Economic importance of bryophytes has been demonstrated since the stone age. Today, these plants attract attention from environmentalists, botanists, industrialists, horticulturists, and pharmacists due to their several ecological and economic benefits.
Bryophytes include Liverworts (Hepaticopsida), with over 300 genera and 6,000-10,000 species; Hornworts (Anthocerotopsida), with about half a dozen genera and around fifty species; and Mosses (Bryopsida), with over 680 genera and approximately 15,000 species, of which most of the species at least consist some kind of ecological or economic importance.
Bryophytes in plant succession
Mosses stand out among bryophytes as potent participants in the process of ecological succession. They thrive in locations that are nutrient-deficient and where other plants struggle to survive.
Once they perish and decompose, they contribute to the formation of humus, enhancing soil fertility. Consequently, the accumulated organic-rich soil becomes conducive for microorganisms.
These microorganisms foster increased nutrient availability, creating an environment suitable for the growth of higher plants.
Key species falling into this category include Caphalozia media, Isopterygium elegans, Lepidozia reptans, Pellia epiphylla, and Tetraplis pellucida.
Bryophytes in pollution monitoring
Bio-indicators encompass all organisms that reflect environmental quality through alterations in their morphology and physiology.
In contrast, bio-monitors offer a comprehensive range of qualitative and quantitative insights. The practice of utilizing organisms to assess environmental conditions is termed bio-monitoring, with the selected organisms referred to as bio-monitors.
These chosen organisms are capable of amassing pollutants, remain consistently present year-round, are straight forward to capture and identify, exhibit relative immobility, and have a widespread distribution.
The accumulated pollutants can be conveniently gauged by analyzing these organisms, furnishing data about the extent of pollutant deposition.
Bryophytes as bio-indicators of water pollution
The straightforward structure of bryophytes makes them more susceptible to the impacts of polluted water compared to other organism groups.
Polluted water not only influences the benthic and marginal soils but also directly affects aquatic bryophytes and, either directly or indirectly, those bryophytes growing on its banks.
Bryophytes can absorb water through rhizoids or their entire surface, or both. Water movement within a bryophyte occurs via the central strand, the cell’s free space, cell-to-cell movement, or external capillary space.
Consequently, water pollution significantly affects various aspects of bryophyte life, including external appearance, internal structure, fertilization, spore production, and physiological processes.
Kumar and Sinha (1989) have observed that bryophytes are more sensitive to water pollution compared to air pollution. Saxena and Glime (1991) have put forth arguments supporting the use of aquatic bryophytes as pollution indicators.
Empain (1967) and Trollope and Evans (1976) have suggested that bryophytes offer comprehensive insight into pollution within a system. Some aquatic bryophytes with higher tolerance to pollution have been recommended for monitoring pollution levels in water. These species include:
- Amblystegium riparium: A widely distributed moss found in nutrient-rich running or stagnant water, including sewage.
- Eurhynchium riparioides: A moss limited to northern regions of the world, often found in waters with pollutants and heavy metals.
- Fontinalis antipyretica: A moss with a restricted distribution in the north, found in both stagnant and flowing waters.
- Fontinalis squamosa: Also limited in distribution, with reported details on pollutants and heavy metals.
Specific bryophytes along the banks of the Ganga River have been highlighted in studies by Pandey et al. (1986), Sinha (1988), and Kumar and Sinha (1989) in relation to river water quality:
- Riccia gangetica: A pollution-tolerant species with well-developed tuberculate rhizoids and marginal scales in highly polluted areas. It’s a monoecious species.
- Riccia frostii: A pollution-sensitive species found in less polluted sites. Its sensitivity stems from smooth-walled rhizoids, absence of scales, and distinct male and female plants.
- Funaria hygrometrica: Thrives in sites with cremations, where benthic and marginal soils are rich in phosphorus and calcium.
- Physcomitrium indicum: A moss that absorbs heavy metals.
Pandey et al. (2001) found that bryophytes growing along the Ganga River banks accumulate high levels of heavy metals like chromium, zinc, and nickel.
HermannSchachner, Wikimedia Commons / Public Domain]
Bryophytes as bio-indicators of air pollution
Bryophytes have proven to be effective indicators of air pollution due to their high sensitivity to it. Air pollution can lead to the creation of “moss deserts” and compel many delicate species to withdraw.
They are extensively employed for assessing heavy metal air pollution, especially in urban centers and areas surrounding power plants and metal industries. Heavy metals like lead, chromium, copper, cadmium, nickel, and vanadium accumulate within their cell walls.
Air pollutants also impact the habitat and growth patterns of bryophytes. Sensitivity to air pollution escalates from ground-dwelling (terricolous) to those growing on rocks (saxicolous) and trees (corticolous).
The early stage of moss growth, known as the protonema, is more susceptible to pollutants than its mature gametophores (Gilbert, 1969). Daly (1970) noted that certain bryophytes can endure higher pollution levels on stone walls compared to tree trunks.
Some such species include Tortula princeps, Bryum rubrum, Ceratodon purpureus, and Pohlia cruda. Bryophyte species that are sensitive to air pollution encompass Ulota crispa, Platydictya subtilis, Paraleucobryum longifolium, and Frullania muscicola.
Bryophytes in Formation of Peat
Peat is a brown or dark-colored material formed through the gradual compression and carbonization of partially decomposed plant matter in bogs.
Sphagnum, an aquatic moss, secretes acids into the water as it grows, creating conditions that are unfavorable for decomposing organisms like bacteria and fungi.
The lack of oxygen and decomposing microorganisms slows the decay of dead material, leading to a significant accumulation over the years, which is known as peat, hence Sphagnum’s name, peat moss.
Peat is used as fuel in Ireland, Scotland, and Northern Europe. It is also utilized in the production of various products such as ethyl alcohol, ammonium sulfate, peat tar, ammonia, paraffin, dyes, tannin materials, and is used in horticulture to improve soil texture as well as in surgical dressings.
Bryophytes in Medicine
Some bryophytes are used medicinally for various ailments, including:
- Pulmonary tuberculosis and liver conditions—Marchantia species,
- Acute hemorrhage and eye diseases—decoction of Sphagnum.
- Kidney and gall bladder stones—Polytrichum commune.
- Antiseptic properties and wound healing—Sphagnum leaves and extracts from certain bryophytes such as Conocephalum conicum, Dumortiera, Sphagnum protoricense, and Sphagnum strictum.
The economic value of bryophytes is evident in roles such as erosion control, environmental bioindicators, material for seed beds, fuel, medicines, food sources, pesticides, nitrogen fixation, moss gardening, waste treatment, construction, clothing, furnishing, packaging, genetic engineering, soil conditioning, and cultivation. These contributions hold immense value in terms of sustainability.
Economic importance of bryophytes with special reference to Sphagnum
Information about the diverse economic significance of bryophytes is relatively limited. Despite being utilized in traditional herbal and food remedies among various tribal communities across continents such as Africa, America, Europe, Poland, Argentina, Australia, New Zealand, Turkey, Japan, Taiwan, Pakistan, China, Nepal, and India, there is a scarcity of comprehensive knowledge regarding the medicinal properties of bryophytes.
The commonly employed bryophytes include Marchantia, Sphagnum, Polytrichum, Conocephalum, Climacium, Hylocomium, and Hypnum.
- Notably, Sphagnum, a genus encompassing peat mosses, holds paramount economic importance within the realm of bryophytes.
- Sphagnum is utilized in seed beds and greenhouses as a rooting medium due to its exceptional water absorption and retention capabilities.
- Sphagnum, along with other mosses, forms a thick, compressed layer that partly decomposes on top of mineral soil. This accumulation, known as peat, can be harvested in blocks, dried, and used as a fuel source for cooking and heating.
- Its application extends to packing bulbs, cuttings, and seedlings for transportation, as well as maintaining the requisite high soil acidity for specific plants.
- Extensive harvesting of Sphagnum takes place globally, with its subsequent use prevalent in the nursery industry of numerous countries.
- During World War I, Sphagnum was employed on a large scale as wound dressing due to its sterile, acidic tissue, which functions as an antiseptic and absorbent.
- By-products of Sphagnum peat include paraffin, acetic acid, and ammonia. It is utilized as stable litter and bedding material.
- Sphagnum’s ecological significance is profound, contributing to the biological reclamation of waterlogged areas. It acts as a pioneer species, settling in hollows that would otherwise remain sterile water bodies.
- The spread of mosses over surrounding vegetation can lead to waterlogged conditions, resulting in the demise of adult trees and hindering the growth of young seedlings, causing extensive forest damage.
