buoyant or float at the surface. Some plants also have finely dissected leaves. This shape helps reduce drag in moving river water. It also increases the surface area for exchanging minerals and gases. Some species, like Ranunculus aquatilis, even use two different leaf forms. They have dissected leaves underwater and entire leaves on the surface.

Floating-leaved plants have specific ways of breathing. Their leaves often have stomata, which are tiny pores, only on the top surface. This allows them to take in atmospheric carbon dioxide. Because they live in water, they do not risk dehydration through these pores. In fact, their stomata often remain in a permanently open state. Some aquatic angiosperms can also use bicarbonate from the water for carbon fixation. This is a trait not found in terrestrial plants. This allows them to thrive even in environments with low carbon levels.

Scientists classify these plants based on their morphology, or physical form. Large plants visible to the naked eye are called aquatic macrophytes. These are divided into several distinct growth types. Emergent plants grow in water but pierce the surface to reach the air. This allows them to be pollinated by wind or insects. Submerged macrophytes grow entirely underwater. Some are rooted to the bottom, while others are unrooted and free-floating. Floating-leaved plants have roots in the substrate but leaves on the surface. Finally, free-floating plants like water lettuce drift on the surface without being attached to the bottom.

Smaller aquatic plants are known as microphytes. These are microscopic and cannot be seen with the naked eye. They include phytoplankton, which are microscopic algae that drift with currents. They also include periphyton, which grow on the surfaces of rooted plants. Benthic algae live on submerged surfaces like mud or stones. Some are single-celled, such as diatoms, while others are multi-celled, like Spirogyra. These tiny organisms play a massive role in the aquatic food web.

History shows that aquatic plants have a deep evolutionary past. Aquatic vascular plants have originated on many different occasions. There are at least 50 independent origins within the angiosperms. This means different plant families evolved to live in water separately. One of the oldest known fossils is Archaefructus. This fossil is approximately 125 million years old. Evidence suggests that some of the earliest angiosperms were actually aquatic. While they are diverse, aquatic plants make up less than 2% of all angiosperm species.

Nature provides extreme examples of these adaptations. The Bolivian waterlily holds a Guinness World Record. It has the largest undivided leaf in the world. In contrast, the rootless duckweed is among the smallest. Some plants even change their position in the water column. The water soldier rests on the bottom as a rosette. In late spring, it slowly floats to the surface to flower. During this journey, it produces roots and daughter plants via rhizomes. Once flowering ends, the plant descends and its roots atrophy. This complex life cycle shows the incredible versatility of life in water.