Difference between Osmotic pressure and Osmotic potential

Osmosis  Osmotic pressure and Osmotic potential

The movement of water molecules through a semi permeable membrane from the region of higher water concentration to the region of lesser water concentration is called osmosis.
Osmotic Pressure (OP): The actual pressure, that develops in a solution, when it is separated from pure water by means of semipermeable membrane. It depends upon concentration, ionization, hydration and temperature. It is measured in terms of atmosphere (atm).
OP=miRT
where, m= Molar concentration, i= ionization constant,
 R= Gas constant and T= temperature.
Osmotic potential: It is the decrease in chemical potential of pure water due to the presence of solute particle in it.
  ψs= CRT
 (It always have negative value)
Where C = concentration of solute particle, R = gas constant and T= temperature.
Osmotic pressure vs Osmotic potential
Osmotic pressure:
1. It is the pressure which develops in an osmotic system due to entry of water into it.
2. It develops only in a confirmed system.
3. The value is positive through numerically eual to osmotic potential.

Osmotic potential:
1. It is lowering of free energy of water in a system duet o the presence of solute particles.
2. Osmotic potential is present whether the solution occurs in a confined system or an open system.
3.The value is negative through it is numerically equal  to osmotic pressure.
Learn more: Difference between Osmosis and Diffusion (Osmosis vs Diffusion)
Osmosis  Osmotic pressure and Osmotic potential

The movement of water molecules through a semi permeable membrane from the region of higher water concentration to the region of lesser water concentration is called osmosis.
Osmotic Pressure (OP): The actual pressure, that develops in a solution, when it is separated from pure water by means of semipermeable membrane. It depends upon concentration, ionization, hydration and temperature. It is measured in terms of atmosphere (atm).
OP=miRT
where, m= Molar concentration, i= ionization constant,
 R= Gas constant and T= temperature.
Osmotic potential: It is the decrease in chemical potential of pure water due to the presence of solute particle in it.
  ψs= CRT
 (It always have negative value)
Where C = concentration of solute particle, R = gas constant and T= temperature.
Osmotic pressure vs Osmotic potential
Osmotic pressure:
1. It is the pressure which develops in an osmotic system due to entry of water into it.
2. It develops only in a confirmed system.
3. The value is positive through numerically eual to osmotic potential.

Osmotic potential:
1. It is lowering of free energy of water in a system duet o the presence of solute particles.
2. Osmotic potential is present whether the solution occurs in a confined system or an open system.
3.The value is negative through it is numerically equal  to osmotic pressure.
Learn more: Difference between Osmosis and Diffusion (Osmosis vs Diffusion)
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The Taxonomic Hierarchy of Plants (Mango)

Once you named an organism you have to assign an appropriate position in a systematic frame work of classification. This frame work is called taxonomic hierarchy by which the taxonomic groups are arranged in a definite order from higher to lower categories. Each category in the hierarchy is considered as a taxonomic unit and is known as taxon.
Taxonomic Hierarchy - Mango
The categories used in the classification of plants are kingdom, division, class, order, family, genus and species.
Taxonomic Hierarchy of Mango (Taxonomic Position of Mango)
Kingdom - Plantae
Division - Embryophyta or Angiospermae
Class- Dicotyledonae
Order - Sapindales
Family- Anacardiaceae
Genus- Mangifera
Species- indica
 In the case of animals instead of division, phylum is used. These categories are ranked on above the other, called hierarchyKingdom is the highest and species is the lowest category in this hierarchy.
ICBN (International Code of Botanical Nomenclature) recognizes 12 main ranks: Kingdom, Class, Order, Family, Tribe, Genus, Section, Series, Species, Varieties and Form with adequate provision for designing sub categories below each rank (sub division, sub  class, sub genus, sub species, sub variety etc).
Once you named an organism you have to assign an appropriate position in a systematic frame work of classification. This frame work is called taxonomic hierarchy by which the taxonomic groups are arranged in a definite order from higher to lower categories. Each category in the hierarchy is considered as a taxonomic unit and is known as taxon.
Taxonomic Hierarchy - Mango
The categories used in the classification of plants are kingdom, division, class, order, family, genus and species.
Taxonomic Hierarchy of Mango (Taxonomic Position of Mango)
Kingdom - Plantae
Division - Embryophyta or Angiospermae
Class- Dicotyledonae
Order - Sapindales
Family- Anacardiaceae
Genus- Mangifera
Species- indica
 In the case of animals instead of division, phylum is used. These categories are ranked on above the other, called hierarchyKingdom is the highest and species is the lowest category in this hierarchy.
ICBN (International Code of Botanical Nomenclature) recognizes 12 main ranks: Kingdom, Class, Order, Family, Tribe, Genus, Section, Series, Species, Varieties and Form with adequate provision for designing sub categories below each rank (sub division, sub  class, sub genus, sub species, sub variety etc).
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Short notes on Binomial System of Nomenclature

  • Binomial system of nomenclature was introduced by Casper Bauhin (Gaspard Bauhin) in 1596.
Who proposed binomial system of nomenclature?
  • Later, it was developed by Swedish botanists Carolus Linnaeus (Father of taxonomy) in his book Species Plantarum (1753).
Definition binomial system?
  • An internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species.
How do we write binomial system of nomenclature?
  • According to this system, each plant (any organism) is given a name made of two Latin  wards.
  • The first word represent the genus and is called generic name or generic epithet, where as the second word represents species and is called specific name or specific epithet.
Binomial System of Nomenclature
Example of Scientific names
Human – Homo sapiens (here., Homo - genus name, sapiens- species name)
    Coffee – Coffee arabica
      Mango – Mangifera indica
        Potato – Potato tuberosum
        • The generic name or epithet always stats with capital letter and specific epithet starts with small letter.
                  Potato – Potato tuberosum 
        • Both these names are underlined separately. If printed italicized separately.
        Learn more: 
        • Binomial system of nomenclature was introduced by Casper Bauhin (Gaspard Bauhin) in 1596.
        Who proposed binomial system of nomenclature?
        • Later, it was developed by Swedish botanists Carolus Linnaeus (Father of taxonomy) in his book Species Plantarum (1753).
        Definition binomial system?
        • An internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species.
        How do we write binomial system of nomenclature?
        • According to this system, each plant (any organism) is given a name made of two Latin  wards.
        • The first word represent the genus and is called generic name or generic epithet, where as the second word represents species and is called specific name or specific epithet.
        Binomial System of Nomenclature
        Example of Scientific names
        Human – Homo sapiens (here., Homo - genus name, sapiens- species name)
          Coffee – Coffee arabica
            Mango – Mangifera indica
              Potato – Potato tuberosum
              • The generic name or epithet always stats with capital letter and specific epithet starts with small letter.
                        Potato – Potato tuberosum 
              • Both these names are underlined separately. If printed italicized separately.
              Learn more: 
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              Plant Images Euphorbia hirta (Euphorbiaceae)

              Euphorbia hirta
               Scientific NameEuphorbia hirta L. Family : Euphorbiaceae


              Vegetative characters
              Habit: Herb

              Leaves:  Simple, elliptical, hairy (on both upper and lower surfaces but particularly on the veins on the lower leaf surface), with a finely dentate margin. Occur in opposite pairs on the stem.

              Flowers/inflorescenceUnisexual and found in axillary cymes at each leaf node. Typically cyathium. 

              Fruit: Capsules

              UsesFor treating Asthma, bronchitis, Coughs, Hay fever, Tumors, Digestive problems, Intestinal worms, Gonorrhea.
              Euphorbia hirta
               Scientific NameEuphorbia hirta L. Family : Euphorbiaceae


              Vegetative characters
              Habit: Herb

              Leaves:  Simple, elliptical, hairy (on both upper and lower surfaces but particularly on the veins on the lower leaf surface), with a finely dentate margin. Occur in opposite pairs on the stem.

              Flowers/inflorescenceUnisexual and found in axillary cymes at each leaf node. Typically cyathium. 

              Fruit: Capsules

              UsesFor treating Asthma, bronchitis, Coughs, Hay fever, Tumors, Digestive problems, Intestinal worms, Gonorrhea.
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              Difference between Photoactive and Scotoactive stomata

              Stomata are minute pores present on the surface of leaf and young stem. They are meant for the exchange of gases, also lose of water vapour, when open. The loss of water through stomata is called stomatal transpiration. Stomata are of different types
              Photoactive and Scotoactive stomata
              Photoactive vs Scotoactive stomata
              Photoactive stomata (Photo means light): The stomata opening in response to the presence of light are called photoactive stomata
              1. These stomata remain open during day time.
              2. Found in all ordinary plants.

              Scotoactive stomata (Scoto means dark): The  stomata opening in dark are called scotoactive stomata.
              1. Stomata remain open during night.
              2. Found in some plants like Bryophyllum
              Stomata are minute pores present on the surface of leaf and young stem. They are meant for the exchange of gases, also lose of water vapour, when open. The loss of water through stomata is called stomatal transpiration. Stomata are of different types
              Photoactive and Scotoactive stomata
              Photoactive vs Scotoactive stomata
              Photoactive stomata (Photo means light): The stomata opening in response to the presence of light are called photoactive stomata
              1. These stomata remain open during day time.
              2. Found in all ordinary plants.

              Scotoactive stomata (Scoto means dark): The  stomata opening in dark are called scotoactive stomata.
              1. Stomata remain open during night.
              2. Found in some plants like Bryophyllum
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              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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