Bryophytes (General) Questions in English

(D) $Funaria$ is a moss belonging to the class Bryopsida.
- $a.$ Protonema: It is the juvenile stage in the life cycle of mosses,which develops from a spore.
- $c.$ Gametophore: The leafy stage of the moss that bears sex organs.
- $f.$ Haplodiplontic: Bryophytes exhibit a haplodiplontic life cycle where both haploid and diploid phases are multicellular.
- $h.$ Fragmentation: It is a common method of vegetative reproduction in mosses like $Funaria$.
- $b.$ Prothallus is characteristic of Pteridophytes.
- $d.$ Prostate thallus body is characteristic of Liverworts (e.g.,$Marchantia$).
- $e.$ $NCC$ (Neck Canal Cells) are present in the archegonium,not the antheridium.
- $g.$ True plant organs (roots,stems,leaves) are absent in the sporophyte of Bryophytes.
Therefore,the correct features are $a, c, f, h$.

(A) $Funaria$ is a bryophyte where the main plant body is haploid $(n)$.
Rhizoids are part of the gametophyte,so they are haploid $(n = 20)$.
Calyptra is derived from the venter of the archegonium,which is part of the gametophyte,so it is haploid $(n = 20)$.
Theca and foot are parts of the sporophyte,which is diploid $(2n)$.
Therefore,theca $(2n = 40)$ and foot $(2n = 40)$.
Thus,the number of chromosomes in calyptra,theca,and foot are $20, 40, 40$ respectively.

(D) In the given figure,plant '$A$' represents a male thallus of $Marchantia$. This is identified by the presence of antheridiophore,which has a disc-shaped head.
Plant '$B$' represents $Sphagnum$,a moss,which is characterized by its branched,leafy gametophyte structure.

(C) In $Funaria$ (a moss),the archegonium secretes sucrose at the tip of the neck to attract the male gametes (antherozoids). This movement of male gametes towards the chemical stimulus (sucrose) is known as chemotactic movement,not chemotropic movement. Chemotropism refers to the growth of a plant part in response to a chemical stimulus,whereas chemotaxis refers to the movement of a whole organism or cell (like a motile gamete) in response to a chemical stimulus. Therefore,the Assertion is correct,but the Reason is incorrect because it uses the wrong terminology.

(A) The life cycle of a moss consists of two stages in the gametophyte generation: the protonema stage and the leafy stage.
The first stage is the protonema stage,which develops directly from a spore.
The second stage is the leafy stage,which develops from the secondary protonema as a lateral bud.
This leafy stage consists of upright,slender axes bearing spirally arranged leaves.
This stage bears the sex organs,which are responsible for sexual reproduction.
Therefore,both the Assertion and the Reason are correct.

(B) $Marchantia$ is a dioecious plant,meaning the male and female sex organs are borne on separate thalli.
Antheridiophore is the specialized stalk-like structure that bears the antheridia (male sex organs).
Since antheridia produce male gametes,the antheridiophore is produced by the male thallus.
Therefore,the correct option is $B$.

(D) The image shows a male thallus of Marchantia,which is a liverwort.
$1$. The male thallus produces male gametes (antherozoids) within the antheridia located on the antheridiophore.
$2$. It forms specialized sexual branches known as antheridiophores,which bear the antheridia.
$3$. Since both options $(a)$ and $(b)$ are correct,the most appropriate choice is $(d)$.

(C) Gemmae are specialized asexual reproductive structures found in liverworts,such as $Marchantia$.
They are green,multicellular,asexual buds that develop in small receptacles called gemma cups located on the thalli.
When detached from the parent plant,these gemmae germinate to form new individuals.
Therefore,the correct option is $C$.

(B) Mosses and liverworts belong to the group $Bryophytes$.
$Bryophytes$ are non-vascular land plants that include mosses,liverworts,and hornworts.
They are often called the amphibians of the plant kingdom because they require water for fertilization.
Therefore,the correct option is $B$.

(D) $Bryophytes$ are known as the amphibians of the plant kingdom because they can live in soil but are dependent on water for sexual reproduction.
They require water for the movement of antherozoids to the archegonium for fertilization.
They typically grow in damp,humid,and shaded localities.
Therefore,all the given statements are correct.

(B) The given image represents the life cycle stage of a moss,specifically $Funaria$.
It shows the gametophyte (main plant body) and the sporophyte (capsule,seta,and foot).
The presence of a distinct capsule,seta,and leafy gametophyte with rhizoids is characteristic of $Funaria$.

(D) $Sphagnum$ (also known as peat moss) belongs to the division Bryophyta.
In bryophytes,the dominant phase is the gametophyte.
$Sphagnum$ is used as fuel and for trans-shipment of living material because of its water-holding capacity,forming peat.
$Sphagnum$ is monoecious,meaning both male and female sex organs are present on the same plant body.
Therefore,the statement '$Sphagnum$ is a monoecious plant' is correct,and the statement '$Sphagnum$ is a dioecious (unisexual) plant' would be incorrect. Since option $D$ states it is unisexual (eklingi),it is the incorrect statement.

(B) In $Bryophytes$,the main plant body is a haploid gametophyte.
The sporophyte is multicellular and diploid $(2n)$,but it is not free-living; it remains attached to the photosynthetic gametophyte for nutrition.
The sporophyte consists of a foot,seta,and capsule.
Inside the capsule,some specialized cells called spore mother cells undergo meiosis to produce haploid spores.
It is incorrect to state that all cells of the sporophyte undergo meiosis; only the spore mother cells do so.
Therefore,option $B$ is the incorrect statement.

(B) Sphagnum is a genus of approximately $380$ accepted species of mosses,commonly known as peat moss.
It is used as fuel because it forms peat,which is a brown,soil-like material characteristic of boggy,acid ground,consisting of partly decomposed vegetable matter.
Peat has been used as a source of fuel for centuries in many parts of the world.
Therefore,the correct option is $B$.

(D) Mosses (Bryophytes) play a significant role in the ecosystem:
$1$. They provide food for herbaceous mammals,birds,and other animals.
$2$. They form dense mats on the soil,which reduces the impact of falling rain and prevents soil erosion.
$3$. Along with lichens,they are the first organisms to colonize rocks and contribute to the decomposition of rocks,making the substrate suitable for the growth of higher plants.

(D) Liverworts usually grow in moist,shady habitats. Their habitat includes banks of streams,marshy ground,damp soil,bark of trees,and deep in the woods. Therefore,all the given options are correct.

(D) Gemmae are specialized asexual reproductive structures found in liverworts (e.g.,$Marchantia$).
$1$. They are green,multicellular,and asexual buds.
$2$. They develop in small receptacles called gemma cups located on the thalli.
$3$. When gemmae become detached from the parent body,they germinate to form new individuals.
Therefore,all the given statements are correct.

(A) In liverworts,the plant body is a gametophyte,which is haploid $(n)$.
This gametophyte represents the dominant,independent,and photosynthetic phase of the life cycle.
The sporophyte $(2n)$ is dependent on the gametophyte for its nutrition and is relatively short-lived.
Therefore,the dominant phase is haploid $(n)$.

(C) The life cycle of mosses (Bryopsida) consists of two distinct stages in the gametophyte generation:
$1$. The protonema stage: This is the juvenile stage that develops directly from a spore. It is a creeping,green,branched,and frequently filamentous structure.
$2$. The leafy stage: This stage develops from the secondary protonema as a lateral bud. It consists of upright,slender axes bearing spirally arranged leaves.
Both these stages are part of the gametophyte generation of mosses.

(A) In mosses (Bryophytes),the life cycle includes two stages in the gametophyte generation.
$1$. The first stage is the protonema stage,which develops directly from a haploid spore.
$2$. The second stage is the leafy stage,which develops from the secondary protonema as a lateral bud.
Therefore,the protonema stage develops from a haploid spore,and the leafy stage develops from the secondary protonema.

(A) $Marchantia$ is a genus of liverworts belonging to the group Bryophyta.
In $Marchantia$,the male and female sex organs are produced on separate thalli (plants).
Therefore,$Marchantia$ is dioecious (unisexual).
Since it is dioecious,it cannot be monoecious or bisexual.
Thus,the correct option is $A$.

(D) Bryophytes are divided into two main groups: Liverworts and Mosses.
$1$. $Marchantia$ is a classic example of a liverwort.
$2$. $Sphagnum$,$Funaria$,and $Polytrichum$ are examples of mosses.
Therefore,the correct classification is:
Mosses: $I$ $(Sphagnum)$,$II$ $(Funaria)$,$IV$ $(Polytrichum)$
Liverworts: $III$ $(Marchantia)$
Thus,the correct option is $D$.

(A) In bryophytes,the main plant body is haploid $(n)$.
It produces gametes by the process of mitosis.
The sex organs in bryophytes are multicellular.
The male sex organ is called antheridium and the female sex organ is called archegonium.
Since the plant body is already haploid,the production of gametes occurs through mitotic division.

(D) The provided figure shows the male and female thalli of the liverwort $Marchantia$.
In $Marchantia$,the male and female sex organs are produced on separate thalli,which means the plant is dioecious.
The left part of the figure shows the female thallus with an archegoniophore,and the right part shows the male thallus with an antheridiophore.
Therefore,the correct option is $D$.

(B) The life cycle of a moss consists of a dominant gametophyte phase which includes two stages.
The first stage is the protonema stage,which develops directly from a haploid spore.
These spores are produced within the capsule of the sporophyte generation.
Since the protonema is the direct product of spore germination,the Reason $R$ correctly explains the Assertion $A$.

(C) The life cycle of bryophytes follows these steps:
$1$. The gametophyte attaches to the substratum $(B)$.
$2$. Antherozoids are released into the water to reach the egg $(E)$.
$3$. Fusion of antherozoid with the egg occurs to form a zygote $(A)$.
$4$. The zygote develops into a sporophyte $(D)$.
$5$. The sporophyte undergoes reduction division (meiosis) to produce haploid spores $(C)$.
Therefore,the correct sequence is $B, E, A, D, C$.

(B) Gemmae are specialized green,multicellular,asexual buds that develop in small receptacles called gemma cups located on the thalli of certain liverworts (e.g.,$Marchantia$).
When these gemmae detach from the parent plant body,they germinate to form new individuals.
Therefore,gemmae are primarily involved in asexual reproduction (vegetative propagation) in bryophytes.

(A) Statement-$I$ is correct: Liverworts (e.g.,Marchantia) can be monoecious (same thallus) or dioecious (different thalli).
Statement-$II$ is correct: In bryophytes,the sporophyte is multicellular and differentiated into three parts: foot,seta,and capsule. Note: The original statement incorrectly used 'gametophyte' instead of 'sporophyte',which is a common point of confusion; however,in the context of biological classification,the sporophyte is indeed the structure differentiated into these parts.

(C) The life cycle of mosses (class Bryopsida) includes a distinct juvenile stage known as the protonema.
$1$. The spores germinate to produce a creeping,green,branched,and frequently filamentous stage called the protonema.
$2$. The protonema develops from the spore and eventually gives rise to the leafy gametophyte stage.
$3$. Liverworts and hornworts do not produce a protonema stage; instead,they typically develop a thalloid structure directly from the spore.

(C) Let us analyze each statement:
$(i)$ Incorrect: The plant body of bryophytes is more differentiated than that of algae (thalloid structure with root-like,leaf-like,and stem-like structures).
$(ii)$ Correct: The main plant body of bryophytes is haploid (gametophyte).
$(iii)$ Incorrect: Sex organs in bryophytes are multicellular,not unicellular.
$(iv)$ Correct: Zygotes in bryophytes do not undergo reduction division immediately; they produce a multicellular sporophyte.
$(v)$ Incorrect: Bryophytes depend on water for sexual reproduction (fertilization),not insects.
Thus,only statements $(ii)$ and $(iv)$ are correct. The total number of correct statements is $2$.

(D) Bryophytes are land-dwelling plants that exhibit several evolutionary advancements over algae.
$1$. Both algae and bryophytes contain chlorophyll '$a$' and '$b$',so this is not a distinguishing feature.
$2$. Prothallus is a characteristic structure found in Pteridophytes,not Bryophytes.
$3$. Vascular tissues (xylem and phloem) are absent in both algae and bryophytes.
$4$. Bryophytes possess multicellular sex organs,specifically the female sex organ called the archegonium,which is protected by a sterile jacket. Algae typically have unicellular sex organs (or if multicellular,they lack a sterile jacket layer). Therefore,the presence of archegonia is a key feature that distinguishes bryophytes from algae.

(C) The provided figure shows a plant with distinct branches labeled as 'Antheridial branch' and 'Archegonial branch'.
This morphology is characteristic of the moss $Sphagnum$.
$Sphagnum$ is a genus of mosses belonging to the division Bryophyta.
It is known for its ability to hold large amounts of water and is often used in the packaging of living material for transport.

(A) Statement-$I$ is correct: Bryophytes,especially mosses,are pioneer species in plant succession on bare rocks. They secrete acids to dissolve rocks,helping in the formation of soil,which allows higher plants to grow.
Statement-$II$ is correct: Peat moss (Sphagnum) has a high water-holding capacity. Due to this property,it is widely used as a packing material for the trans-shipment of living plant materials to keep them moist during transit.
Therefore,both statements are correct.

(A) The life cycle of a moss (like $Funaria$) follows this sequence:
$1.$ The cycle begins with the dispersal of spores $(II)$.
$2.$ These spores germinate to form the protonema stage $(III)$.
$3.$ The protonema develops into the leafy stage $(IV)$.
$4.$ The leafy stage produces gametes,which undergo fertilization $(I)$ to form a zygote,eventually leading back to the sporophyte and spore production.
Therefore,the correct sequence is $(II) \rightarrow (III) \rightarrow (IV) \rightarrow (I)$.

(A) Bryophytes are non-vascular land plants that include mosses,liverworts,and hornworts.
In Bryophytes,the male sex organ is called the antheridium,which produces biflagellate antherozoids (male gametes).
These antherozoids are motile and possess $2$ flagella,which help them swim through a film of water to reach the female sex organ,the archegonium.
Therefore,the correct answer is $2$ flagella.

(C) In $Funaria$ (a moss),the plant body is a gametophyte which is independent.
The sporophyte is dependent on the gametophyte for nutrition.
The sporophyte of $Funaria$ is structurally differentiated into three distinct parts: $foot$,$seta$,and $capsule$.
Therefore,option $C$ is the correct description.

(A) Statement $I$ is false because gemmae are green,multicellular,asexual buds,not sexual buds.
Statement $II$ is true because in mosses,the spore germinates to form a filamentous,creeping,green,branched,and frequently filamentous stage called the protonema.
Therefore,Statement $I$ is false and Statement $II$ is true.

(C) $Marchantia$ is considered a heterothallic plant because it is dioecious.
In $Marchantia$,the male and female reproductive structures (antheridiophore and archegoniophore) are borne on separate individual thalli.
Therefore,the plant body is unisexual,which is referred to as dioecious or heterothallic.

(D) $Riccia$,a liverwort within the $Bryophyta$,exhibits a dominant gametophyte phase in its life cycle.
In bryophytes,the gametophyte is the main stage,whereas the sporophyte is smaller and dependent on the gametophyte for nutrition.

(B) thallus-like plant body,lack of vascular tissues and autotrophic nutrition.
Bryophytes resemble algae in their thallus-like plant body,lack of vascular tissues,and autotrophic nutrition.
Both groups have simple,non-differentiated structures and rely on photosynthesis for nutrition.
Neither group possesses the specialized vascular tissues ($xylem$ and $phloem$) found in higher plants for transporting water and nutrients.

(C) The correct answer is $C$.
Bryophytes are known as non-vascular plants because they lack specialized vascular tissues,namely $Xylem$ and $Phloem$,which are responsible for the conduction of water and nutrients in higher plants.
$A$,$B$,and $D$ are characteristic features of bryophytes: they possess filamentous rhizoids for attachment,have a dominant gametophytic generation,and are often referred to as the amphibians of the plant kingdom due to their requirement for water for fertilization.