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BBYCT-131: Biodiversity (Microbes, Algae, Fungi and Archegoniates)

BBYCT-131: Biodiversity (Microbes, Algae, Fungi and Archegoniates)

IGNOU Solved Assignment Solution for 2021-22

If you are looking for BBYCT-131 IGNOU Solved Assignment solution for the subject Biodiversity (Microbes, Algae, Fungi and Archegoniates), you have come to the right place. BBYCT-131 solution on this page applies to 2021-22 session students studying in BSCG, BSCBCH courses of IGNOU.

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Assignment Solution

Assignment Code: BBYCT-131/TMA/2021-2022

Course Code: BBYCT-131

Assignment Name: Biodiversity (Microbes, Algae, Fungi and Archegoniates)

Year: 2021-2022 (1st July 2021 to 30th June 2022)

Verification Status: Verified by Professor


Note: Attempt all questions. The marks for each question are indicated against it.


Q1.a) Describe the structure of RNA virus with suitable diagram.  (5)

Ans) RNA virus is the virus that has single-stranded as well as double-stranded RNA as its genetic material. Noticeable disease caused by RNA virus is (severe acute respiratory syndrome) SARS, influenza, common cold, Hepatitis B and C. All the RNA viruses have a capsid which is a protein coat (shell) that protects the nucleic acid. The shape of RNA viruses is spherical (icosahedral) or rod-like (helical). The rod-like RNA viruses have their capsids that packed the genome in the form of a coil that forms a long cylinder while the capsid present in icosahedral RNA virus forms a hollow space that encloses the genome. The capsids have other peptides or enzymes packed in them. The enzyme or peptide can be present in naked or surrounded by a lipid envelope. RNA viruses also contain other surface protein like glycoprotein that covers the viral envelop or capsid and is responsible for affecting the entry of viruses inside the host's cell. The genome of a typical viral RNA is responsible for the production of viral protein, and it acts as the genetic repository, acts as mRNA for translation, serves as a template for replication and assists the viral assembly. RNA viruses can exist as single-stranded (ssRNA) as well as the double-stranded (dsRNA) nucleic acid.

Q1. b) Discuss Hershey and Chase experiment with suitable diagram. (5)


Hershey and Chase Experiment

Alferd Hershey and Martha Chase conducted the second pivotal experiment on virus replication using bacteria in 1952. They worked with Escherichia coli-infecting bacteriophage T2. The bacteriophage T2 has a protein coat on the outside and DNA on the inside. E. coli cultures were grown on media containing radioactive S-35, sulphur in the sulphate form, by Hershey and Chase. Sulfur is found in the amino acids cysteine and methionine, both of which are found in the protein coat. Another pair of E.coli culture in media containing radioactive P-32, phosphorous in the form of phosphate. So, Hershey and Chase had one batch of E.coli containing radioactive S-35 sulphur and another set containing radioactive P-32 phosphorous. The bacteriophage T2 phages were infected separately into these bacterial cells with radioactive sulphur and radioactive phosphate. Radioactive sulphur atoms were integrated into the protein coats of these offspring phages in E. coli cultivated on medium with radioactive S-35. The DNA of these phages, on the other hand, was non-radioactive. P-32 was integrated into the DNA of progeny phages in E. coli cultivated on medium containing radioactive phosphorus (P-32).

The Hershey and Chase Experiment where phages were grown with radioactive S-35.


S-35 and P-32 bacteriophage T2 were inoculated into new nonradioactive E. coli cells, respectively. The infected culture was centrifuged to remove the viral coatings a few minutes after infection (see fig.b, above). Nonradioactive bacteria infected with P-32 (radioactive) bacteriophages T2 became radioactive, and much of the radioactivity was passed on to the next generation of bacteriophages T2. However, no radioactivity was identified in the infected cells of nonradioactive bacteria infected with bacteriophage T2 labelled with S-35 (above Fig.c).


Q2.a) Describe a bacterial cell wall and its adherents with proper diagram (5)



The bacterial cell wall is a strong, rigid, and flexible structure that shapes the germs you've already learned about. It's porous, which aids the movement of tiny chemicals into and out of the bacterial cell. In this section, you will learn about the construction and function of the bacterial cell wall, as well as the numerous types of adherences.


Q2. b) Describe transformation in bacteria with suitable diagram. (5)

Ans) Bacterial transformation is a process of horizontal gene transfer by which some bacteria take up foreign genetic material (naked DNA) from the environment.

Bacterial transformation is a process of horizontal gene transfer by which some bacteria take up foreign genetic material (naked DNA) from the environment.

1 DNA as the transforming principle was demonstrated by Avery et al in 1944.

2 The process of gene transfer by transformation does not require a living donor cell but only requires the presence of persistent DNA in the environment. The prerequisite for bacteria to undergo transformation is its ability to take up free, extracellular genetic material. Such bacteria are termed as competent cells.


The factors that regulate natural competence vary between various genera. Once the transforming factor (DNA) enters the cytoplasm, it may be degraded by nucleases if it is different from the bacterial DNA. If the exogenous genetic material is similar to bacterial DNA, it may integrate into the chromosome. Sometimes the exogenous genetic material may co-exist as a plasmid with chromosomal DNA.


Q3.a) ‘Algae can be found in diverse type of habitats’. Justify the statement.  (5)

Ans) Algae is found in different habitats as is explained below:


Algae in Diversified Habitat:

Algae comprise a group of chlorophyll containing thalloid plants and differ from fungi in the presence of photosynthetic pigment-chlorophyll and in their mode of nutrition. Algae are of universal occurrence, found in a variety of habitats such as freshwater. sea water, on snow, on rocks and on/or within the plant and animal bodies.


They may be classified into the following three groups:


1. Aquatic algae

The aquatic or hydrophilous algae are either free-floating (Chlamydomonas, Volvox, Spirogyra), attached on substratum by holdfast (Oedogonium, Ulothrix) or free-floating or in colonial form on the surface of water (water blooms or phytoplankton). Algae like Dictyosphaerium, Fragilaria, Cosmarium, Volvox, Asterionella and Golenkinia are commonly found in freshwater planktons. whereas Actinocyclus. Chaetoceros and Coscinodiscus are common in marine planktons. Many algae are found attached to rocks along the edges of lakes and seas and these forms are called phytobenthos, the phytoplankton or planktophytes may be free floating in early sieges of life called Tychopplanktophytes (Oedogonium. Cladophora, sargassum, Nostoc) or some of remain free-floating throughout their life and are called Euplanktophytes (Clamydomonads volvox, closterium.) Aquatic forms are found in fresh water or in saline water of the sea.


2. Terrestrial Algae

Such algae found in terrestrial, edaphic algae or edaphophytes or terrestrial algae habitats like soils, rocks, logs etc. the algal forms like Vaucheria, Botrydium, Fritschiella and Euglena are found on the surface of the soil known as saphophytes, or under the soil as blue - green algae (Nostoc, Anabaena, Voucheria, Oedogonium, Frischiella) Known as cryptophytes. A few algae are found on tree trunks and moist walls they absorb carbondioxyde and water from the atmosphere (Protococcus scytonema).

The algae growing in the desert soil may be typified as endedaphic (living in soil), epidaphic (living on the soil surface), hypolithic (growing on the lower surface of the stones on soil), chasmolithic (living in rock fissures) and endolithic algae (which are rock penetrating). The common terrestrial members are Oscillatoria sancta, Vaucheria geminata, Chlorella lichina, Euglena sp., Fritschiella sp. and Phormidium sp.


3. Algal species of unusual habitat

In addition of aquatic and terrestrial habitat some algae also occur in uncommon habitats as given below:

Benthic Algae

These attached to any substratum in the bottom of water bodies are called benthic algae or benthophytes may be fresh water (Chara, Nitella, Cladophora) or marine water living (Sargassum fucus)

Eqatic Algae

Found attahed to the substrata along the shores of freshwater bodies are called epactic algae or epaciphytes (Oedoonium Spirogyra, Rivularia).


Thermophilic algae

  1. Such algae living in hot springs at around 55eC or above (Oscillatoria brevis, Synechococcus elonganus, Heterohormogonium sp. Haplosiphon lignosum spp).

  2. They are able to survive such high temperatures possibly due to absence of well-organized nucleus.

  3. Most hot springs are alkaline so some phycologists believe that tolerance to high temperature may be associated with this factor.


Q3. b) Describe the different types of life cycles found in algae, illustrate each with suitable diagram. (5)

Ans) Life cycle of Algae

Sequential changes of the different pages through which an organism completes the life process, starting from zygote to the zygote of the next generation is called the life cycle.


There are four types of life cycle in algae such as:


1. Haplontic Life Cycle

Plants in this cycle are haploid. The Haplontic Life Cycle is a diphasic cycle and is considered the most primitive. The haplontic life cycle has two stages: gametophyte (haploid) and sporophyte (diploid). The gametangium of the gametophytic plant develops Haploid gametes. In the next stage of the life cycle, two haploid gametes are united to produce a zygote.

They are subsequently meiotically divided into haploid (n) zoospores, which mature into haploid plants. The gametophyte (haploid) stage. The monogenic or haplontic life cycle.


2. Diplontic Life Cycle

Plants in this cycle are diploid. Sex organs grow early in saprophytic plants. Then sex organs meiosis and produce gametes. This is the gametophytic stage. The gametes are then fertilised to form a zygote. Forming a saprophytic plant body.

3. Diplohaplontic Life Cycle

The diplohaplontic life cycle has separate haploid and diploid vegetative individuals. Chromosome number and function vary. The haploid gametophytic plant reproduces sexually, while the diploid sporophytic plant reproduces asexually. In this cycle, two vegetative individuals alternate due to sporogenic meiosis and gamete fusion.


4. Triphasic Life Cycle

In this type, there is a succession of three distinct generations. The triphasic life cycle is two types such as;


Haplobiontic Type

The gametophytic (haploid) phase in Haplobiontic Type is elaborate, dominating, and lasts longer than the sporophytic (diploid) phase. It is found in Rhodophyceae primitives like Batrachospermum and Nemalion. Batrachospermum's gametophytic plant body develops sex organs (spermatium) and female (egg) gametes. A zygote is formed by fusing two gametes.

The zygotes then meiosis to generate a carposporophyte, a haploid gametophyte. Once the carposporophyte has matured, it forms a haploid carpospore. Then carpospores germinate to form a new free-living gametophytic plant. These include haploid carposporophyte, haploid gametophyte, and diploid zygote.

Haplobiontic Algae Life Cycle


Diplobiontic Type

The triphasic character of Diplobiontic Type is indicated by one gametophytic and two sporophytic phases. Unlike the diplobiontic form, the sporophytic phase is more elabor­ate and long-lasting. Polysiphonia, a Rhodophyceae member, has this life cycle. Polysiphonia possesses two types of gametophytic plants, male and female, which bear spermatangium and carpogonium, respectively. The sperms and eggs come from spermatangium and carpogonium. The zygote is created when male and female gametes unite. The zygote (2n) develops into a diploid carposporophyte containing diploid carpospores.


These germinate to generate diploid tetrasporophytic plants. The tetrasporophytic plant generates a diploid tetrasporangia, which produces four tetraspores (n) through meiotic division. These four tetraspores produce two male and two female gametophytes. Diplobiontic Type has three phases: haplogametophyte, carposporophyte, and tetrasporophyte.


Q4.a) Compare the structure of mycelia of Penicillium and Agaricus. (5)

Ans) Ascomycetes are sac fungi. Aspergillus and Penicillium are two genera of ascomycetes. Aspergillus conidiophores are non-septate and unbranched stalks while Penicillium conidiophores are septate and branched brush-like structures. So, this is the key difference between Aspergillus and Penicillium.


Moreover, the colour of the Aspergillus species ranges from green, yellow, brown to black while Penicillium species are mostly blue in colour. Therefore, this too is a difference between Aspergillus and Penicillium.


Difference Between Aspergillus and Penicillium


Aspergillus: Any genus of ascomycetes fungi with branched, radiate sporophores

Penicillium: A blue mold commonly found on food and used to produce penicillin, an antibiotic


Color of the Mold

Aspergillus: Green to black

Penicillium: Blue



Aspergillus: A straight ending in a large vesicle 

Penicillium: Branched conidiophore



Aspergillus: Causes aspergillosis in lungs

Penicillium: Used in the production of antibiotics that are effective against Gram-positive bacteria



Aspergillus consists of an unseparated conidiophore, which is a large vesicle with conidiospores. But Penicillium consists of a brush-like, separated conidiophore. Aspergillus and Penicillium are two types of molds in the same family. The main difference between Aspergillus and Penicillium is the structure of the conidiophore.  


Q4. b) Discuss the role of Lichens as food, medicine, and dyes. (5)

Ans) Lichen is the sole flora available to animals in many difficult places like polar climates, cliffs, and deserts. Reindeer and caribou eat Cladonia rangiferina, also called reindeer moss. Sheep and land snails consume a lot of the fruticose lichens that grow on the ground. The lichen Lecanora is gathered and consumed in some areas, such as the Libyan desert. Umbilcaria foliosa is a foliose rock lichen that is used as a salad in Japan. Many of the lichens found in Iceland are eaten.


Other Uses of Lichens

Lichens' medical potential has long been recognised in folk medicine, and they are still commonly utilised today. Many lichens have antibacterial qualities, including Lobaria pulmonaria for lung disorders and Peltigera canina for hydrophobia. Usnic acid from Usnea is efficient against human infections such as fungi, bacteria, and viruses. Lichen-derived compounds can also be used to combat plant diseases such as tomato canker and tobacco mosaic virus.


Lichens were the source of coloured compounds used for dyeing fabrics before the invention of synthetic dyes. Lichens such as Roccella, Parmelia, Ochrolechia, and Evernia are used to extract colours such as orcin, which can be used to dye wool in shades of red, purple, and brown. Orcein, a lichen-derived stain for the nucleus in plant and animal cells, is employed in biological laboratories, while litmus, an acid-base indicator, is derived from the lichen Roccella.


Q5. Discuss the adaptive strategies developed by aqueous plants during the phase(s) of transition to land habitat. (10)

Ans) The transition of plants from aquatic environment to land is probably the most important and significant event in the history of our planet.


For proper adaptations, certain morphological changes in the life of plants were pre-requisite for land dwelling. These changes would be to meet the specific needs related to anchor; photosynthesis, transport of nutrients and water, gaseous exchange, prevention of desiccation, ensured fertilisation, care of embryo, and search of new ecological niches.


1. Anchor

Any plant on land needs to be anchored. Simple unicellular rhizoids in liverworts and hornworts and multicellular rhizoids in mosses are the most primitive but equally effective modes of substratum anchoring. A more evolved root system in vascular archegoniates might support the huge above ground sporophytes.


2. Water and Mineral Uptake

Early archegoniates were aquatic and drew water from the environment. Aquatic algae could also obtain minerals from the water. After moving to land, the plant will need a steady supply of water to replace the water lost through evaporation. Bryophytes, being small in size, had two advantages: they needed little water and could acquire it from nearby soil or thalli or axes. To compensate for water loss by evaporation from their exposed surface, bryophytes usually completed their life cycle during the wet season, when the relative humidity was high. Rhizoids in bryophytes probably only function in mineral uptake and anchoring. However, higher vascular archegoniates' roots serve three functions: anchorage, water intake, and mineral uptake.


3. Photosynthesis

Most aquatic algal ancestral cells/filaments were phototrophic. The chlorophyllous, photosynthesizing cells/tissue become specialised and strategically situated inside the aerial organs to receive maximal solar radiations, e.g., higher photosynthetic chambers of Marchantia, ‘leaves' (phyllids) of mosses, and mesophylls in leaves.


4. Transport

Transition to land habitat requires three strategies: transporting water, minerals, and photosynthetic products to all nonphotosynthetic components of the plant, including roots. It was discovered that hydroids and leptoids were fulfilling these activities in certain bryophytes. Vascular archegoniates have specialised xylem and phloem tissues. Root and shoot systems contain these tissues. Xylem transports water and minerals whereas phloem transports food.


5. Control of Evaporation and Gaseous Exchange

As the plant grows away from the earth (water supply), its surface becomes exposed to the atmosphere. Also, when the leafy shoots expand, the exposed surface area expands. Exposed surface water evaporates and transpires, reducing photosynthetic capacities.


6. Matrotrophy

In this case, plants moved to land habitat to protect and nourish the developing embryo. The gametophyte's photosynthetic products/stored food are delivered to the ‘embryo' via the archegonium's venter. The ‘transfer cell' properties of archegonium gametophytic tissue and sporophyte peripheral cells have been established. The gametophyte's "mother cells" nurture the archegoniate embryo. Maybe it's a parasite. This is known as matrotrophy. Morphologists believe matrotrophy is the most crucial event in plants' adaptation to land.


7. Siphonogamy

Male (and sometimes female) gametes of primordial aquatic algae are flagellated and motile. They approach the female gamete to fertilise. The non-motile female gamete, the egg cell, is limited to the archegonium's base. Many motile male gametes (antherozoid/spermatozoids) are released by antheridia. The spermatozoids swim to the archegonium's tip. The archegonium ensures fertilisation. Antherozoids must be produced in large quantities to assure fertilisation, as their ability to go to an archegonium depends on the presence of a film of water at the appropriate time and place. In gymnosperms, male gametophytes are pollen grains, which are non-motile reproductive units. The wind carries them to the ovules that contain the egg cell. Its tube-like extension carries and deposits male gametes near the egg cell for fertilisation. Siphonogamy is the transfer of male gametes to female gametes. Thus, this method of fertilising is not dependent on external water sources and allows plants to spread out over a large area of land.


8. Sterility of Sporophyte

Archegoniates create multicellular embryos by delaying meiosis and repeating mitotic divisions. The potential to diversify increases with sporophyte cell count. Distinguishing epidermis from stoma; chlorophyllous cells; hydroids and leptoids; foot; seta; capsule; or even organs such as roots; stem; leaves; sporophyll; and rhizome


The ability of a spore to deposit a highly specialised and resilient chemical sporopollenin may have enabled the transition to land habit. It is known to withstand extreme physical and chemical conditions. Fossil spores and pollen grains are well preserved, possibly due to sporopollenin on their outer wall.


Q6. Compare the characteristics of liverworts, hornworts and mosses in a tabular form with suitable diagrams (10)

Ans) Difference Between Liverworts and mosses

Listed below are some differences between liverworts and mosses:


Q7.Only through labelled diagram show:

Q7. a) Vertical transverse section of a thallus of Marchantia. (5×4=20)


(a-d): Internal structure of Marchantia: a) A part of thallus in three-dimensional view;

b) Vertical transverse section of a thallus (diagrammatic); c) The marked portion in

‘b’ enlarged to show the detailed structure of the thallus. Note the air pore;

d) An air pore seen from below (left-hand figure), it is surrounded by papillose

cells, air pore as seen from top (right hand figure).


Q7. b) L.S. capsule showing annulus and apophysis with stoma of Funaria.


(a - l): Funaria : a – c, f - h) L.s. of early stages of development of archegonium; d, e) T.s. of early stages of development: i, j) Longitudinal sections of upper; i) and lower; j) part of the archegonium; k) Young archegonium. l) Mature archegonium.

Q7. c) T.S. of a young root Pinus sp. after secondary growth has been established.



Pinus sp. Transverse section (T.S.) of a tetrarch root after secondary growth. The outer region is scaling off in plates. There is a resin duct opposite each of the four protoxylem element. The crushed protophloem is still visible, and outside it is cells rich in starch, and just beneath the scaling off layers are numerous resin cells.


Q7. d) T.S. of coralloid root of Cycas sp.



Cycas sp. normal root (a, b) and coralloid root (c, d). a) Outline diagram of a transverse section of a normal root. Note the diarch condition; b) A sector of the normal root enlarged to show the cellular details; c) Outline diagram of a transverse section of a coralloid root. Mark the position of the algal zone; d) A part of the algal zone magnified to show the radially elongated cells containing the alga (a-c, after Pant, 1973; d, after Wettstein, 1935).


Q8. Draw the labelled life cycle of a heterosporous pteridophyte. (5)



Q9. Discuss why is the seed of gymnosperms considered having remarkable combination of two generation. (5)

Ans) Gymnosperms are a modest part of the world's flora. Conifers are restricted to temperate zones where they produce extensive forest belts. Tall, perennial trees valued for their timber, resin, and pulp. We must now find and grow “elite” trees with desirable traits like higher production, disease and insect resistance. Testing and preserving wild germplasm is vital. Cycads and Ginkgo are two of the world's oldest plant families. Their native habitats are shrinking due to human pressures. If man does not save these “living fossils,” they will perish. This requires both in situ and ex situ measures.


Some gymnosperms, like Taxus, have showed promise as cancer cures. Other members of the group may become economically important in the future, making their preservation crucial.


Conifers are the world's tallest, oldest, and heaviest living things. With rare exceptions, these are tall woody plants that provide most of the world's lumber. Traditionally, much of the world's conifer lumber has been harvested by hand from wild strands of trees. The exploitation is so extensive that their natural population has dropped dramatically, especially in tropical and southern insular areas. Many wild species provide the most valuable timber, but little work has been done to replant them, and if any is done, it is with introduced fast growing species like Pinus. Now widespread conifer species are Pinus. Localized conifer populations are endangered, and mature trees are scarce.


IUCN has formed a dedicated conifer conservation group with its Secretariat in Edinburgh's Royal Botanic Gardens. Conifer conservation This can be done on a limited scale by seed banks and the creation of small genetic material selections under cultivated settings, sometimes species far from their natural environments. But certain taxa's slow development rates and long age cannot be matched in short culture periods. Thus, preserving full strands of unfelled wild trees is critical to preserving the future of these extremely valuable genetic resources.


Q10. Write notes on the following:


Q10. i) Economic importance of bacteria

Ans) Bacteria have widespread economic importance as they are used in various processes, as discussed below. The Economic Importance of Bacteria examples will help understand the significance of bacteria.


1. Dairy products

Quite a few genera of bacteria are used in food preparation, directly or indirectly. 

  1. Formation of Curd: Milk is converted into curd by bacterial action. The milk’s lactose is converted into lactic acid, which gives the characteristic sour taste of the curd. Lactic acid bacteria (LAB) like Lactobacillus are added to milk. Indian curd is prepared by inoculating milk with Lactobacillus acidophilus.

  2. Yoghurt preparation: It is produced by curdling milk with Streptococcus thermophilus and Lactobacillus bulgaricus.

  3. Cheese production starts with milk coagulated with lactic acid bacteria and the curd formed is filtered to separate the whey. The solid mass is then ripened with the growth of mould that develops flavour in it. Propionibacterium shermanii is used to make cheese.


Q10. ii) Ecological significance of mycorrhiza

Ans) Mycorrhiza is an important part of the ecosystem's nutrient cycling and protects the host plant from environmental stress. Plant mycorrhizal structure is a natural phenomenon in natural conditions, and arbuscular mycorrhiza (AM) association is the most prevalent mycorrhizal type. The amount and quality of plant production will be greatly improved if a well-formed mycorrhizal structure can be developed during the plant root system development phase. AM symbiosis is thought to reduce chemical fertiliser and pesticide use because of its effects on plant growth and health. As a result, the environmental impact of dangerous chemical substances will be reduced.


The following are the main effects of AM symbiosis: (1) improved rooting and plant establishment; (2) improved uptake of low mobile ions; (3) improved nutrient cycling; (4) increased plant tolerance to (biotic and abiotic) stress; (5) improved soil structure; and (6) increased plant community diversity. The ecological characteristics of arbuscular mycorrhiza fungi (AMF), their effects on host plants, and the ecological significance of AM biotechnology in agricultural systems were discussed in this research.


Q10. iii) Telome theory 

Ans) Telome hypothesis is based on the fossil record and synthesises the fundamental milestones in vascular plant evolution.


The ultimate terminal section of a dichotomising axis, or the point of the most distal dichotomy to the tip of a branch, is known as a "telome." Mesomes are the connecting axes between dichotomies. Telomes are divided into two groups based on their function: fertile telomes and sterile telomes. A fertile telome is one whose ultimate branch is terminated by a sporangium, whereas sterile telomes are those whose terminal branches are not terminated by sporangia. A syntelome or telome truss is formed when several telomes, whether fertile or sterile, are linked together by linking mesomes to produce a more complicated structure.


Q10. iv) Economic importance of pteriodphytes 

Ans) Vascular Cryptogams, also known as Pteridophytes, are seedless vascular plants that emerged after bryophytes. Pteridophytes are essential economically as well as being a lower plant.


Pteridophytes is also utilised as a pharmaceutical. In homoeopathy, a decoction of Lycopodium foliage is used to treat diarrhoea, bladder irritation, eczema, rheumatism, constipation, and liver inflammation. Equisetum's flavonoids and saponins have diuretic properties. Dryopteris, a fern, produces an antihelminthic medication. Marsilea sporocarps are a good source of starch and are eaten for their nutritional value. Externally, Osmunda cinnamomea is used to treat rheumatism, and orally, it is used to treat joint discomfort. The chemically active primary 'Marsiline,' isolated from Marsilea, has been proven to be highly effective against sedative and anti-convulsant agents.


Pteridophytes are employed as indicator plants as well. Equisetum's stems accumulate minerals, particularly gold. Asplenium adulterinum is a nickel indicator plant, while Actinopteris australis is a cobalt indicator.


Q10. v) Rhynia

Ans Rhynie plant, a rootless, leafless, spore-bearing plant preserved in the Rhynie Chert, a Devonian mineral deposit near Aberdeen, Scotland, dated to the early Devonian Period. Rhynia, for example, was around 18 cm tall and had water-conducting cells called tracheids in its stem, which were similar to those found in most living plants. Its aboveground stems were photosynthetic, branched equally several times, and generated elliptical sporangia at the tips of every branch, which were joined by underground runners. Aglaophyton, the most peculiar Rhynie plant, resembled Rhynia in most ways except for its tracheids, which were more like those of current mosses.


Other organisms from the same geologic time span are preserved in the Rhynie Chert, along with many taxa of plants. The fungus Palaeomyces, for example, could have been a parasite or a decomposer of the Rhynie flora. The Rhynie Chert also contains a range of arthropods that may have fed on the Rhynie plants' spores and tissues.

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