Introduction 

Non-vascular terrestrial plants that thrive in damp environments are known as bryophytes. Mosses, hornworts and liverworts are among them. They help regulate ecosystems by acting as a buffer for other plants near bryophytes and benefit from the water and nutrients they collect. There are nearly 25,000 bryophytes species. Some bryophyte species are among the earliest to take root in open places. 

Bryophytes

Bryophytes are excellent indicators of habitat quality because many plant species in this category are sensitive to levels of moisture in the atmosphere, which are lower in disturbed environments due to reduced shade. Bryophytes do not produce seeds or flowers. The male gametes produce in the male reproductive organ (anthredia) have flagella and need water to reach the female sex organ (archaegonia) thus fertilisation is facilited by water so these are known as amphibians of plant kingdom.

Characteristics Of Bryophytes

• Terrestrial plants are non-vascular (they lack vascular tissue) even though they have specific mechanisms for water transfer 
• Bryophytes are mainly found in wet areas, although they can also be found in many habitats, including deserts, the arctic and high elevations. Bryophytes can live in conditions where vascular plants cannot because they do not rely on root systems for nutrition intake (e.g., on the surface of rocks)
• Bryophytes have unbranched sporophytes (the diploid form of the plant) that produce a single spore-producing capsule (sporangium). Furthermore, the sporophytes are nutritionally dependent on the gametophyte and develop within the female sex organ (archegonia)
• All bryophytes have a dominant gametophyte stage in their life cycle. The plant is haploid at this point and the sex organs that create gametes are developing. Bryophytes differ from many other plant species in that they can stay in this stage for a long time

Life Cycle of Bryophyte

The main plant body of a bryophyte is a gametophyte (haploid). The haploid gametophyte and the diploid sporophyte have alternate generations in the bryophyte life cycle. During the gametophyte stage, the specialised sex organs, the antheridia (male) and archegonia (female) produce haploid gametes (male and female). Flagellated sperm swim through the water.

When two haploid gametes (sperm or antherozoids and egg) combine to form a diploid zygote, a diploid zygote is created. The zygote grows inside archegonia and forms a diploid sporophyte.this sporophyte remains attached to the gametophytic plant body and is dependent on the gametophyte for water and nutrients. Through meiosis, mature sporophytes produce haploid spores in the sporangium. In favourable climatic conditions, these spores disperse and develop into new gametophytes.

Importance or Uses of Bryophytes

Bryophytes can be used as seedbed material, fuel, medicines and food sources, pesticides, nitrogen fixation, moss gardening, waste treatment, construction, clothing, furnishing, packing, genetic engineering and soil conditioning and culturing. Antibacterial, antifungal, cytotoxic, anticancer and insecticidal properties of bryophytes’ active ingredients are widely used in medical and agricultural fields.

1. Medicinal uses:
   • Sphagnum has great absorptive power and antibacterial properties, it is used in surgical dressings to fill absorptive bandages in place of cotton to treat boils and wound discharge
   • Marchantia has been used to treat tuberculosis of the lungs and liver diseases.
   • In treating acute bleeding and eye infections, dry sphagnum decoction is employed
   • Antiseptic and preservative peat-tar is used in many products. Skin illness is treated with Espagnol, which is a peat-tar distillate
   • Polytrichum species have been found to dissolve kidney and gallbladder stone
   • Antibiotics can be derived from antibiotic-producing bryophytes
2. In research: In the science of genetics, mosses and liverworts are used. Liverworts have been identified for the plant’s sex determination process.
3. Packing material: Dried mosses are a great way to protect fragile items like glassware and bulbs. Because they have a water retention capacity, they can transport living materials such as plant cuttings and seedlings.
4. Food: Herbivorous animals, birds and other mammals feed on mosses.
5. As Indicator plants: Some bryophytes grow in a specific environment and can be used to determine the soil’s acidity and basicity. Polytrichum, for example, showed soil acidity; Tortella species, on the other hand, thrive on soils rich in lime or other bases and appear as calcicoles.
6. In seedbeds: It is used to root cuttings in hotbeds, greenhouses, and nurseries because of its water-holding capability. Sphagnum is also utilised to keep the high soil acidity that certain plants require.
7. Peat formation: Peat moss is another name for Sphagnum moss. Peat is created by delaying the breakdown of organic matter. Peat is a dark-coloured substance formed by the slow compaction and carbonisation of partially degraded plant debris in bogs.

• It is employed as a source of energy
• The lower layers of peat form coal
• Peat is also used to make ethyl alcohol, ammonium sulphate, ammonia, colour, paraffin, tannins, and other products
• In horticulture, it increases soil texture

8.Formation of stone: The travertine rock formations are often employed as a construction material

Classification Of Bryophytes

Bryophyta is divided into three classes-  The liverworts (Hepaticopsida), the hornworts (Anthocerotopsida) and the mosses (true Bryopsida).

1. The word “hepatico” means “liver.” Hepaticopsida includes liverworts, which are a kind of bryophyte. They prefer to live in damp rocks and damp soil. Their chances of drying are much lower because they live near water. Liverworts are tiny plants with flattened stems, undifferentiated leaves and single-celled rhizoids. The presence of membrane-bound oil bodies within the cells of liverworts distinguishes them from other bryophyte species.Asexual reproduction in liverworts takes place by fragmentation of thalli, or by the formation of specialised structures called gemma (sing. gemma). Gemmae are green, multicellular, asexual buds, which develop in small receptacles called gemma cups located on the thalli. The gemmae become detached from the parent body and germinate to form new individuals.

This group further divides into four orders: Marchantiales (e.g., Riccia, Marchantia), Sphaerocarpales (e.g., Sphaerocarpos), Calobryales (e.g., Calobryum) Jungermanniales (e.g., Pellia).

2.Anthocerotopsida is a type of Anthocerotopsida that lives (Hornworts). Hornworts are what they’re called. Anthocerotales is the only order it has. Anthoceros, Megaceros and Notothylas are some examples of these creatures. In various areas, Bryopsida and Hepaticopsida are slightly more evolved than this group of bryophytes. The gametophyte is lobed and irregular in appearance from a distance. 

Except during the early stages of growth, the sporophyte is not dependent on the gametophyte for nourishment or protection. Antheridia and archegonia are a little submerged in the gametophytic tissue. Hornworts get their name from the sporophyte, which develops into a long horn-like structure. The gametophyte, on the other hand, is a green-bodied, flat plant. The majority of hornworts can be found in wet areas (for example, tropical climes), garden soils or tree bark.

3.Bryopsida is a phylum of the Bryopsida (Mosses). Moss is a common name for them. Most mosses, like liverworts, like moist conditions. Unlike other bryophytes, they thrive in moderately dry settings. Mosses, on the other hand, require water to reproduce, which is why they frequently form cushions or mats. Funaria, Polytrichum and Sphagnum are some examples. 

Mosses are clumpy, green plants that grow in wet areas away from direct sunshine. Mosses are distinguished by leaves that are only one cell wide and are linked to a stem that transports water and nutrients. Mosses can absorb a lot of water and have been utilised for insulation, water absorption, and as a source of peat in the past.Vegetative reproduction in mosses is by fragmentation and budding in the secondary protonema. In sexual reproduction, the sex organs antheridia and archegonia are produced at the apex of the leafy shoots.After fertilisation, the zygote develops into a sporophyte, consisting of a foot, seta and capsule. The sporophyte in mosses is more elaborate than that in liverworts. The capsule contains spores. Spores are formed after meiosis. The mosses have an elaborate mechanism of spore dispersal.

Conclusion

Bryophytes are low-maintenance plants. They are the essential plants that may be found on land. Bryophytes come in three different types. Mosses, liverworts and hornworts are examples. The scientific name for this group of plants without water-moving tissues is Bryophyta. They also have a wide range of applications and play an essential function in the environment.