Notes on Marsilea: Systematic Position, Morphology, Gametophyte and Life Cycle

Marsilea
Systematic Position:
Division: Filicocophyta
Class: Leptosporangiopsida
Family: Marsiliaceae
Genus: Marsilea
  • Species:M. hirsuta, M.rajastthanensis , M.vestita (Amphibious), M.quadrifolia
  • Habitat: Aquatic or semi aquatic habitats
Plant Body: 
  • The plant body is the sporophyte  differentiated into Creeping rhizome, root and leaves.
  • Creeping rhizome: Grows beneath the soil, highly branched with nodes and internodes. Roots and leaves arise from the nodes
  • Leaves: rhizome forms single leaf from a node. Leaf consisits of long petiole with pinnae at the tip
  • Function: photosynthesis
  • Roots arising from node
Other features: 
  • Heterosporous nature.
  • Leptosporangiate
Life cycle: Heteromorphic alternation of generation.
Gametophyte or Prothallus:
•Microspore produces male gametophyte & megaspore produces female gametophyte.
•Microspore are globular with cellulosic exine and intine
•Male gametophyte develops within the microspore wall and produces many spirally coiled multi-flagellated antherozoids which swims towards megaspore
•Megaspores are large in size with exine and intine
•Megaspores germinates within megasporangium forming female gemetophyte bearing archegonia and a basal enlarged prothallial cell.
•Water is essential for fertilization
•The young sporophyte remains attached to the megaspore for some time later falls to the ground and form roots and become independent
Vegetative Reproduction: Tubers which can withstand unfavorable condition
Image credits
Marsilea
Systematic Position:
Division: Filicocophyta
Class: Leptosporangiopsida
Family: Marsiliaceae
Genus: Marsilea
  • Species:M. hirsuta, M.rajastthanensis , M.vestita (Amphibious), M.quadrifolia
  • Habitat: Aquatic or semi aquatic habitats
Plant Body: 
  • The plant body is the sporophyte  differentiated into Creeping rhizome, root and leaves.
  • Creeping rhizome: Grows beneath the soil, highly branched with nodes and internodes. Roots and leaves arise from the nodes
  • Leaves: rhizome forms single leaf from a node. Leaf consisits of long petiole with pinnae at the tip
  • Function: photosynthesis
  • Roots arising from node
Other features: 
  • Heterosporous nature.
  • Leptosporangiate
Life cycle: Heteromorphic alternation of generation.
Gametophyte or Prothallus:
•Microspore produces male gametophyte & megaspore produces female gametophyte.
•Microspore are globular with cellulosic exine and intine
•Male gametophyte develops within the microspore wall and produces many spirally coiled multi-flagellated antherozoids which swims towards megaspore
•Megaspores are large in size with exine and intine
•Megaspores germinates within megasporangium forming female gemetophyte bearing archegonia and a basal enlarged prothallial cell.
•Water is essential for fertilization
•The young sporophyte remains attached to the megaspore for some time later falls to the ground and form roots and become independent
Vegetative Reproduction: Tubers which can withstand unfavorable condition
Image credits
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Notes on Sporocarp of Marsilea -Morphology and Anatomy

Sporocarp of Marsilea :
Sporocarp of Marsilea
•Marselia is heterosporous and Leptosporangiate: It bears two kinds of spores; microspores and megaspores produced inside microspoarngium and megasporangium
Sporangia are formed inside specialized structures called sporocarps
•Sporocarps are formed from the petiole of the leaf
When young it is green and soft with hairs. On maturity becomes hard and turns brown
Each sporocarp is attached to the petiole by means of stalk called pedicel.
Origin of Sporocarp of Marsilea: Two views

•       1. Laminar concept by Bower: Sporocarp is formed by the fusion of one or more leaflets or pinnae
2. ‘Whole leaf concept’ by Johnson: Sporocarp is formed by the whole leaf
Morphology of Sporocarp: 
  • Each sporocarp is oval or oblong body or bean seed shaped
  • The portion where the sporocarp attaches with the pedicel is called the raphe
  • Above Raphe the sporocarp has two horn shaped parts called tubercles.
Anatomy Sporocarp:
Anatomy Sporocarp of Marsilea
Image credits
Bean shaped structure with bilateral symmetry
•Thick wall consists of three layers. Single layered epidermis wit h stomata
Hypodermis consist of outer layer of thick walled cells and inner layer of thin walled cells and contain chloroplast.
•Below hypodermis is a gelatinous ring of parenchymatous cells more prominent at the dorsal side.
The central cavity contains 2 rows of elongated sori one in each half. The no. of sori may vary from 2-20
•Each sorus arise from the placentum
Each sorus is surrounded  by its own indusium. It contains a megasporangium at the tip and 2 microsporangia one on either side of the placentum
Each sporangium has a separate vascular connection
Sporocarp of Marsilea :
Sporocarp of Marsilea
•Marselia is heterosporous and Leptosporangiate: It bears two kinds of spores; microspores and megaspores produced inside microspoarngium and megasporangium
Sporangia are formed inside specialized structures called sporocarps
•Sporocarps are formed from the petiole of the leaf
When young it is green and soft with hairs. On maturity becomes hard and turns brown
Each sporocarp is attached to the petiole by means of stalk called pedicel.
Origin of Sporocarp of Marsilea: Two views

•       1. Laminar concept by Bower: Sporocarp is formed by the fusion of one or more leaflets or pinnae
2. ‘Whole leaf concept’ by Johnson: Sporocarp is formed by the whole leaf
Morphology of Sporocarp: 
  • Each sporocarp is oval or oblong body or bean seed shaped
  • The portion where the sporocarp attaches with the pedicel is called the raphe
  • Above Raphe the sporocarp has two horn shaped parts called tubercles.
Anatomy Sporocarp:
Anatomy Sporocarp of Marsilea
Image credits
Bean shaped structure with bilateral symmetry
•Thick wall consists of three layers. Single layered epidermis wit h stomata
Hypodermis consist of outer layer of thick walled cells and inner layer of thin walled cells and contain chloroplast.
•Below hypodermis is a gelatinous ring of parenchymatous cells more prominent at the dorsal side.
The central cavity contains 2 rows of elongated sori one in each half. The no. of sori may vary from 2-20
•Each sorus arise from the placentum
Each sorus is surrounded  by its own indusium. It contains a megasporangium at the tip and 2 microsporangia one on either side of the placentum
Each sporangium has a separate vascular connection
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Function of Colchicine in Cell division

Colchicine is an alkaloid widely used in plant breeding for doubling the chromosome number. Colchicine is extracted from the corms of autumn crocus (Colchicine autumnale). The alkaloid does not allow the formation of spindle because it prevents assembly of microtubules. It is, therefore, called ‘mitotic poison’. Thus mitotic poisons are substances that affect the cells in mitosis or prevent them from entering it.
autumn crocus : Colchicine autumnale

Colchicine 










Colchicine holds the cells in metaphase. The enzyme ribonuclease is prophase poison. Colchicine does not inhibit chromosome replication. As a result the Colchicine treated to  meristematic cells show doubling of chromosomes. This property of colchicine is being used to have polyploidy.
Colchicine is an alkaloid widely used in plant breeding for doubling the chromosome number. Colchicine is extracted from the corms of autumn crocus (Colchicine autumnale). The alkaloid does not allow the formation of spindle because it prevents assembly of microtubules. It is, therefore, called ‘mitotic poison’. Thus mitotic poisons are substances that affect the cells in mitosis or prevent them from entering it.
autumn crocus : Colchicine autumnale

Colchicine 










Colchicine holds the cells in metaphase. The enzyme ribonuclease is prophase poison. Colchicine does not inhibit chromosome replication. As a result the Colchicine treated to  meristematic cells show doubling of chromosomes. This property of colchicine is being used to have polyploidy.
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Functions of Inorganic Elements in Plants

The plant require inorganic elements in large amounts or in traces for several functions of the plant body.
The important functions are
  • They serve as constitute of protoplast and cell wall.
  • Minerals ions of the vacuole sap influence the OP of cell.
  • Some mineral elements serve as activators or co factors of enzymes.minerals
  • Inorganic elements enter into the synthesis of several biologically important molecules.
  • Nitrogen is an important constituent of proteins, amino acids, RNA, DNA, vitamins, hormones, cytochromes, chlorophylls, co enzymes etc.
  • Phosphorus is the structural constituent of nucleic acids, nucleotides.
  • Magnesium is the metallic part of chlorophyll.
  • Calcium is a major components of calcium pectate of the middle lamella.
  • Sulphur is an important constituent of certain essential amino acids such as cysteine, cystine and methionine.
  • Potassium ions play an active role in the opening and closing of stomata.
  • Magnesium is an integral part of chloroplast and maintains ribosome structure.
  • Boron is required in pollen germination
  • Molybdenum helps in ion absorption and translocation.

The plant require inorganic elements in large amounts or in traces for several functions of the plant body.
The important functions are
  • They serve as constitute of protoplast and cell wall.
  • Minerals ions of the vacuole sap influence the OP of cell.
  • Some mineral elements serve as activators or co factors of enzymes.minerals
  • Inorganic elements enter into the synthesis of several biologically important molecules.
  • Nitrogen is an important constituent of proteins, amino acids, RNA, DNA, vitamins, hormones, cytochromes, chlorophylls, co enzymes etc.
  • Phosphorus is the structural constituent of nucleic acids, nucleotides.
  • Magnesium is the metallic part of chlorophyll.
  • Calcium is a major components of calcium pectate of the middle lamella.
  • Sulphur is an important constituent of certain essential amino acids such as cysteine, cystine and methionine.
  • Potassium ions play an active role in the opening and closing of stomata.
  • Magnesium is an integral part of chloroplast and maintains ribosome structure.
  • Boron is required in pollen germination
  • Molybdenum helps in ion absorption and translocation.

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7 Important Characters of Malvaceae (Mallow Family) plants

Hibiscus rosa-sinensis (Malvaceae )
Systematic position:
Polypetalae, Thalamiflorae, Malvales
Following are the Important characters of Malvaceae:

1. Hairs on the body and mucilage in the tissues.

2. Alternate phyllotaxy and stipute leaves.

3.  Multicosatte reticulte venation of the leaves.

4. Presence of epicalyx.

5. Monodelphous stamens with monothecous, reniform extrose anthers.

6. Spinous pollen


7. Axile placentation.
Example of Malvaceae plants:
Abutilon, Althaea,  Gossypium , Hibiscus, Malvastrum, Malva, Sida,
Hibiscus rosa-sinensis (Malvaceae )
Systematic position:
Polypetalae, Thalamiflorae, Malvales
Following are the Important characters of Malvaceae:

1. Hairs on the body and mucilage in the tissues.

2. Alternate phyllotaxy and stipute leaves.

3.  Multicosatte reticulte venation of the leaves.

4. Presence of epicalyx.

5. Monodelphous stamens with monothecous, reniform extrose anthers.

6. Spinous pollen


7. Axile placentation.
Example of Malvaceae plants:
Abutilon, Althaea,  Gossypium , Hibiscus, Malvastrum, Malva, Sida,
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7 Important Characters of Euphorbiaceae (Spurge Family)


Euphorbia hirta (Euphorbiaceae)

Systematic Position: 
Monochlamydeae (Apetalae), Unisexuales

Following are the most important characters of Euphorbiace:
1. Xerophytic nature

2. Presence of Latex

3. Dwarf  Branches

4. Reduced, unisexual flowers

5. Tricarpellary trilocular superior ovary with Pendulous ovule on axile placenta.


6. Schizocarpic fruit.

7. Carunculate seeds
Example of  Euhorbiaceae plants: 
Croton, Euphorbia, Hevea, Jatropha, Manihot, Phyllanthus and Ricinus.

Euphorbia hirta (Euphorbiaceae)

Systematic Position: 
Monochlamydeae (Apetalae), Unisexuales

Following are the most important characters of Euphorbiace:
1. Xerophytic nature

2. Presence of Latex

3. Dwarf  Branches

4. Reduced, unisexual flowers

5. Tricarpellary trilocular superior ovary with Pendulous ovule on axile placenta.


6. Schizocarpic fruit.

7. Carunculate seeds
Example of  Euhorbiaceae plants: 
Croton, Euphorbia, Hevea, Jatropha, Manihot, Phyllanthus and Ricinus.
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Quiz on Bryophytes

1. Bryophytes include
liverworts and ferns
foerns and mosses
mosses and liverworts
none of these
2. The simplest known sporophyte among Bryophyta is seen in
Riccia
Funaria
Marchantia
Anthoceros
3. Spore mother cell in Bryophytes is
haploid in nature
diploid
triploid
tetraploid
4. The peat moss belongs to the order
Sphagnales
Bryales
Andreaeales
Anthocerotales
5. Elaters are seen in
antheridium
archegonium
sporogonium
none of these
6. In Funaria capsule, the peristome consist of
16 teeth
32 teeth
64 teeth
128 teeth
7. Leptoids are present in
Marchantia
Anthoceros
Sphagnum
Polytrichum
8. Protonema is found in
Anthoceros
Marchantia
Funaria
Riccia
9. In Sphagnum the spore sac is
spindle shaped
arc shaped
disc shaped
dome shaped
10. The advanced sporophyte is seen in
Marchantia
Porella
Anthoceros
Sphagnum
Score =
Correct answers:
Image Credit: Heino Lepp
1. Bryophytes include
liverworts and ferns
foerns and mosses
mosses and liverworts
none of these
2. The simplest known sporophyte among Bryophyta is seen in
Riccia
Funaria
Marchantia
Anthoceros
3. Spore mother cell in Bryophytes is
haploid in nature
diploid
triploid
tetraploid
4. The peat moss belongs to the order
Sphagnales
Bryales
Andreaeales
Anthocerotales
5. Elaters are seen in
antheridium
archegonium
sporogonium
none of these
6. In Funaria capsule, the peristome consist of
16 teeth
32 teeth
64 teeth
128 teeth
7. Leptoids are present in
Marchantia
Anthoceros
Sphagnum
Polytrichum
8. Protonema is found in
Anthoceros
Marchantia
Funaria
Riccia
9. In Sphagnum the spore sac is
spindle shaped
arc shaped
disc shaped
dome shaped
10. The advanced sporophyte is seen in
Marchantia
Porella
Anthoceros
Sphagnum
Score =
Correct answers:
Image Credit: Heino Lepp
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5 Stages in Life cycle of Puccinia

Kingdom:  Fungi
Phylum:  Basidiomycota
Class:  Pucciniomycetes
Order:  Pucciniales
Family:  Pucciniaceae
Genus:  Puccinia
(according to the latest classification system)
P. graminis is an obligate parasite, and heteroecious rust.
P. graminis causes black rust of wheat
Heteroecious fungus: 
Life cycle is completed on two different hosts. The wheat plant is called the primary host where dikaryophase is completed and the barberry plant is secondary or alternate host where haplophase is completed. Both hosts are required to complete the life cycle.
Puccinia life cycle summarized in five stages
Summary of life cycle of Puccinia
Life cycle in Wheat
• Wheat is the primary host upon which dikaryophase of the pathogen is completed
• This phase consists of well developed branched, septate, dikaryotic vegetative mycelium and two spore stages namely, uridenial stage and telial stage.

Stage I in Wheat:  Aecidiospores germinates on wheat; later dikaryotic hyphae               form Uredia bearing uredospores. 
•     In wheat, primary infection starts with the germination of aecidiospore formed on the aecidial cups on the lower surface of infected barberry leaves.
        Aecidiospores are binucleate and on germination form primary hypha which enters the host through stomata. It forms haustoria for absorbing nutrients. This binucleate hypha or dikaryotic hyphae produces two kinds of spores uredopores and teleutospores
Uredenial Stage
       A few days after infection, dikaryotic mycelium form a specialized pustules or sori on the surface of the host tissue called uredosorus. Uredospores are formed on uredosorus.
       Uredospores are produced on long stalks and each spore is bi-nucleate, red or orange coloured and oval to round in outline.
       Large number of uredospores are formed in uredosorous and the pressure exerted by the developing uredospores breaks host epidermis to expose the uredospores.
       A uredospore can infect only a wheat plant. After falling on a suitable host under favorable condition it germinates by forming germ tube. Later it forms an elongated vesicle called appresorium on reaching stoma. Appresorium give rise to infection hyphae producing uredosorus and uredospores again within 10-12 days after germination. Thus, these spores cause several successive secondary infections during the season, and spread the fungus and the disease from field to field.
       The uredospore infections are seen as reddish brown pustules on leaves and stem of wheat plant. Therefore, uredineal stage also called as “red stage” or “summer stage”
Stage 2 in Wheat: Seasonal change triggers the formation of Telia or teleutosorus bearing teleutospores in the place of uredosorus.
Telial stage
       Towards the end of the growing season of wheat crop, when the conditions are unfavorable for uredospores, uredosori produce another kind of spores called teleutospores. Now the red stage is gradually replaced by “black stage” or causes black rust of wheat
       At first, teleutospores are formed on uredosorus, later teleutospores are formed in specialized pustules called teleutosori and the stage is called telial stage.
       Teleutospores are produced on long stalks and each spore is two celled, binucleated cells, spindle shaped and dark brown or black in colours with thick, smooth wall.
       Large number of teleutospores is formed in teleutosorous and the pressure of growing breaks host epidermis to expose the teleutospores.
       The two nuclei in each cell of teleutospores fuse to form a diploid nucleus at maturity (karyotype). This diploid spores undergoes a resting period to tide over winter.
Stage 3 in Wheat:  Teleutospores produce promycelia bearing basidiospores on basidium.
Basidial stage on Wheat
       In the following spring, teleutospores germinate by forming promycelium. Promycelium comes out of the germ pore of each cell. The diploid nucleus enters promycelium and undergoes meiosis forming four haploid nuclei.
       These nucleus are separated by the formation of a cross wall. This four celled structure is called basidium.
       Each haploid cell of the basidium produces a slender, short, lateral, tube-like structure known as sterigma. Later, basidiospores is produced at the end of each sterigma. Basidiospore represent the beginning of haploid phase.
       Thus, from a single cell of teleutospore four haploid, unicellular, uninucleate basidiospores are formed. Two of the basidiospore produced belong to the ‘+’ strain and the other two ‘–’ strain.
       Basidiospores are released by an explosive mechanism and carried away by wind.
       The haplophase consists of a haploid vegetative mycelium and a spore stages, the pycnidial stage. Dikaryophase starts with aecidiospore.
       Each haploid cell of the basidium produces a slender, short, lateral, tube-like structure known as sterigma. Later, basidiospores is produced at the end of each sterigma. Basidiospore represent the beginning of haploid phase.
       Thus, from a single cell of teleutospores, four haploid, unicellular, uninucleate basidiospores are formed. Two of the basidiospore produced belong to the ‘+’ strain and the other two ‘–’ strain.
       Basidiospores are releases by an explosive mechanism and carried away by wind.
Stage 4 in BarberryBasidiospores germinate forming extensive hyphae with Spermogonia or Pycnia bearing spermatia and receptive hyphae (pycnidial stage).
Basidial stage on Barberry
       Basidiospores cannot germinate on wheat. It germinates only upon falling on the alternate host, the barberry.
       On the leaf of Barberry plant, basidiospores germinates forming germ tube and grows extensively forming haploid, septate, uninucleate mycelium.
       Mycelia of both strains co exist in the same leaf. They produce pycnidial stage on the upper surface and aecidial stage on the lower surface.
Pycnidial stage or Spermagonial stage
       The haplomycelium forms dense mats of hyphae on upper epidermis which later organize to form pycnidium of both strains.
       Spermagonium or pycnidium is a small flask shaped structure that opens to the outside by a small pore called ostiole. The ostiole is guarded at the edge by the long, delicate, sterile hyphae known as periphysis.
       There are two kinds of hyphae in a pycnidium. Long delicate receptive hyphae that extends beyond the ostiole and slender, short, vertical, uninucleate hyphae which arise form the base of the spermagonium  called spermatial hyphae. It bears spermatia or pycniopores at the tip.
       The spermatia are unicellular, small, oval thin walled cells. A pycnidium gives rise to only + or ‘–‘ spermatium
       The transfer of spermatium of one strain to the pycnidium containing receptive hyphae of opposite strain is affected by insects.
       The spermatia of one strain when comes in contact with the tip of the receptive hyphae of opposite strain lead to the dissolution of intervening wall at the point of contact resulting in the formation of a dikaryon (two nuclei in common protoplasm without fusion). This pair of nuclei of opposite strains is called a dikaryon and this process is called dikaryotization. 
graphical representation of Puccinia
Stage 5 in BarberryAecidia bearing aecidiospores produced in Barberry which infects wheat again.
Aecidial stage on Barberry
       From this dikaryotic cell, dikaryotic mycelium is formed which later organize to form the aecidia in the mesophyll of barberry leaf.
       Aecidia are cup shaped structures on which aecidiospores are produced. A mature aecidiospores are unicellular, thick walled, bi-nucleate and orange yellow coloured with many germ pores.
       The aeciospores are disseminated by wind. They are incapable of germination in barberry plant. It germinates when falling on wheat plant, the primary host. Thus the life cycle is completed.
Kingdom:  Fungi
Phylum:  Basidiomycota
Class:  Pucciniomycetes
Order:  Pucciniales
Family:  Pucciniaceae
Genus:  Puccinia
(according to the latest classification system)
P. graminis is an obligate parasite, and heteroecious rust.
P. graminis causes black rust of wheat
Heteroecious fungus: 
Life cycle is completed on two different hosts. The wheat plant is called the primary host where dikaryophase is completed and the barberry plant is secondary or alternate host where haplophase is completed. Both hosts are required to complete the life cycle.
Puccinia life cycle summarized in five stages
Summary of life cycle of Puccinia
Life cycle in Wheat
• Wheat is the primary host upon which dikaryophase of the pathogen is completed
• This phase consists of well developed branched, septate, dikaryotic vegetative mycelium and two spore stages namely, uridenial stage and telial stage.

Stage I in Wheat:  Aecidiospores germinates on wheat; later dikaryotic hyphae               form Uredia bearing uredospores. 
•     In wheat, primary infection starts with the germination of aecidiospore formed on the aecidial cups on the lower surface of infected barberry leaves.
        Aecidiospores are binucleate and on germination form primary hypha which enters the host through stomata. It forms haustoria for absorbing nutrients. This binucleate hypha or dikaryotic hyphae produces two kinds of spores uredopores and teleutospores
Uredenial Stage
       A few days after infection, dikaryotic mycelium form a specialized pustules or sori on the surface of the host tissue called uredosorus. Uredospores are formed on uredosorus.
       Uredospores are produced on long stalks and each spore is bi-nucleate, red or orange coloured and oval to round in outline.
       Large number of uredospores are formed in uredosorous and the pressure exerted by the developing uredospores breaks host epidermis to expose the uredospores.
       A uredospore can infect only a wheat plant. After falling on a suitable host under favorable condition it germinates by forming germ tube. Later it forms an elongated vesicle called appresorium on reaching stoma. Appresorium give rise to infection hyphae producing uredosorus and uredospores again within 10-12 days after germination. Thus, these spores cause several successive secondary infections during the season, and spread the fungus and the disease from field to field.
       The uredospore infections are seen as reddish brown pustules on leaves and stem of wheat plant. Therefore, uredineal stage also called as “red stage” or “summer stage”
Stage 2 in Wheat: Seasonal change triggers the formation of Telia or teleutosorus bearing teleutospores in the place of uredosorus.
Telial stage
       Towards the end of the growing season of wheat crop, when the conditions are unfavorable for uredospores, uredosori produce another kind of spores called teleutospores. Now the red stage is gradually replaced by “black stage” or causes black rust of wheat
       At first, teleutospores are formed on uredosorus, later teleutospores are formed in specialized pustules called teleutosori and the stage is called telial stage.
       Teleutospores are produced on long stalks and each spore is two celled, binucleated cells, spindle shaped and dark brown or black in colours with thick, smooth wall.
       Large number of teleutospores is formed in teleutosorous and the pressure of growing breaks host epidermis to expose the teleutospores.
       The two nuclei in each cell of teleutospores fuse to form a diploid nucleus at maturity (karyotype). This diploid spores undergoes a resting period to tide over winter.
Stage 3 in Wheat:  Teleutospores produce promycelia bearing basidiospores on basidium.
Basidial stage on Wheat
       In the following spring, teleutospores germinate by forming promycelium. Promycelium comes out of the germ pore of each cell. The diploid nucleus enters promycelium and undergoes meiosis forming four haploid nuclei.
       These nucleus are separated by the formation of a cross wall. This four celled structure is called basidium.
       Each haploid cell of the basidium produces a slender, short, lateral, tube-like structure known as sterigma. Later, basidiospores is produced at the end of each sterigma. Basidiospore represent the beginning of haploid phase.
       Thus, from a single cell of teleutospore four haploid, unicellular, uninucleate basidiospores are formed. Two of the basidiospore produced belong to the ‘+’ strain and the other two ‘–’ strain.
       Basidiospores are released by an explosive mechanism and carried away by wind.
       The haplophase consists of a haploid vegetative mycelium and a spore stages, the pycnidial stage. Dikaryophase starts with aecidiospore.
       Each haploid cell of the basidium produces a slender, short, lateral, tube-like structure known as sterigma. Later, basidiospores is produced at the end of each sterigma. Basidiospore represent the beginning of haploid phase.
       Thus, from a single cell of teleutospores, four haploid, unicellular, uninucleate basidiospores are formed. Two of the basidiospore produced belong to the ‘+’ strain and the other two ‘–’ strain.
       Basidiospores are releases by an explosive mechanism and carried away by wind.
Stage 4 in BarberryBasidiospores germinate forming extensive hyphae with Spermogonia or Pycnia bearing spermatia and receptive hyphae (pycnidial stage).
Basidial stage on Barberry
       Basidiospores cannot germinate on wheat. It germinates only upon falling on the alternate host, the barberry.
       On the leaf of Barberry plant, basidiospores germinates forming germ tube and grows extensively forming haploid, septate, uninucleate mycelium.
       Mycelia of both strains co exist in the same leaf. They produce pycnidial stage on the upper surface and aecidial stage on the lower surface.
Pycnidial stage or Spermagonial stage
       The haplomycelium forms dense mats of hyphae on upper epidermis which later organize to form pycnidium of both strains.
       Spermagonium or pycnidium is a small flask shaped structure that opens to the outside by a small pore called ostiole. The ostiole is guarded at the edge by the long, delicate, sterile hyphae known as periphysis.
       There are two kinds of hyphae in a pycnidium. Long delicate receptive hyphae that extends beyond the ostiole and slender, short, vertical, uninucleate hyphae which arise form the base of the spermagonium  called spermatial hyphae. It bears spermatia or pycniopores at the tip.
       The spermatia are unicellular, small, oval thin walled cells. A pycnidium gives rise to only + or ‘–‘ spermatium
       The transfer of spermatium of one strain to the pycnidium containing receptive hyphae of opposite strain is affected by insects.
       The spermatia of one strain when comes in contact with the tip of the receptive hyphae of opposite strain lead to the dissolution of intervening wall at the point of contact resulting in the formation of a dikaryon (two nuclei in common protoplasm without fusion). This pair of nuclei of opposite strains is called a dikaryon and this process is called dikaryotization. 
graphical representation of Puccinia
Stage 5 in BarberryAecidia bearing aecidiospores produced in Barberry which infects wheat again.
Aecidial stage on Barberry
       From this dikaryotic cell, dikaryotic mycelium is formed which later organize to form the aecidia in the mesophyll of barberry leaf.
       Aecidia are cup shaped structures on which aecidiospores are produced. A mature aecidiospores are unicellular, thick walled, bi-nucleate and orange yellow coloured with many germ pores.
       The aeciospores are disseminated by wind. They are incapable of germination in barberry plant. It germinates when falling on wheat plant, the primary host. Thus the life cycle is completed.
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Ecosystem-Definition, Different types and Examples


  • The term ecosystem was coined by A.G. Tansley (1935)
  • It is a “Life supporting system”
  • Eco=region of space where organisms live
  • System =formed by interacting organism

Pond ecosystem

Definition: Ecosystem refers to the interactions of organisms with one another and with their environment in which they occur.
It is a “Life supporting system"
Ecosystem may be of two types: Natural and Artificial (Manmade)
Examples of ecosystem


The above figure gives you a summary of different types of ecosystems and examples of each type.
Each ecosystem may be considered as two layers, six structural components and six processes.
i)  Layers: Autotrophic layer and heterotrophic layer
Autotrophic layer or green belt within which the buildup of complex substances predominates using solar energy.
Heterotrophic layer or brown layer within which further manipulation and decomposition of the complex substances predominates.

ii)Structural components:
  • Inorganic substances: it involved n material cycles.
  • organic compounds that link biotic and Abiotic sectors.
  • Climatic regime :example rain fall, temperature
  • Producers mainly green plants that manufacture food from sunlight (light energy)
  • Consumers animals that consume other organisms and particulate organic matter-primary and secondary consumers.
  • Decomposers chiefly microbes that breakdown  complex compounds with release of products that are recycled by plants
iii)  Processes:
  • Energy flow
  • Food chains
  • Water and mineral nutrient cycles
  • Development and evolution (Succession)
  • Control (Cybernetics)

  • The term ecosystem was coined by A.G. Tansley (1935)
  • It is a “Life supporting system”
  • Eco=region of space where organisms live
  • System =formed by interacting organism

Pond ecosystem

Definition: Ecosystem refers to the interactions of organisms with one another and with their environment in which they occur.
It is a “Life supporting system"
Ecosystem may be of two types: Natural and Artificial (Manmade)
Examples of ecosystem


The above figure gives you a summary of different types of ecosystems and examples of each type.
Each ecosystem may be considered as two layers, six structural components and six processes.
i)  Layers: Autotrophic layer and heterotrophic layer
Autotrophic layer or green belt within which the buildup of complex substances predominates using solar energy.
Heterotrophic layer or brown layer within which further manipulation and decomposition of the complex substances predominates.

ii)Structural components:
  • Inorganic substances: it involved n material cycles.
  • organic compounds that link biotic and Abiotic sectors.
  • Climatic regime :example rain fall, temperature
  • Producers mainly green plants that manufacture food from sunlight (light energy)
  • Consumers animals that consume other organisms and particulate organic matter-primary and secondary consumers.
  • Decomposers chiefly microbes that breakdown  complex compounds with release of products that are recycled by plants
iii)  Processes:
  • Energy flow
  • Food chains
  • Water and mineral nutrient cycles
  • Development and evolution (Succession)
  • Control (Cybernetics)
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Notes on Equisetum Systematic Position, Morphology, Gametophyte and Life Cycle


Systematic Position
Division: Sphenophyta
Class: Calamopsida
Family: Equisitaceae
Genus: Equisetum (Horse tails, Scouring rushes) Only living member


Species: Common species include E. arvense (road side), E. debile (river side)Habitat: grows in swampy soil along river side or sandy road sides
Habit: Bushy, perennial herbs
Equisetum: Plant body
Equisetum Plant body

  •     Sporophytic plant body
  •       Differentiated into root, stem and leaves
  •      Creeping or erect plant body
  •      Stem: consist of underground rhizome and upright green aerial branches.
  •       Jointed stem with nodes and internodes, internodes with longitudinal ridges and furrows and hollow interior
  •      Silica deposits in stem make it rough (Scouring rushes)
  •        Leaves: nodes with small, sessile microphyllous scale leaves in whorls
  •        Function: photosynthesis
  •      Fertile branches bear strobili after some vegetative growth
  •        Roots: Adventitious roots arise from the nodes of rhizome
  •      Other features: Homosporous nature, Eusporangiate
Equisetum Stem Anatomy T.S
     Vegetative Reproduction:  Fragmentation of rhizome, Tubers formed on rhizome
Strobilus or structure of cone
STROBILUS OF EQUISETUM

  •  Equisetum is homosporous and Eusporangiate
  •   Strobili are borne terminally and singly on aerial fertile branches.
  • Strobilus consists of a central axis on which stalked sporangiophores with sporangium are arranged in whorls
     Sporangiophore
·         Umbrella shaped structure with a slender stalk and a hexagonal peltate disc
·         The underside of peltate disc bears variable number of sac like sporangia
·         The number of sporangia in each sporangiophore may vary from 5-10
·         Sporangium consists of a 2 cell thick wall, with large number of homosporous spores.  Dehiscence along longitudinal slit. Spores are dispersed by  wind with the help of elaters
Spores and Elators
          Spores are Green, large, uninucleate, spherical, chloroplast containing structures with exine, intine and outermost epispore
          Elaters are spirally coiled , spoon shaped hygroscopic structures formed from epispore of haploid spore
          Each spore has 4 spirally arranged hygroscopic elaters
          Function: helps in dehiscence of sporangium and spore dispersal
Gametophyte or prothallus of Equisetum
Gametophyte or prothallus of Equisetum

  •     Spores falling on suitable substratum germinate to form green prothallus with rhizoids for fixation.
  •      Prothallus consists of a basal disc and number of green vertical lobes.
  •       Monoecious or bisexual: both antheridia and archegonia are present.
  •      Antheridia may occur on vertical lobes or basal disc embedded.
  •       Antheridium produces 256-512multiflagellate, spirally coiled spermatozoids.
  •      Archegonia flask shaped structures at the base of vertical lobes.
  •       Fusion forms embryo which give rise to new plant.
     Life cycle: Homomorphic alternation of generation
Life cycle of Equisetum

Systematic Position
Division: Sphenophyta
Class: Calamopsida
Family: Equisitaceae
Genus: Equisetum (Horse tails, Scouring rushes) Only living member


Species: Common species include E. arvense (road side), E. debile (river side)Habitat: grows in swampy soil along river side or sandy road sides
Habit: Bushy, perennial herbs
Equisetum: Plant body
Equisetum Plant body

  •     Sporophytic plant body
  •       Differentiated into root, stem and leaves
  •      Creeping or erect plant body
  •      Stem: consist of underground rhizome and upright green aerial branches.
  •       Jointed stem with nodes and internodes, internodes with longitudinal ridges and furrows and hollow interior
  •      Silica deposits in stem make it rough (Scouring rushes)
  •        Leaves: nodes with small, sessile microphyllous scale leaves in whorls
  •        Function: photosynthesis
  •      Fertile branches bear strobili after some vegetative growth
  •        Roots: Adventitious roots arise from the nodes of rhizome
  •      Other features: Homosporous nature, Eusporangiate
Equisetum Stem Anatomy T.S
     Vegetative Reproduction:  Fragmentation of rhizome, Tubers formed on rhizome
Strobilus or structure of cone
STROBILUS OF EQUISETUM

  •  Equisetum is homosporous and Eusporangiate
  •   Strobili are borne terminally and singly on aerial fertile branches.
  • Strobilus consists of a central axis on which stalked sporangiophores with sporangium are arranged in whorls
     Sporangiophore
·         Umbrella shaped structure with a slender stalk and a hexagonal peltate disc
·         The underside of peltate disc bears variable number of sac like sporangia
·         The number of sporangia in each sporangiophore may vary from 5-10
·         Sporangium consists of a 2 cell thick wall, with large number of homosporous spores.  Dehiscence along longitudinal slit. Spores are dispersed by  wind with the help of elaters
Spores and Elators
          Spores are Green, large, uninucleate, spherical, chloroplast containing structures with exine, intine and outermost epispore
          Elaters are spirally coiled , spoon shaped hygroscopic structures formed from epispore of haploid spore
          Each spore has 4 spirally arranged hygroscopic elaters
          Function: helps in dehiscence of sporangium and spore dispersal
Gametophyte or prothallus of Equisetum
Gametophyte or prothallus of Equisetum

  •     Spores falling on suitable substratum germinate to form green prothallus with rhizoids for fixation.
  •      Prothallus consists of a basal disc and number of green vertical lobes.
  •       Monoecious or bisexual: both antheridia and archegonia are present.
  •      Antheridia may occur on vertical lobes or basal disc embedded.
  •       Antheridium produces 256-512multiflagellate, spirally coiled spermatozoids.
  •      Archegonia flask shaped structures at the base of vertical lobes.
  •       Fusion forms embryo which give rise to new plant.
     Life cycle: Homomorphic alternation of generation
Life cycle of Equisetum
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Equisetum Stem Anatomy T.S

Equisetum morphology
Equisetum Stem Anatomy

·         Epidermis is single layered with stomata and heavily coated with silica deposits
·         Outer cortex is sclerenchymatous and chlorenchymatous
·         Often sclerenchaymatous below ridges followed by chlorenchymatous region
·         Inner cortex is made up of large parenchymatous cells with vallecular canals.
·         Vallecular canals are large air filled, intercellular spaces below the furrows in inner cortex
·         It is a hydrophytic character
·         Endodermis and pericycle single layered
·         Stele: Eustele, siphonostele; ring of vascular bundles below the ridges.
·         Vascular bundle is conjoint, collateral and closed and separated from one another by parenchyma
·         V.B consists of xylem, phloem and carinal canal
·         Xylem is poorly developed.
·         Carinal canal is a water filled region present in the vascular bundle.
·         Formed by the disintegration of protoxylem tracheids

·         Pith: Large central cavity filled with water (hydrophytic character)
Equisetum morphology
Equisetum Stem Anatomy

·         Epidermis is single layered with stomata and heavily coated with silica deposits
·         Outer cortex is sclerenchymatous and chlorenchymatous
·         Often sclerenchaymatous below ridges followed by chlorenchymatous region
·         Inner cortex is made up of large parenchymatous cells with vallecular canals.
·         Vallecular canals are large air filled, intercellular spaces below the furrows in inner cortex
·         It is a hydrophytic character
·         Endodermis and pericycle single layered
·         Stele: Eustele, siphonostele; ring of vascular bundles below the ridges.
·         Vascular bundle is conjoint, collateral and closed and separated from one another by parenchyma
·         V.B consists of xylem, phloem and carinal canal
·         Xylem is poorly developed.
·         Carinal canal is a water filled region present in the vascular bundle.
·         Formed by the disintegration of protoxylem tracheids

·         Pith: Large central cavity filled with water (hydrophytic character)
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Complex Tissues in Plants - Xylem and Phloem

A tissue made up of more than one type of cells functioning as a unit is called complex tissue. The vascular tissues as known as complex tissues. Xylem and Phloem are together called conducting tissues (vascular tissues) and are organised into vascular bundles. 
Types of Complex Tissues: Xylem and Phloem
Complex tissues in plants
Refer: Difference between Xylem and Phloem
A tissue made up of more than one type of cells functioning as a unit is called complex tissue. The vascular tissues as known as complex tissues. Xylem and Phloem are together called conducting tissues (vascular tissues) and are organised into vascular bundles. 
Types of Complex Tissues: Xylem and Phloem
Complex tissues in plants
Refer: Difference between Xylem and Phloem
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