This article contains 4 characteristics of aquatic plants but let us first know what an aquatic plant is. Everyone is familiar with plants that are on land but little is still known about plants that grow in water.
What is Aquatic Plant?
Aquatic plants are simply plants that grow underneath the water.
Definition of an aquatic plant according to Merriam Webster Dictionary,
“Aquatic plants are plants that grow in water (such as the water lily, floating heart, or lattice plant) whether rooted in the mud (such as a lotus) or floating without anchorage (such as the water hyacinth).”
Aquatic plants may be grouped as weeds when considered under the fact that these plants were not planted by any person and can be unwanted based on where they grow.
Aquatic plants can live in environments where their roots can be submerged underwater. Some benefits of these plants include the creation of important habitat and food sources for wildlife; filtering or trapping soil; and nutrients during runoff and absorption of nutrients.
But considering their unique characteristics and benefits from the land plants, they are not weeds. Aquatic plants include plants that have their roots in sediment with part or all of the plant underwater, as well as plants that float freely without connecting with sediments.
Aquatic plants may be in both marine and freshwater environments, including habitats such as wetlands, lakes, rivers, estuaries, coastal zones, irrigation systems, hydroelectric systems, and aquaculture facilities.
Aquatic plants can survive on land therefore they are many to live underwater. Done artistic plants are submerged underwater while since have their for underwater while their leaves float.
Aquatic plants vary greatly in type, with some being quite similar to common land plants while others are quite different. Aquatic plants are grouped into four common class types: algae, floating plants, submerged plants, and emerged plants. This is based on the positioning of their roots and leaves.
- Floating-leaved plants
- Submerged plants
- Emerged plants
Algae are the oldest and the most common type of aquatic plant, they are very small and have no errors, stem, or leaves. They are mostly found in the ocean and they make up the basis for the chain of the ocean. Examples of algae include lyngbya and musk grass.
2. Floating-Leaved Plants
Floating-leaved plants have their leaves floating on the top of the water while having rootless or roots with hair-like structures. If they have roots, the roots are not attached to the water’s bottom but can absorb water.
The leaves of these plants are flat and firm so they can absorb more sunlight as they cover the water, they help keep the water temperature cool for fish and wildlife reducing algae growth.
Floating-leaved plants can be found in fresh or daily water. They usually grow in areas where there is a little wave in the water. Examples of floating-leaved plants include various types of lilies and water hyacinths.
They could also include Pistia spp. commonly called water lettuce, water cabbage, or Nile cabbage.
3. Submerged Plants
Submerged plants also known as oxygenating plants are plants that are rooted in the water’s floor with most of their vegetation under the water enabling it to release oxygen to keep the water quality. Their leaves are usually thin and narrow. Examples of submerged plants include hydrilla’s and bog moss.
They also include stands of Equisetum fluviatile, Glyceria maxima, Hippuris vulgVulgarisgittaria, Carex, Schoenoplectus, Sparganium, Acorus, yellow flag (Iris pseudacorus), Typha, and Phragmites australis.
4. Emerged Plants
Emerged plants are plants that are rooted in the water’s floor with most of their vegetation above the water. These plants need constant exposure to sunlight for growth. These vascular plants often have deep and dense roots that stabilize shallow soils at the water’s edge.
They are also habitats for birds, insects, and other animals living near water. Emerged plants are also known as shelf pond plants. They grow mostly at riverbanks. Examples of emerged plants include knotweed and redroot.
Some species of emergent plants include the reed (Phragmites), Cyperus papyrus, Typha species, flowering rush, and wild rice species. Now let’s look at the characteristics of aquatic plants.
Characteristics of Aquatic Plants
We are going to look at the characteristics of aquatic plants holistically and individually i.e algae, emergent plants, submerged plants, and floating-leaved plants.
Aquatic plants have thin cuticles though most don’t need them. Cuticles prevent loss of water. Aquatic plants gave their stomata always open because they don’t need to retain water. Aquatic plants have stomata on both sides of their leaves.
Aquatic plants are supported by water pressure so they have less rigid structures. Some aquatic plants have their flat leaves on the surface since they need to float. For some Aquatic plants to float they need air sacs.
Aquatic plant roots are smaller than terrestrial plant roots enabling them to spread freely and directly into leaves. Aquatic plant roots are light and feathery since they do not need to prop up the plants. Aquatic plant roots are specialized to take in oxygen.
Permanently submerged aquatic plants absorb nutrients and exchange gases directly from the water.
Aquatic plants have their body full of empty spaces which represent channels to obtain oxygen so their roots can breathe correctly and from which air circulates from the atmosphere to the roots giving the plant the ability to float or be able to stay.
An example would be the case of trees like swamp cypresses that have special roots to breathe, called pneumatophores, which stick out of the water to reach oxygen. Another would be duckweed have a chamber under their leaves that are filled with air, which allows them to float.
Aquatic plants and algae do have a supersaturation of oxygen occurring during the daylight hours and consequent desorption of the oxygen to air resulting in oxygen depletion at night.
Though the global balance is a net production of oxygen, aquatic plants and algae produce oxygen through photosynthesis in the presence of sunlight and consume the oxygen through respiration.
Another important characteristic is the ability of these plants to adapt to waterlogged environments and swamps is their ability to perform a biochemical process that helps prevent the accumulation of toxic products that are typical of low oxygen or anaerobic media conditions.
Having looked at some characteristics of aquatic plants in general terms, let’s look at the characteristics of aquatic plants considering the groups of algae, floating-leaved plants, submerged plants, and emerged plants. With this, the characteristics of aquatic plants are as follows. Characteristics of;
- Floating-leaved plants
- Submerged plants
- Emerged plants
1. Characteristics of Algae
Algae are a special aquatic plant having some plant and animal characteristics. For example, most algae can carry out photosynthesize like plants, and they possess specialized structures and cell-organelles, like centrioles and flagella, found only in animals.
Algae can be either unicellular or multicellular organisms. Examples of unicellular algae are non-motile, rhizopodial, or coccoid. Examples of multicellular algae are colonial, palmelloid, dendroid, filamentous siphonous, and so on.
Some algae are found more in water especially in plankton with phytoplankton being a population of free-floating microorganisms composed of unicellular algae.
They don’t have roots, stems, and leaves but do have chlorophyll and other pigments for carrying out photosynthesis and they are found where there is adequate moisture, examples could be moist soil, moist rock surface, or moist wood. They also live with lichens in fungi
Algae perform reproduction in both asexual and sexual forms with the asexual form occurring in spore formation. Spore formation takes place by mitosis. Binary fission also takes place (as in bacteria). Though some also can be symbiotic and parasitic.
An example would be fungi. Asexual reproduction can also occur through the fragmentation of colonial and filamentous algae.
Algae reproduce sexually through the alternation of generations. Algae form a diploid zygote with two sets of chromosomes produced as a result of the fusion of differentiated sex cells.
The zygote develops into a sexual spore, which germinates when conditions are favorable to reproduce and reform the haploid organism having a single set of chromosomes. Algae are classified into seven divisions, of which five are in the animal (Protista) kingdom and two in the Plantae kingdom.
Algae cells can be organized in different ways, namely prokaryotic (eg: Myxophyceae), mesokaryotic (eg: Dinophyceae), and eukaryotic (other groups). Unlike floating-leaved aquatic plants, algae cells are covered by a rigid cellulose cell wall.
They have present in them, a nucleus and multiple chromosomes are observed in mitosis. The chlorophyll and other pigments occur in chloroplasts, which contain membranes known as thylakoids.
While carrying out chemosynthesis through obtaining energy from chemical reactions and nutrients from preformed organic matter. Algae flagella are arranged in the typical 9+2 pattern for microtubules.
Algae cells contain plastids and three classes of pigments, namely chlorophyll(a, b, c,d, and e), carotenoids (alpha, beta, gamma, and the theta carotenes, lycopene, lutein, flvicine, fucoxanthin, violaxanthin, astaxanthin, zeaxanthin, myxoxanthin), and phycobilins or biliproteins(phycocyanin, phycoerythrin, allophycocyanin).
Algae reserve food which includes mostly starch and oils (in Chlorophyceae starch; in Xanthophyceae and Bacillariophyceae chrysolaminarin and oils; in Phaeophyceae laminarin, mannitol and oils, in Rhodophyceae Floridian starch and galactan; in Cyanophyceae cyanophycean starch)
The entire thallus of Algae is formed off only parenchyma cells as there are no vascular and mechanical issues. There is the presence of holdfast, stipe, and lamina. Holdfast is used for attachment, stipe forms the axis, and lamina serves as the leaf-like photosynthetic part.
2. Characteristics of Emergent aquatic plants
An emergent plant pierces the surface so that it is partially exposed to air. This is major because the main aerial feature is the flower and the related reproductive process. The emergent plant can pollinate through the wind or by flying insects.
This can also be because photosynthesis can occur through the leaves of emergent aquatic plants more efficiently in air and these plants also compete with submerged plants. Some species, such as purple loosestrife, can grow in water as emergent plants but they are capable of flourishing in fens or simply in damp ground.
Emerged aquatic plants which a part of their body out of the water don’t have much resistance to losing water, these are quite different from plants that can survive in dry environments so they have waterproofing coatings on the leaves and the stem, they also have their stomata opened and arranged on the surface.
3. Characteristics of Submerged aquatic plants
Submerged aquatic plants may have a system that is attached to the substrate (e.g. Myriophyllum spicatum) or without any root system (e.g. Ceratophyllum demersum).
Helophyte is a type of aquatic plant that is partially submerged in water so that it regrows from buds below the water surface. Fringing stands of tall vegetation by water basins and rivers may include helophytes.
4. Characteristics of Floating-leaved aquatic plants
Floating-leaved aquatic plants usually have root systems attached to the substrate or bottom of the body of water that enables them to float on the water surface.
Free-floating aquatic plants that are found suspended on water subsurfaces have their roots not attached to substrate, sediment, or bottom of the water body.
Because of this, they are easily blown by air and provide breeding grounds for mosquitoes.
Why are aquatic plants useful?
Aquatic plants are very useful and the reason is that they are a hugely untapped reservoir of antimicrobial and functional compounds which could be processed into very functional food ingredients in producing novel dishes and miscellaneous products.
These untapped resources can also help in the production of life-changing pharmaceutical products. Aquatic plants and also produces oxygen which side the sustainability of water and improves water quality.
Emergent aquatic (vascular plants) have deep and dense roots that help in stabilizing shallow soils at the water’s edge. They also provide a habitat for birds, insects, and other animals living near water.
Submerged aquatic plants create habitats for underwater organisms like fishes and small invertebrates and are a food source for ducks and aquatic mammals. They also filter and trap the soil and nutrients during runoff and absorption of nutrients.