MARCHANTIA
Marchantia:
M. polymorpha
M. himalayansis these two spp. are commonly found in Nepal.
Distribution: Foot hills and the upper hills, cold countries, terai, moist, near the tap etc., appear during the rainy season, winter season.
Reproduction:
1. Vegetative reproduction:
a) By the death and decay of older part of the thallus.
b) By the production of adventitious buds
c) By the formation of Gammae.
2. Sexual reproduction:
a) Plant body is gametophytic usually reproduce sexually to produce the gametes having haploid no. chromosome.
b) Plant body is diocieous. Male thalli usually produce antheridiospore and female thalli produce the archegoniospore.
Systematic position:
Kingdom: plantae
Division:Bryophyta
Class: Hepaticopsida
Order: Marchantiales
Family: Marchantiacea
Genus: Marchantia
Morphology:
The plant body of marchantia is of gametophyte which is called a thallus. The mature thallus may attain the length of 1-10cm. it is a dark green in color and possess the prominent midrib. The midrib is marked by the shallow groove in the dorsal surface and shows the rosette type. Along the midrib, special cup like structures called gemma cups is present.
The ventral surface of the thallus bears two or more rows of violet, multicellular plate likes scales on the either side of the midrib. Scales are of two types: Ligulate and appendiculate.
The ligulate scales are small and have no appendages. Scales gives the protection to the growing point.
The ventral surface of the thallus also bears numerous rhizoids. They are pale brown, unicellular and branched. The rhizoid are of two types; smooth walled and tuberculated walled rhizoid. In the smooth walled rhizoid contain the smooth wall in the inner wall and in tuberculated rhizoids the inner wall possesses the peg like structure. They help in plant fixation and absorption of water and minerals.
In the reproductive stages thalli bears small upright, stalked structure called antheridiophores and archegoniophores. This bears male sex organ and female sex organ respectively.
Internal structure of the thallus:
A v.s. of the thallus shows the two distinct regions, the upper photosynthetic and storage region. The upper epidermis is single layered of thin walled cells. It is interrupted by several air pores. Air pores are barrel shaped consisting of 4-5 superimposed cells having both an upper and lower opening. The air pores are helps to exchange the gaseous during the respiration and photosynthesis the photosynthesis region consist of large no. of air chambers surrounded by the single celled thick 4-8 cells high septa.
The storage region consists of compactly arranged thin walled parenchymatous cells. Some cells may have single oil body or filled by the mucilage.
The lowermost layer of the storage region is lower epidermis. Rhizoids and scales are borne form certain cells of lower epidermis.
Sexual reproduction:
The sexual reproduction of the marchantia is oogamous type. Marchantia plants are dioecious , i.e. male and female sex organ develop in separate thalli. The male sex organ is the antheridia and female sex organ are called archegonia. The sex organ of marchatia is borne on special erect and stalked branches called the gametophores.
The gametophore bearing the antheridia is called antheriaophore or stalk of Male receptacle whereas the gametophore bearing archegonia is called archegoniophore or stalk of female receptacle.
Antheriodiophore:
Antheridiophore has an erect stalk which is about 2-3 cm in length. The top of antheridiophore is a flattened, slightly convex; eight lobed pelate discs each lobe of the disc has a growing point at its tip and this represent the apex of branch. On each lobe of the pellate disc, 10-12 antheridia develop in acropetl succession is the oldest being near the center and the youngest towards the tips of lobe. The ventral surface of stalk of antherodiosphore bears the scale and the rhizoids along the two grooves. The internal structure of antheridiospore is similar to that of the thallus. The antheridial chamber open outside by the pores called ostioles.
Structure of mature antheridium:
The mature antheridium is club shape structure and consists of a short multicellular and rounded or ovoid antheridium proper. The antheridium proper has a single jacket. The jacket layer encloses the single androcytes. The androcytes gets metamorphosed into motile biflagellated antherozoids or male gametes.
Dehiscence of the antheridium:
The mature antheridium dehiscence in the presence of water. When the water enter into the antheridial chamberthrough the outside, the antheridium become swell up. Some of the terminal cells the wall on coming in contact with water disintegrated. Thus the antheridium raptureand the mass of the antherozoid emerge out. The antherozoids are sets free from the mass and swim in water. Each antherozoid is long slightly coiled rod shaped st. with two flagella attach to the anterior end. The antherozoids swims in water present in the grooves of receptacles with the help of flagella.
Archegoniospore:
The archegoniospore consists of slender stalk and female receptacle. The stalks of mature archegoniosphore are comparatively longer and stouter then the antheridiospphore. The stalk is about 5-7cm in long and each surmounted by the lobe disc called the female receptacle. The disc is eight lobed with nine umbrellaslike rays dropping down.
All the archegonia are covered by the two-lipped membrane known as perichaetium or involucre. A cup shaped outgrowth that surround the archegonium called perigynium, give the protection to the archegonium.
Structure of the mature archegonium:
The mature archegonium is flask shaped structure developed on short stalk. It has swollen venter and long neck. The neck consists of the six vertical rows of jacket cells. The apical parts of neck consistof four covered cells or lid cells. A single layer of jackets surrounds the venter. The venter has one egg and one venter canal cell. The fully mature, the neck canal cell and venter canal cell disorganize and to form the mucilage mass. Which absorb the moisture and swells. The swelling exerts the pressure on lid cells so that they separate apart and the passage down to the egg is developed.
Fertilization:
It takes place in presence of water. The mucilage with the malic acids starts oozing through the mouth and that attract the antherozoids. The movement of the antherozoid in response of chemical is called chemotaxis. During the fertilization the antherozoids moving into water with female receptacle. Then a no. Of antherozoids enter the archegonium, but only one of them fuses with the egg to form the diploid zygote. The zygote developed the wall around itself and called the oospore. The fertilized egg or oospores represent the first stage of sporophytic generation.
Sporophyte:
After the fertilization the archegonial cells shrivels. The wall of venter gives the 1-4 layered investment called calyptra which is of the gametophytic origin. In addition, perigynium also grows rapidly and covers the calyptra. The third covering called the involucre or perichetium is already present around the archegonia of each lobe. Thus the mature sporophyte is enveloped by three distinct protective covering; thecalyptra, the perigynium, the perichaetium. These three covering layer protect young sporogonium from desiccation. The mature sporogonium of marchantia is completely parasite on gametophyte because of the lack of chloroplast; ventral position and the covering layer avoid the light penetration. It is differentiated into foot, seta and capsule:
1. Foot: it is made up of parenchymatous cells, which are situated towards the base of archegonium .It helps in absortion of food material from the gametophyte for developing sporophyte.
2. Seta: the seta is short stalked, junction of connecting link between the foot and the capsule. It helps in the dispersal of spores.
3. Capsule: it is situated towards the neck of archegonium. It has single jacket layer of cell.
Spores and germination of spores:
When the spores fall on the suitable condition they germinated. The swell by the absorption of water. The exine ruptures and intine produce the small germ tube. The filament like structure divided and redivided to form a multicellular structure and finally gets changed into dichotomously branched thallus of marchntia.
Alternation of generation:
The life cycle of marchantia shows the distict alternation of generation. The lifecycle is completed only when the plant passes through the both the stages. The dominant phase is haploid gametophytic phase. The gametophyte reproduces sexually by male and female gametes and the result in the formation of sporophyte. The sporophyte reproduces asexually by the formation of spores. These spores give rise to the gametophyte. Themarchantia plant is a gametophyte which develops from haploid sporo. The plant body consists of dorsoventrally differentiated thallus. The antheridia produce the female gametes or egg. The antherozoids swim in the water and reach to the egg of an archegonium. Out of them only one fuses with egg together to form a diploid zygote. The diploid zygote represent of first stage of sporophyteic generation. The diploid zygote develops into complicating and elaborated structure the sporogonium or sporophyte. The sporogenous cell inside the sporophyte divided by meiosis to form a tetrad of haploid. This method of spore formation involving the meiosis is an asexual reproduction. The spores gametophytic stage. Each sporegerminates and forms a haploid gametophytic thallus of marchantia.These two generation regularly alternate to each other. This is known as alternation of generation.
Class: Musci
1. Small leafy plant, rhizoid axis leaves are present.
2. Rhizoids are only one type.
3. Presence of colmella (sterile structure).
Moss: Funaria, polytrichum
Distribution: Worldwide in distribution, cold region, moist wall, rainy season and are valvate like, dry-winter season.
Structure:
Simple leafy plant 1-more cm in the length. Green in color, root like rhizoids, unicellular, branched, and only one type and helps in fixation, absorption of water mineral, stout and cylindrical stem leaves are small, membranous green with single rib, spiral manner.
Reproduction:
Sexual reproduction:
It takes place by the formation of male and female gamete. The male and female gamete. The male and female female reproductive organ are antheridia and archegonia which lies in the association with sterile hair like St. called the paraphysis. The male and female reproductive organ are developed at the different branches of same plant,i.e . monoecious. The male branch has diversed leaves consisting group of antheridia at its apex which are usually arranged to yellow in color. The female branch has covered leaves usually produce the capsule as sporogonium.
Antheridia of the male branch are club and covered by the jacket like st. they encloses the androcytes, where the spermatozoids are formed which comes out after the brusting of antheridia. Each antherozoids are coiled and biflagellated.
Similarly archegonia of female branch are flask shape having narrow elongated neck with a row of neck canal cell and swollen venter. Inside the enter an oval ovum is formed. At the time of fertilization , the N.C.C degenerate to formed mucilaginous mass, which produce the a cane sugar that attract the antherozoid, and fuses with egg to form diploid zygote. The zygote soon develop a covering wall and called oospore. Thus the end of gametophytic and beguning of sporophytic phase . The oospore germinate to give rise to sporophyte or sporogonium. The sporogonium consist of 3 main part :
1. Foot: Itremain buried inside the archegonium nad absorb the food material for developing sporophyte.
2. Seta: it acts as stalk that helps in transportation of food as well as it helps in dehiscence of capsule.
3. Capsule:the capsule is pear shaped structure covered by the calyptra. It is the apical region consist of cap like uperculim with teeth like st. called the peristome, attach to the annukus. The peristome is hydrophobic in nature.
FEMALE CAPSULE
The main body of capsule supported by a solid base called the apophysis, consisting of conducting cells. The body of the capsule is covered by a single layer called the epidermis; they form a small gap called the stroma which helps in ex-change of gaseous. It consists of solid sterile tissue called columella, surrounded by the spore sac wall attach to the air chamber with trabaculee. Each spore sac bears a spore mother cell, which undergoes the meiosis and result in the formation of spores, these spore dispersed in dry season and when it gets a favourable condition it germinates. Each spore germinates to form the free filamentous st. called the protonema, which produce numerous bud called protonemal buds. These buds give to new gametophyte.
Alternation of generation:
In the life cycle of it is clearly seen that there are two phases. The gametophytic phase and sporophytic phase, or germination of oospore represents the sporophytic phaseswhereas gametophytic phase is the formation of gametophyte. These two phase alter to each other. That is called as alternation of generation.
Gametophytic phase is dominated over the sporophytic phase and gametophytic phase last for long period of time and is independed.
Pteridophyte:
General character:
1. They are non-floweringplant reproduce by the formation of spores.
2. They are vascular cryptogams, due to the presence of xylem an d phloem.
3. They are terrestrial in habitat some are aquatic and epiphytic.
4. They are generally herbs and few of them are shrub.
5. The plant is sporophytic which consists of roots stems and leavesand vegetative cells are diploid, they reproduce asexually by the formation of homospore and heterospore.
6. They are recognized as the oldest group of the showing the origin from the Silurian period of geological era.
Antheriodiophore:
Antheridiophore has an erect stalk which is about 2-3 cm in length. The top of antheridiophore is a flattened, slightly convex; eight lobed pelate discs each lobe of the disc has a growing point at its tip and this represent the apex of branch. On each lobe of the pellate disc, 10-12 antheridia develop in acropetl succession is the oldest being near the center and the youngest towards the tips of lobe. The ventral surface of stalk of antherodiosphore bears the scale and the rhizoids along the two grooves. The internal structure of antheridiospore is similar to that of the thallus. The antheridial chamber open outside by the pores called ostioles.
Structure of mature antheridium:
The mature antheridium is club shape structure and consists of a short multicellular and rounded or ovoid antheridium proper. The antheridium proper has a single jacket. The jacket layer encloses the single androcytes. The androcytes gets metamorphosed into motile biflagellated antherozoids or male gametes.
Dehiscence of the antheridium:
The mature antheridium dehiscence in the presence of water. When the water enter into the antheridial chamberthrough the outside, the antheridium become swell up. Some of the terminal cells the wall on coming in contact with water disintegrated. Thus the antheridium raptureand the mass of the antherozoid emerge out. The antherozoids are sets free from the mass and swim in water. Each antherozoid is long slightly coiled rod shaped st. with two flagella attach to the anterior end. The antherozoids swims in water present in the grooves of receptacles with the help of flagella.
Archegoniospore:
The archegoniospore consists of slender stalk and female receptacle. The stalks of mature archegoniosphore are comparatively longer and stouter then the antheridiospphore. The stalk is about 5-7cm in long and each surmounted by the lobe disc called the female receptacle. The disc is eight lobed with nine umbrellaslike rays dropping down.
All the archegonia are covered by the two-lipped membrane known as perichaetium or involucre. A cup shaped outgrowth that surround the archegonium called perigynium, give the protection to the archegonium.
Structure of the mature archegonium:
The mature archegonium is flask shaped structure developed on short stalk. It has swollen venter and long neck. The neck consists of the six vertical rows of jacket cells. The apical parts of neck consistof four covered cells or lid cells. A single layer of jackets surrounds the venter. The venter has one egg and one venter canal cell. The fully mature, the neck canal cell and venter canal cell disorganize and to form the mucilage mass. Which absorb the moisture and swells. The swelling exerts the pressure on lid cells so that they separate apart and the passage down to the egg is developed.
Fertilization:
It takes place in presence of water. The mucilage with the malic acids starts oozing through the mouth and that attract the antherozoids. The movement of the antherozoid in response of chemical is called chemotaxis. During the fertilization the antherozoids moving into water with female receptacle. Then a no. Of antherozoids enter the archegonium, but only one of them fuses with the egg to form the diploid zygote. The zygote developed the wall around itself and called the oospore. The fertilized egg or oospores represent the first stage of sporophytic generation.
Sporophyte:
After the fertilization the archegonial cells shrivels. The wall of venter gives the 1-4 layered investment called calyptra which is of the gametophytic origin. In addition, perigynium also grows rapidly and covers the calyptra. The third covering called the involucre or perichetium is already present around the archegonia of each lobe. Thus the mature sporophyte is enveloped by three distinct protective covering; thecalyptra, the perigynium, the perichaetium. These three covering layer protect young sporogonium from desiccation. The mature sporogonium of marchantia is completely parasite on gametophyte because of the lack of chloroplast; ventral position and the covering layer avoid the light penetration. It is differentiated into foot, seta and capsule:
1. Foot: it is made up of parenchymatous cells, which are situated towards the base of archegonium .It helps in absortion of food material from the gametophyte for developing sporophyte.
2. Seta: the seta is short stalked, junction of connecting link between the foot and the capsule. It helps in the dispersal of spores.
3. Capsule: it is situated towards the neck of archegonium. It has single jacket layer of cell.
Spores and germination of spores:
When the spores fall on the suitable condition they germinated. The swell by the absorption of water. The exine ruptures and intine produce the small germ tube. The filament like structure divided and redivided to form a multicellular structure and finally gets changed into dichotomously branched thallus of marchntia.
Alternation of generation:
The life cycle of marchantia shows the distict alternation of generation. The lifecycle is completed only when the plant passes through the both the stages. The dominant phase is haploid gametophytic phase. The gametophyte reproduces sexually by male and female gametes and the result in the formation of sporophyte. The sporophyte reproduces asexually by the formation of spores. These spores give rise to the gametophyte. Themarchantia plant is a gametophyte which develops from haploid sporo. The plant body consists of dorsoventrally differentiated thallus. The antheridia produce the female gametes or egg. The antherozoids swim in the water and reach to the egg of an archegonium. Out of them only one fuses with egg together to form a diploid zygote. The diploid zygote represent of first stage of sporophyteic generation. The diploid zygote develops into complicating and elaborated structure the sporogonium or sporophyte. The sporogenous cell inside the sporophyte divided by meiosis to form a tetrad of haploid. This method of spore formation involving the meiosis is an asexual reproduction. The spores gametophytic stage. Each sporegerminates and forms a haploid gametophytic thallus of marchantia.These two generation regularly alternate to each other. This is known as alternation of generation.
Class: Musci
1. Small leafy plant, rhizoid axis leaves are present.
2. Rhizoids are only one type.
3. Presence of colmella (sterile structure).
Moss: Funaria, polytrichum
Distribution: Worldwide in distribution, cold region, moist wall, rainy season and are valvate like, dry-winter season.
Structure:
Simple leafy plant 1-more cm in the length. Green in color, root like rhizoids, unicellular, branched, and only one type and helps in fixation, absorption of water mineral, stout and cylindrical stem leaves are small, membranous green with single rib, spiral manner.
Reproduction:
Sexual reproduction:
It takes place by the formation of male and female gamete. The male and female gamete. The male and female female reproductive organ are antheridia and archegonia which lies in the association with sterile hair like St. called the paraphysis. The male and female reproductive organ are developed at the different branches of same plant,i.e . monoecious. The male branch has diversed leaves consisting group of antheridia at its apex which are usually arranged to yellow in color. The female branch has covered leaves usually produce the capsule as sporogonium.
Antheridia of the male branch are club and covered by the jacket like st. they encloses the androcytes, where the spermatozoids are formed which comes out after the brusting of antheridia. Each antherozoids are coiled and biflagellated.
Similarly archegonia of female branch are flask shape having narrow elongated neck with a row of neck canal cell and swollen venter. Inside the enter an oval ovum is formed. At the time of fertilization , the N.C.C degenerate to formed mucilaginous mass, which produce the a cane sugar that attract the antherozoid, and fuses with egg to form diploid zygote. The zygote soon develop a covering wall and called oospore. Thus the end of gametophytic and beguning of sporophytic phase . The oospore germinate to give rise to sporophyte or sporogonium. The sporogonium consist of 3 main part :
1. Foot: Itremain buried inside the archegonium nad absorb the food material for developing sporophyte.
2. Seta: it acts as stalk that helps in transportation of food as well as it helps in dehiscence of capsule.
3. Capsule:the capsule is pear shaped structure covered by the calyptra. It is the apical region consist of cap like uperculim with teeth like st. called the peristome, attach to the annukus. The peristome is hydrophobic in nature.
FEMALE CAPSULE
The main body of capsule supported by a solid base called the apophysis, consisting of conducting cells. The body of the capsule is covered by a single layer called the epidermis; they form a small gap called the stroma which helps in ex-change of gaseous. It consists of solid sterile tissue called columella, surrounded by the spore sac wall attach to the air chamber with trabaculee. Each spore sac bears a spore mother cell, which undergoes the meiosis and result in the formation of spores, these spore dispersed in dry season and when it gets a favourable condition it germinates. Each spore germinates to form the free filamentous st. called the protonema, which produce numerous bud called protonemal buds. These buds give to new gametophyte.
Alternation of generation:
In the life cycle of it is clearly seen that there are two phases. The gametophytic phase and sporophytic phase, or germination of oospore represents the sporophytic phaseswhereas gametophytic phase is the formation of gametophyte. These two phase alter to each other. That is called as alternation of generation.
Gametophytic phase is dominated over the sporophytic phase and gametophytic phase last for long period of time and is independed.
Pteridophyte:
General character:
1. They are non-floweringplant reproduce by the formation of spores.
2. They are vascular cryptogams, due to the presence of xylem an d phloem.
3. They are terrestrial in habitat some are aquatic and epiphytic.
4. They are generally herbs and few of them are shrub.
5. The plant is sporophytic which consists of roots stems and leavesand vegetative cells are diploid, they reproduce asexually by the formation of homospore and heterospore.
6. They are recognized as the oldest group of the showing the origin from the Silurian period of geological era.
7. Spore produce gametophyte, they are green, independent and are called the prothallus, prothallus produce the gametes which aredevelop in antheridium and archegonium, they may produce in same gametophyte or different gametophyte.
8. As the result of sexual reproduction produce the zygote to form the sporophyte.
9. Alternation of generation is distinct
Class: Pteropsida
Eg.Fern (Dryopteris)
Pteris
Character:
1. Perennial in habit, worldwide in distribution, present mainly in the high altitude and plains, cool, shady and moist places.
2. Structure: they are sporophytic. Root, stems and leaves are present. Stem is called the rhizome-horizontally creeping. They are perennial. Roots help in the absorption food, mineral, water.
3. Morphology: the plant body is sporophytic. This is green and can be differentiated root, stem and leaves. The stem is also known as rhizome, which is horizontally creeping. These rhizomes are covered by the small brown scales called ramenta. The roots arise from the rhizome. The leaf is petiolate and green feather like. The upper portion of petiole is called rachis, whichhas several leaflets or pinnae that bears many pinnules. The upper green part is called frond. The young leaves are coiled from the top and circinate. The phenomenon is called circinate venation.
Reproduction:
In the fern reproduction takes place by vegetative and spore formation.
Vegetative reproduction: the fern multiply by fragmentation of rhizome and development of adventitious buds.
Reproduction by spores:
1. Sporophyllus: the leaves consisting of sorii are called sporophylls.
2. Trophophylls: The leaves without sorii called trophophylls.
3. Placenta: Internally fach sorus consists of parenchymatous cushion shaped papilla called placenta.
Sexual reproduction:
The sex organs of ferns are of two types. The sperm-producing organ, the antheridium, consists of a jacket of sterile cells with sperm-producing cells inside. Antheridia may be sunken (as in the family Ophioglossaceae and Marattiaceae) or protruding. They vary in size from those with hundreds of sperm to those with only 12 or so. The egg-producing organ, the archegonium contains one gamete (sex cell), which is always located in the lower, more or less dilated portion of,the venter. The upper part of the archegonium, the neck, consists of four rows of cells containing central neck cells. The uppermost of the neck cells are the neck canal cells; the lowest cell is the ventral canal cell, which is situated just above the egg.
Fertilization:
Fertilization is attained by the ejection of sperm from antheridia. The sperm swim through free water toward simple organic acids released at the opening of the archegonium, the neck of which spreads apart at the apex, permitting the neck cells to be extruded and the sperm to swim in and penetrate the egg. The sperm are made up almost entirely of nuclear material, but their surface is provided with spiral bands of cilia—hairlike organs that effect locomotion. When the egg is fertilized, the base of the neck closes, and the embryo develops within the expanding.
PROTHALLUS ;It is a green, heart shaped, thin, flat shaped multicellular struture. It contain the deep notch at its anterior endbelow which lies the growing apex. Thus the prothallus is independent and its mode of nutrition is autotrophic. The prothallus of Dyopteris is monoecius. The sex organ and the rhizoids aresituated on the ventral surface of prothallus. The ventral side is in contact with the moist soil. The archegonia develop near the apical notch and the antheridia develop below the archegonia or near the posterior end while the unicellular brown tubular rhizoid is present. The antheridia appears earlier than the archegonia. Such condition of prothallus is called protandrouS
Alternation of generation:
Alternation of generation is distinct seen in fern; the sporophytic generation is dominant over the gametophytic generation. In ferns, the different generations exist as distinct individuals. The graceful fronds, or leaves, that we see adorn the sporophytes. If you look under the fronds of a mature plant, you’ll see structures where the spores are produced. The spores are cast from these structures onto the ground, where they develop into gametophytes. The gametophytes are tiny heart-shaped structures that are nearly invisible to the naked eye. They require a moist environment to develop and, once mature, produce sperm and egg. Like the mosses, the sperm require water to swim to the eggs, with each fertilized egg developing into the familiar, frond-bearing sporophyte.
Marchantia:
M. polymorpha
M. himalayansis these two spp. are commonly found in Nepal.
Distribution: Foot hills and the upper hills, cold countries, terai, moist, near the tap etc., appear during the rainy season, winter season.
Reproduction:
1. Vegetative reproduction:
a) By the death and decay of older part of the thallus.
b) By the production of adventitious buds
c) By the formation of Gammae.
2. Sexual reproduction:
a) Plant body is gametophytic usually reproduce sexually to produce the gametes having haploid no. chromosome.
b) Plant body is diocieous. Male thalli usually produce antheridiospore and female thalli produce the archegoniospore.
Systematic position:
Kingdom: plantae
Division:Bryophyta
Class: Hepaticopsida
Order: Marchantiales
Family: Marchantiacea
Genus: Marchantia
Morphology:
The plant body of marchantia is of gametophyte which is called a thallus. The mature thallus may attain the length of 1-10cm. it is a dark green in color and possess the prominent midrib. The midrib is marked by the shallow groove in the dorsal surface and shows the rosette type. Along the midrib, special cup like structures called gemma cups is present.
The ventral surface of the thallus bears two or more rows of violet, multicellular plate likes scales on the either side of the midrib. Scales are of two types: Ligulate and appendiculate.
The ligulate scales are small and have no appendages. Scales gives the protection to the growing point.
The ventral surface of the thallus also bears numerous rhizoids. They are pale brown, unicellular and branched. The rhizoid are of two types; smooth walled and tuberculated walled rhizoid. In the smooth walled rhizoid contain the smooth wall in the inner wall and in tuberculated rhizoids the inner wall possesses the peg like structure. They help in plant fixation and absorption of water and minerals.
In the reproductive stages thalli bears small upright, stalked structure called antheridiophores and archegoniophores. This bears male sex organ and female sex organ respectively.
Internal structure of the thallus:
A v.s. of the thallus shows the two distinct regions, the upper photosynthetic and storage region. The upper epidermis is single layered of thin walled cells. It is interrupted by several air pores. Air pores are barrel shaped consisting of 4-5 superimposed cells having both an upper and lower opening. The air pores are helps to exchange the gaseous during the respiration and photosynthesis the photosynthesis region consist of large no. of air chambers surrounded by the single celled thick 4-8 cells high septa.
The storage region consists of compactly arranged thin walled parenchymatous cells. Some cells may have single oil body or filled by the mucilage.
The lowermost layer of the storage region is lower epidermis. Rhizoids and scales are borne form certain cells of lower epidermis.
Sexual reproduction:
The sexual reproduction of the marchantia is oogamous type. Marchantia plants are dioecious , i.e. male and female sex organ develop in separate thalli. The male sex organ is the antheridia and female sex organ are called archegonia. The sex organ of marchatia is borne on special erect and stalked branches called the gametophores.
The gametophore bearing the antheridia is called antheriaophore or stalk of Male receptacle whereas the gametophore bearing archegonia is called archegoniophore or stalk of female receptacle.
Antheriodiophore:
Antheridiophore has an erect stalk which is about 2-3 cm in length. The top of antheridiophore is a flattened, slightly convex; eight lobed pelate discs each lobe of the disc has a growing point at its tip and this represent the apex of branch. On each lobe of the pellate disc, 10-12 antheridia develop in acropetl succession is the oldest being near the center and the youngest towards the tips of lobe. The ventral surface of stalk of antherodiosphore bears the scale and the rhizoids along the two grooves. The internal structure of antheridiospore is similar to that of the thallus. The antheridial chamber open outside by the pores called ostioles.
Structure of mature antheridium:
The mature antheridium is club shape structure and consists of a short multicellular and rounded or ovoid antheridium proper. The antheridium proper has a single jacket. The jacket layer encloses the single androcytes. The androcytes gets metamorphosed into motile biflagellated antherozoids or male gametes.
Dehiscence of the antheridium:
The mature antheridium dehiscence in the presence of water. When the water enter into the antheridial chamberthrough the outside, the antheridium become swell up. Some of the terminal cells the wall on coming in contact with water disintegrated. Thus the antheridium raptureand the mass of the antherozoid emerge out. The antherozoids are sets free from the mass and swim in water. Each antherozoid is long slightly coiled rod shaped st. with two flagella attach to the anterior end. The antherozoids swims in water present in the grooves of receptacles with the help of flagella.
Archegoniospore:
The archegoniospore consists of slender stalk and female receptacle. The stalks of mature archegoniosphore are comparatively longer and stouter then the antheridiospphore. The stalk is about 5-7cm in long and each surmounted by the lobe disc called the female receptacle. The disc is eight lobed with nine umbrellaslike rays dropping down.
All the archegonia are covered by the two-lipped membrane known as perichaetium or involucre. A cup shaped outgrowth that surround the archegonium called perigynium, give the protection to the archegonium.
Structure of the mature archegonium:
The mature archegonium is flask shaped structure developed on short stalk. It has swollen venter and long neck. The neck consists of the six vertical rows of jacket cells. The apical parts of neck consistof four covered cells or lid cells. A single layer of jackets surrounds the venter. The venter has one egg and one venter canal cell. The fully mature, the neck canal cell and venter canal cell disorganize and to form the mucilage mass. Which absorb the moisture and swells. The swelling exerts the pressure on lid cells so that they separate apart and the passage down to the egg is developed.
Fertilization:
It takes place in presence of water. The mucilage with the malic acids starts oozing through the mouth and that attract the antherozoids. The movement of the antherozoid in response of chemical is called chemotaxis. During the fertilization the antherozoids moving into water with female receptacle. Then a no. Of antherozoids enter the archegonium, but only one of them fuses with the egg to form the diploid zygote. The zygote developed the wall around itself and called the oospore. The fertilized egg or oospores represent the first stage of sporophytic generation.
Sporophyte:
After the fertilization the archegonial cells shrivels. The wall of venter gives the 1-4 layered investment called calyptra which is of the gametophytic origin. In addition, perigynium also grows rapidly and covers the calyptra. The third covering called the involucre or perichetium is already present around the archegonia of each lobe. Thus the mature sporophyte is enveloped by three distinct protective covering; thecalyptra, the perigynium, the perichaetium. These three covering layer protect young sporogonium from desiccation. The mature sporogonium of marchantia is completely parasite on gametophyte because of the lack of chloroplast; ventral position and the covering layer avoid the light penetration. It is differentiated into foot, seta and capsule:
1. Foot: it is made up of parenchymatous cells, which are situated towards the base of archegonium .It helps in absortion of food material from the gametophyte for developing sporophyte.
2. Seta: the seta is short stalked, junction of connecting link between the foot and the capsule. It helps in the dispersal of spores.
3. Capsule: it is situated towards the neck of archegonium. It has single jacket layer of cell.
Spores and germination of spores:
When the spores fall on the suitable condition they germinated. The swell by the absorption of water. The exine ruptures and intine produce the small germ tube. The filament like structure divided and redivided to form a multicellular structure and finally gets changed into dichotomously branched thallus of marchntia.
Alternation of generation:
The life cycle of marchantia shows the distict alternation of generation. The lifecycle is completed only when the plant passes through the both the stages. The dominant phase is haploid gametophytic phase. The gametophyte reproduces sexually by male and female gametes and the result in the formation of sporophyte. The sporophyte reproduces asexually by the formation of spores. These spores give rise to the gametophyte. Themarchantia plant is a gametophyte which develops from haploid sporo. The plant body consists of dorsoventrally differentiated thallus. The antheridia produce the female gametes or egg. The antherozoids swim in the water and reach to the egg of an archegonium. Out of them only one fuses with egg together to form a diploid zygote. The diploid zygote represent of first stage of sporophyteic generation. The diploid zygote develops into complicating and elaborated structure the sporogonium or sporophyte. The sporogenous cell inside the sporophyte divided by meiosis to form a tetrad of haploid. This method of spore formation involving the meiosis is an asexual reproduction. The spores gametophytic stage. Each sporegerminates and forms a haploid gametophytic thallus of marchantia.These two generation regularly alternate to each other. This is known as alternation of generation.
Class: Musci
1. Small leafy plant, rhizoid axis leaves are present.
2. Rhizoids are only one type.
3. Presence of colmella (sterile structure).
Moss: Funaria, polytrichum
Distribution: Worldwide in distribution, cold region, moist wall, rainy season and are valvate like, dry-winter season.
Structure:
Simple leafy plant 1-more cm in the length. Green in color, root like rhizoids, unicellular, branched, and only one type and helps in fixation, absorption of water mineral, stout and cylindrical stem leaves are small, membranous green with single rib, spiral manner.
Reproduction:
Sexual reproduction:
It takes place by the formation of male and female gamete. The male and female gamete. The male and female female reproductive organ are antheridia and archegonia which lies in the association with sterile hair like St. called the paraphysis. The male and female reproductive organ are developed at the different branches of same plant,i.e . monoecious. The male branch has diversed leaves consisting group of antheridia at its apex which are usually arranged to yellow in color. The female branch has covered leaves usually produce the capsule as sporogonium.
Antheridia of the male branch are club and covered by the jacket like st. they encloses the androcytes, where the spermatozoids are formed which comes out after the brusting of antheridia. Each antherozoids are coiled and biflagellated.
Similarly archegonia of female branch are flask shape having narrow elongated neck with a row of neck canal cell and swollen venter. Inside the enter an oval ovum is formed. At the time of fertilization , the N.C.C degenerate to formed mucilaginous mass, which produce the a cane sugar that attract the antherozoid, and fuses with egg to form diploid zygote. The zygote soon develop a covering wall and called oospore. Thus the end of gametophytic and beguning of sporophytic phase . The oospore germinate to give rise to sporophyte or sporogonium. The sporogonium consist of 3 main part :
1. Foot: Itremain buried inside the archegonium nad absorb the food material for developing sporophyte.
2. Seta: it acts as stalk that helps in transportation of food as well as it helps in dehiscence of capsule.
3. Capsule:the capsule is pear shaped structure covered by the calyptra. It is the apical region consist of cap like uperculim with teeth like st. called the peristome, attach to the annukus. The peristome is hydrophobic in nature.
FEMALE CAPSULE
The main body of capsule supported by a solid base called the apophysis, consisting of conducting cells. The body of the capsule is covered by a single layer called the epidermis; they form a small gap called the stroma which helps in ex-change of gaseous. It consists of solid sterile tissue called columella, surrounded by the spore sac wall attach to the air chamber with trabaculee. Each spore sac bears a spore mother cell, which undergoes the meiosis and result in the formation of spores, these spore dispersed in dry season and when it gets a favourable condition it germinates. Each spore germinates to form the free filamentous st. called the protonema, which produce numerous bud called protonemal buds. These buds give to new gametophyte.
Alternation of generation:
In the life cycle of it is clearly seen that there are two phases. The gametophytic phase and sporophytic phase, or germination of oospore represents the sporophytic phaseswhereas gametophytic phase is the formation of gametophyte. These two phase alter to each other. That is called as alternation of generation.
Gametophytic phase is dominated over the sporophytic phase and gametophytic phase last for long period of time and is independed.
Pteridophyte:
General character:
1. They are non-floweringplant reproduce by the formation of spores.
2. They are vascular cryptogams, due to the presence of xylem an d phloem.
3. They are terrestrial in habitat some are aquatic and epiphytic.
4. They are generally herbs and few of them are shrub.
5. The plant is sporophytic which consists of roots stems and leavesand vegetative cells are diploid, they reproduce asexually by the formation of homospore and heterospore.
7. Spore produce gametophyte, they are green, independent and are called the prothallus, prothallus produce the gametes which aredevelop in antheridium and archegonium, they may produce in same gametophyte or different gametophyte.
8. As the result of sexual reproduction produce the zygote to form the sporophyte.
9. Alternation of generation is distinct
Class: Pteropsida
Eg.Fern (Dryopteris)
Pteris
Character:
1. Perennial in habit, worldwide in distribution, present mainly in the high altitude and plains, cool, shady and moist places.
2. Structure: they are sporophytic. Root, stems and leaves are present. Stem is called the rhizome-horizontally creeping. They are perennial. Roots help in the absorption food, mineral, water.
3. Morphology: the plant body is sporophytic. This is green and can be differentiated root, stem and leaves. The stem is also known as rhizome, which is horizontally creeping. These rhizomes are covered by the small brown scales called ramenta. The roots arise from the rhizome. The leaf is petiolate and green feather like. The upper portion of petiole is called rachis, whichhas several leaflets or pinnae that bears many pinnules. The upper green part is called frond. The young leaves are coiled from the top and circinate. The phenomenon is called circinate venation.
Reproduction:
In the fern reproduction takes place by vegetative and spore formation.
Vegetative reproduction: the fern multiply by fragmentation of rhizome and development of adventitious buds.
Reproduction by spores:
1. Sporophyllus: the leaves consisting of sorii are called sporophylls.
2. Trophophylls: The leaves without sorii called trophophylls.
3. Placenta: Internally fach sorus consists of parenchymatous cushion shaped papilla called placenta.
Sexual reproduction:
The sex organs of ferns are of two types. The sperm-producing organ, the antheridium, consists of a jacket of sterile cells with sperm-producing cells inside. Antheridia may be sunken (as in the family Ophioglossaceae and Marattiaceae) or protruding. They vary in size from those with hundreds of sperm to those with only 12 or so. The egg-producing organ, the archegonium contains one gamete (sex cell), which is always located in the lower, more or less dilated portion of,the venter. The upper part of the archegonium, the neck, consists of four rows of cells containing central neck cells. The uppermost of the neck cells are the neck canal cells; the lowest cell is the ventral canal cell, which is situated just above the egg.
Fertilization:
Fertilization is attained by the ejection of sperm from antheridia. The sperm swim through free water toward simple organic acids released at the opening of the archegonium, the neck of which spreads apart at the apex, permitting the neck cells to be extruded and the sperm to swim in and penetrate the egg. The sperm are made up almost entirely of nuclear material, but their surface is provided with spiral bands of cilia—hairlike organs that effect locomotion. When the egg is fertilized, the base of the neck closes, and the embryo develops within the expanding.
PROTHALLUS ;It is a green, heart shaped, thin, flat shaped multicellular struture. It contain the deep notch at its anterior endbelow which lies the growing apex. Thus the prothallus is independent and its mode of nutrition is autotrophic. The prothallus of Dyopteris is monoecius. The sex organ and the rhizoids aresituated on the ventral surface of prothallus. The ventral side is in contact with the moist soil. The archegonia develop near the apical notch and the antheridia develop below the archegonia or near the posterior end while the unicellular brown tubular rhizoid is present. The antheridia appears earlier than the archegonia. Such condition of prothallus is called protandrouS
Alternation of generation:
Alternation of generation is distinct seen in fern; the sporophytic generation is dominant over the gametophytic generation. In ferns, the different generations exist as distinct individuals. The graceful fronds, or leaves, that we see adorn the sporophytes. If you look under the fronds of a mature plant, you’ll see structures where the spores are produced. The spores are cast from these structures onto the ground, where they develop into gametophytes. The gametophytes are tiny heart-shaped structures that are nearly invisible to the naked eye. They require a moist environment to develop and, once mature, produce sperm and egg. Like the mosses, the sperm require water to swim to the eggs, with each fertilized egg developing into the familiar, frond-bearing sporophyte.