Bryophytes (General) Questions in English

(C) $Nostoc$ is a genus of cyanobacteria that is known to form symbiotic associations with various plants.
Specifically,$Nostoc$ colonies are frequently found living within the thallus of the bryophyte $Anthoceros$ as a space parasite or symbiont.
In this association,$Nostoc$ provides fixed nitrogen to the $Anthoceros$ plant,while the plant provides a protected environment for the cyanobacteria.

(B) . In $Bryophyta$,specialized vascular tissues like $xylem$ and $phloem$ are absent.
They are the first group of land plants that form embryos,hence they are classified as non-vascular embryophytes.

(D) The correct answer is $(d)$. The genus Dawsonia,found in New Zealand,is considered the largest bryophyte (moss),reaching a height of up to $60 \ cm$.

(C) Prof. $S.R. Kashyap$ is widely recognized as the "Father of Indian Bryology".
He made significant contributions to the study of liverworts and mosses in India, particularly in the Himalayan region.
His extensive research and documentation of the bryophyte flora of the Western Himalayas established the foundation for the field in India.

(C) In $Bryophyta$,the life cycle exhibits a heteromorphic alternation of generation.
This means that the sporophytic phase $(2n)$ and the gametophytic phase $(n)$ are morphologically and structurally distinct from each other.
The gametophyte is the dominant,independent,and photosynthetic phase,while the sporophyte is dependent on the gametophyte for nutrition and anchorage.
Therefore,the correct option is $C$.

(D) The $Archegonium$ is the female reproductive organ in bryophytes,pteridophytes,and some gymnosperms.
It consists of a swollen basal portion called the $Venter$ and a slender neck.
The $Venter$ contains the egg cell (oosphere) and a venter canal cell.

(B) The correct answer is $B$.
$1$. Bryophytes are non-vascular plants,meaning they lack specialized $xylem$ and $phloem$ tissues for the transport of water and nutrients.
$2$. They reproduce via spores and undergo an alternation of generations where the zygote develops into an embryo,which eventually grows into the sporophyte generation.
$3$. Unlike Pteridophytes,they lack vascular tissue,and unlike Gymnosperms,they do not produce seeds.

(C) The correct answer is $C$. Bryophytes are of great ecological importance.
$1$. They play a significant role in plant succession on bare rocks or soil,as they are often the pioneer species that colonize these areas.
$2$. They help in preventing soil erosion by forming dense mats on the soil surface,which reduces the impact of running water.
$3$. Some species,like $Sphagnum$,are used as peat,which has various uses,but their primary significance lies in their ecological role as pollution indicators and soil binders.

(D) In $Bryophyta$,the sporophyte is not free-living or photosynthetically independent.
Instead,the sporophyte is multicellular and remains attached to the photosynthetic gametophyte for its nutrition.
Therefore,option $D$ is not a characteristic feature of $Bryophyta$.

(A) The gametophytic generation is haploid $(n)$ and represents the dominant phase in the life cycle of bryophytes.
The gametophytic generation begins with the germination of a spore and ends with the production of gametes.
Gametes are the final products of the gametophytic generation,which fuse to form a diploid $(2n)$ zygote,marking the beginning of the sporophytic generation.
Therefore,the correct option is $A$.

(D) The correct answer is $(d)$.
$Sphagnum$,commonly known as bog moss,is a true moss belonging to the division Bryophyta.
Club moss refers to $Lycopodium$,which is a pteridophyte.
Reindeer moss is a lichen ($Cladonia$ $rangiferina$).
Irish moss is a red alga ($Chondrus$ $crispus$).

(C) The correct answer is $C$.
$1$. Brown algae $(Phaeophyceae)$ and Red algae $(Rhodophyceae)$ are predominantly marine and are commonly found along the sea-coast.
$2$. Mosses $(Bryophytes)$ require a moist and shady environment for their growth and reproduction. They are generally not adapted to the high salinity conditions found in marine environments.
$3$. Therefore,mosses are the least likely to be found along the sea-coast.

(B) The sporogonium of $Marchantia$ is differentiated into foot,seta,and capsule.
The capsule contains elaters $(2n)$.
Elaters are diploid,spindle-shaped,hygroscopic,elongated structures with $2$ spiral bands that aid in spore dispersal.

(B) In the life cycle of plants,the dominant phase is the one that is independent and photosynthetic.
In $Bryophyta$,the main plant body is a haploid gametophyte,which is independent and photosynthetic.
In contrast,in $Pteridophyta$,$Gymnosperms$,and $Angiosperms$,the dominant phase is the diploid sporophyte.

(C) Bryophytes are considered the first land-inhabiting plants,often referred to as the amphibians of the plant kingdom.
They are the most simple and primitive group of embryophytes.
They include approximately $840$ genera and $23,500$ species.

(D) $Sphagnum$ is of considerable economic importance.
$1$. It provides peat,which has long been used as fuel.
$2$. Because of its high water-holding capacity,it is used as packing material for the trans-shipment of living material (like plant roots) to prevent them from drying out.
$3$. It is also used in seed beds due to its excellent water retention properties.

(C) . The female sex organ in bryophytes is the archegonium. It is a flask-shaped structure that is distinguishable into a long neck and a globular swollen venter. Algae lack such specialized multicellular sex organs,whereas bryophytes possess them,which is a key evolutionary advancement.

(A) In bryophytes,the diploid $(2n)$ chromosome number occurs in the spore mother cell.
The plant body of a bryophyte is haploid $(n)$.
Spore mother cells are present within the spore sac (sporangium),which undergo meiosis (reduction division) to produce haploid $(n)$ spores.
Gametes,spores,and meiospores are all haploid $(n)$ structures.

(B) Gemmae are specialized vegetative reproductive structures found in certain $Bryophytes$,specifically in liverworts like $Marchantia$.
These are green,multicellular,asexual buds that develop in small receptacles called gemma cups located on the thalli.
When these gemmae detach from the parent plant,they germinate to form new individuals.

(A) The male sex organ in bryophytes is known as the antheridium,which is typically globular in shape.
It produces biflagellated male gametes known as antherozoids.
These two flagella are similar in structure,attached apically,and are of the whiplash type.

(A) The evidence for the aquatic origin of bryophytes is the presence of ciliated (flagellated) sperms (antherozoids).
In bryophytes,water is essential for fertilization because the antherozoids require a liquid medium to swim towards the archegonia to reach the egg.
This dependency on water for the process of fertilization is a primitive trait inherited from their aquatic ancestors.

(A) $Buxbaumia aphylla$ is a well-known example of a saprophytic bryophyte.
These plants are non-green (lacking chlorophyll) and derive their nutrition from decaying organic matter,such as rotten wood.

(C) In $Bryophytes$,the gametophyte is the dominant,independent,and photosynthetic phase of the life cycle.
The sporophyte is multicellular and remains attached to the gametophyte for its nutrition and protection.
Therefore,the sporophyte is partially or fully dependent on the gametophyte for its survival.

(B) The correct answer is $B$.
Liverworts are a group of bryophytes that thrive in moist, shady, and humid environments.
The Western Himalayas are known for their high humidity, cool temperatures, and diverse microhabitats, which provide an ideal environment for the growth and diversification of liverworts.
Due to this rich biodiversity of liverwort species, the Western Himalayas are referred to as "The Golden Mine of Liverworts".

(D) In $Bryophytes$,the main plant body is a gametophyte,which is independent and photosynthetic.
The sporophyte is not free-living; it is dependent on the gametophyte for its nutrition,either partially or wholly.
Therefore,the sporophyte phase is small and generally parasitic on the gametophyte.

(D) Bryophytes are characterized by the following features:
$1$. They possess a flask-shaped female sex organ called an archegonium and a globular male sex organ called an antheridium.
$2$. They contain chloroplasts,which make them photosynthetic and green in color.
$3$. Their plant body is typically thalloid (not differentiated into true roots,stems,or leaves) and attached to the substratum by unicellular or multicellular rhizoids.
Therefore,all the given statements are correct.

(C) The thallus of liverworts (a group of bryophytes) is dorsiventrally flattened,lobed,liver-like,prostrate,and exhibits dichotomous branching.
$Marchantia$ is a specific genus of liverwort that clearly shows this characteristic dichotomous branching pattern.

(D) Bryophytes are known as the amphibians of the plant kingdom because they require water for the completion of their life cycle. Specifically,the male gametes (antherozoids) are flagellated and motile. They require a film of water to swim from the antheridium to the archegonium to reach the egg for fertilization.

(C) In bryophytes,the main plant body is a gametophyte,which is independent and photosynthetic. The sporophyte is multicellular and dependent on the gametophyte for its nutrition. Therefore,the statement that the gametophyte is reduced and dependent is incorrect,as the gametophyte is the dominant,independent phase.

(D) The term $Bryophyta$ was coined by $Robert$ $Braun$ in $1864$.
He initially included algae,fungi,lichens,and mosses under this group.

(C) The female sex organ in bryophytes is called the archegonium.
It is flask-shaped,consisting of a tubular neck and a swollen base known as the venter.

(D) $Anthoceros$ is a bryophyte that exhibits a symbiotic relationship with the nitrogen-fixing blue-green alga,$Nostoc$.
These algae reside within the slime cavities of the $Anthoceros$ thallus,providing fixed nitrogen to the plant in exchange for shelter and carbohydrates.

(C) The archegonium in bryophytes is a flask-shaped female sex organ.
It consists of a long,slender neck and a swollen basal portion called the venter.
The venter contains a venter canal cell and a single large egg cell (oosphere).
Therefore,the venter is the part that encloses the egg cell.

(D) The life cycle of $Bryophyta$ shows alternation of generations between a haploid gametophyte and a diploid sporophyte.
In $Bryophyta$,the dominant,independent,and photosynthetic phase is the haploid gametophyte.
The sporophyte is multicellular and dependent on the gametophyte for its nutrition.
Therefore,the adult plant body of a bryophyte is the gametophyte.

(A) Parthenogenesis is a form of asexual reproduction where an organism develops from an unfertilized egg or somatic cell without the involvement of meiosis.
Since no reduction division $(meiosis)$ occurs during this process,the chromosome number remains unchanged.
Therefore,the number of chromosomes in the second generation will be the same as that of the parent plant.

(C) Elaters are diploid,spindle-shaped,hygroscopic,elongated structures found in the sporangia of certain liverworts (like Marchantia). They are sensitive to moisture changes and help in the dispersal of spores upon maturity by twisting and untwisting.

(B) In the plant kingdom,the size of the gametophyte shows a trend of reduction as evolution progresses.
Bryophytes like $Polytrichum$ (a moss) have a dominant,independent,and photosynthetic gametophyte.
Pteridophytes like $Nephrolepis$ have a small,independent,and multicellular gametophyte called a prothallus.
Gymnosperms like $Cycas$ have a highly reduced gametophyte that is dependent on the sporophyte.
Angiosperms have the most reduced gametophyte (pollen grain and embryo sac).
Therefore,among the given options,$Polytrichum$ (a bryophyte) possesses the largest and most complex gametophyte.

(A) In $Bryophyta$,the main plant body is a gametophyte $(n)$,which is independent and may be thalloid (e.g.,$Riccia$).
In contrast,in $Pteridophyta$,$Angiosperms$,and $Gymnosperms$,the main plant body is a sporophyte $(2n)$.

(C) $Sphagnum$,a moss,provides peat that has long been used as fuel.
Because of its high water-holding capacity,it is used as packing material for trans-shipment of living material.
It is also used as a substitute for cotton in surgical dressings due to its absorbent properties.

(C) The correct answer is $C$. In mosses,the stomata are considered primitive because they lack functional guard cells that regulate opening and closing. These structures are specifically found in the $Apophysis$ region of the moss capsule,which is the sterile basal part of the sporophyte.

(B) In mosses,the male sex organs are called antheridia. Interspersed among the antheridia are sterile,green,multicelled,club-shaped hairs known as paraphyses (singular: paraphysis). These structures provide protection and help in the retention of moisture around the reproductive organs.

(C) The correct answer is $C$.
Protonema is the juvenile phase of the moss life cycle.
It is a green,branched,frequently filamentous structure that develops directly from the germination of a haploid spore.
It represents the early stage of the gametophyte in mosses,which eventually gives rise to the leafy stage.

(D) The moss sporophyte is attached to the gametophyte and is dependent on it for water,minerals,and some organic nutrients. However,it often contains chlorophyll and can perform some photosynthesis. Therefore,it is considered semiparasitic.

(A) In $Funaria$,the spore dispersal occurs through a sensor mechanism. The capsule contains a peristome,which consists of hygroscopic teeth. These teeth respond to changes in humidity (moisture levels) and move to release spores gradually through the operculum,acting like a sensor.

(C) In mosses like $Funaria$,the life cycle includes a protonema stage. The spore germinates to produce a creeping,green,branched,and frequently filamentous stage called the protonema. The leafy stage (gametophore) develops from the secondary protonema as a lateral bud. This leafy gametophore bears the sex organs at its apex.

(A) In mosses,the sporophyte consists of a foot,seta,and capsule.
Inside the capsule,the sporogenous tissue differentiates into spore mother cells.
These spore mother cells undergo meiosis (reduction division) to produce haploid spores.
Therefore,the reduction division occurs within the capsule.

(B) The moss capsule is the sporophytic structure responsible for spore production.
It consists of parts like the $operculum$,$peristome$ teeth,$annulus$,and $theca$.
$Protonema$ is the filamentous,haploid gametophytic stage that develops after the germination of spores released from the capsule.
Therefore,$Protonema$ is not a part of the capsule itself.

(C) $Funaria$ is a moss belonging to the class $Bryopsida$.
In mosses,the anchorage and absorption of water and minerals are performed by structures called rhizoids.
These rhizoids are multicellular and branched,which distinguishes them from the unicellular rhizoids found in liverworts.
Therefore,the correct option is $C$.