PLANT KINGDOM

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PLANT KINGDOM
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CONTENTS

• SYSTEMS OF CLASSIFICATION
• CLASSIFICATION OF PLANTS
• ALGAE
• BRYOPHYTES
• MOSSES
• PTERIDOPHYTES
• GYMNOSPERMS
• ANGIOSPERMS
• PLANT LIFE CYCLES ALTERNATION OF GENERATIONS

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SYSTEMS OF CLASSIFICATION

• ARTIFICIAL NATURAL PHYLOGENETIC
• PHENETIC
• NUMERICAL CYTOTAXONOMY CHEMOTAXONOMY
• TAXONOMY

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ARTIFICIAL CLASSIFICATION

• Artificial classification is the system of
  classification which uses only gross superficial
  morphological characters such as habit, colour
  and shape of leaves etc. They were based mainly
  on vegetative characters or on the androecium
  structure.
• DRAWBACKS
• They separated the closely related species since
  they were based on a few characteristics.
• They gave equal weightage to vegetative and
  sexual characteristics.

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NATURAL CLASSIFICATION

• Natural classification systems were based on
  natural affinities among the organisms and
  consider, not only the external features, but
  also internal features, like ultra-structure,
  anatomy, embryology and phytochemistry. This
  classification for flowering plants was given by
  George Bentham and Joseph Dalton Hooker.

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PHYLOGENETIC CLASSIFICATION

• The phylogenetic classification systems were
  based on evolutionary relationships between the
  various organisms. This assumes that organisms
  belonging to the same taxa have a common
  ancestor. At present, this is acceptable.

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PHENETIC CLASSIFICATION

• NUMERICAL TAXONOMY
• Numerical taxonomy is carried out using
  computers is based on all observable
  characteristics.Numbers and codes are assigned to
  all the characters and the data are then
  processed.
• CYTOTAXONOMY
• Cytotaxonomy is based on cytological
  information like chromosome number, structure and
  behaviour.
• CHEMOTAXONOMY
• Chemotaxonomy uses the chemical constituents
  of the plant to resolve confusions.

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CLASSIFICATION OF PLANTS
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ALGAE

• Characteristics
• Chlorophyll bearing, thalloid, autotrophic
  organisms.
• Occur in fresh water as well as marine habitats.
• May be of variable shapes ranging from
  microscopic unicellular forms to filamentous
  forms.
• Laurencia, a marine red
  alga

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• Reproduce vegetatively by fragmentation,
  asexually by spore formation which may be
  zoospores or aplanospores.
• Sexual reproduction takes place by the fusion of
  gametes which may be isogamous, anisogamous or
  oogamous.

ISOGAMOUS- Fusion of two similar gametes, e.g.Spirogyra. ANISOGAMOUS- Fusion of two dissimilar gametes,e.g.Chlamydomonas. OOGAMOUS- Fusion between one large,non-motile female gamete and a smaller,motile male gamete,e.g.Volvox,Fucus.
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USES OF ALGAE

• Half of the total CO2 fixation
• on earth is carried out by algae
• through photosynthesis. Seaweed is
  used as a fertilizer
• They are primary producers of energy-rich
  compounds.
• Large number of marine algae are used as food
  ,e.g. Porphyra,Laminaria,Sargassum.
• Agar, obtained from Gelidium and Gracilaria are
  used to grow microbes and in preparations of
  ice-creams and jellies.
• 
  
  

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Divisions of Algae and their Main Characteristics
Classes Common Name Major Pigments Stored Food Cell Wall Flagellar Number and Positions of Insertions Habitat (Water)
Chlorophyceae Green Algae Chlorophyll a, b Starch Cellulose 2-8,equal, apical Fresh,brackish,salt
Phaeophyceae Brown Algae Chlorophyll a, c, fucoxanthin Mannitol, laminarin Cellulose, algin 2,unequal, lateral Fresh(rare),brackish, salt
Rhodophyceae Red Algae Chlorophyll a, d, phycoerythrin Floridean starch Cellulose Absent Fresh(some),brackish,salt(most)
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BRYOPHYTES

• Bryophytes are the amphibians of the plant
  kingdom.
• The plant body is a gametophyte, green,flat and
  dichotomously branched. It is the dominant phase
  in the life cycle.
• They lack the vascular and supporting tissues.
• The plant body is not differentiated into
  roots,stems and leaves.It is thalloid in Riccia
  and is differentiated into rhizoidstem(axis) and
  leaves in mosses.

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• The sex organs of the plant are antheridia (male)
  and archegonium (female).
• Male gametes(antherozoids) are motile and
  archegonium is flask shaped having venter and a
  long neck.
• Presence of water is necessary for fertilization.
• The zygote develops into a sporophyte which is
  dependent on the gametophyte completely or
  partially for its nutrition.
• Examples Liverwort- Marchantia
• Mosses- Funaria, Sphagnum

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USES OF BRYOPHYTES

• They help in the prevention of soil erosion.
• They build up soil on rocks with the help of
  lichens.
• They contribute to the organic matter in the soil
  on their death and decay.
• The Sphagnum, moss has remarkable water-absorbing
  capacity and is utilised by flourists and
  horticulturist.
• It is also used in surgical dressings.

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LIFE CYCLE OF MOSS

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PTERIDOPHYTES

• Found in cool, damp and shady places.
• Posses vascular bundles.
• Main plant body sporophytic differentiated into
  true root,stem and leaf-like structures.
• Leaves may be small or large known as microphylls
  and megaphylls respectively.
• Sporangia subtended in leaf-like appendages
  called as sporophyll bearing strobili or cones.
  The cones produce spores germinating into
  gametophytes called prothallus.

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• The spores may be similar in size- homosporous or
  dissimilar in size-heterosporous.
• The megaspores germinate to female gametophytes
  producing female gametes and the microspores
  germinate to male gametophyte producing male
  gametes.
• Zygote is formed as a result of fusion of the two
  gametes leading to development of embryo and then
  the sporophyte.
• The sporophyte phase is diploid and the
  gametophytic phase is haploid.

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• The pteridophytes are classified into four
  classes
• 1.Psilopsida(Psilotum)
• 2.Lycopsida(Selaginella,
• Lycopodium)
• 3.Sphenopsida(Equisetum)
• 4.Pteropsida(Dryopteris,
• Pteris,Adiantum) Lady fern
  (Athyrium filix-femina)

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Life cycle of Pteridophyte (fern)

• Young sporophyte
  Sporophylls
• (2N) (2N)
• Zygote(2N)
  Sori
• 
  (2N)
• Egg(N)
  Sporangium
• Antherozoids(N)
  (2N)
• Archegonium(N)
• Antheridium
  GerminationSpores Meiosis Spore
  
• 
  mother cells(2N)

FERN
SPOROPHYTIC GENERATION
GAMETOPHYTIC GENERATION
Prothallus
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GYMNOSPERM

• They are tiny group of tall plants with naked
  seeds.
• Grow in cool as well warm climate, in hills as
  well as plains.
• Plant body is sporophytic. The stems are erect,
  branched or unbranched.
• Plants produce cones or strobili.
• Plants are heterosporous producing micro and
  megaspores.
• The megaspore is enclosed within the
  mega-sporangium where it germinates to form
  female gametophyte.

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• In phloem, sieve cells are without companion
  cells and xylem lacks vessels.
• Pollination is carried by wind. Polyembryony is
  of common occurrence.
• ExamplesPinus, Cycas and Ginkgo.
• 
  White Spruce leaves
  (needles)
•   Coast Douglas-fir cone

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LIFE CYCLE OF GYMNOSPERM (PINUS)

• GERMINATION PINUS
  CONE(male)
• (EPIGEAL) (2n)
  CONE(female)
• SEED
  MEGASPOROPHYLLS
• 
  
  MICROSPOROPHYLLS
• EMBRYO DIPLOID PHASE MEGASPORANGIUM
• 
  (OVULE)
  MICROSPORANGIUM
• 
  
  (POLLEN SAC)
• 
  NUCELLUS
• OOSPORE(2n)
  
• 
  MEGASPORE MICROSPORE
• SPOROPHYTIC(2n) MOTHER
  CELLS MOTHER CELLS
• GAMETOPHYTE(N)
  MEIOSIS
• HAPLOID PHASE
  MEGASPORE(N) MICROSPORES(N)
• 
  (EMBRYO SAC CELL) (POLLEN GRAINS)
  
• FERTILIZATION
  POLLINATION
• 
  FEMALE GAMETOPHYTE MALE
• 
  (ENDOSPERM)
  GAMETOPHYTE

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ANGIOSPERM

• They are the flowering plants where seeds are
  enclosed within the ovary.
• The pollen grains(male gametes) and egg
  cell(female gamete)develop within the flower.
• The pollen grains are carried to the stigma of
  the ovary by various pollen agencies and thereon,
  it starts its development.
• The embryo sac within the ovary is an eight
  celled structure.

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• All angiosperm undergo fertilization. It protects
  the endosperm from being wasted away.
• Xylem is made up of tracheids, vessels, wood
  fibres and wood parenchyma whereas phloem
  consists of sieve tubes, companion cells
  phloem parenchyma.
• Two sub classes of angiosperms
  are Dicotyledons and
• Monocotyledons. A monocot (left),
  and dicot

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LIFE CYCLE OF AN ANGIOSPERM

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PLANT LIFE CYCLES AND ALTERNATION OF GENERATIONS

• Life cycles of plants has two distinct
• phases the diploid sporophytic the
• haploid gametophytic that alternate with
• each other. This phenomenon is called
• alternation of generation.

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HAPLONTIC LIFE CYCLE

• It is found in algae like Chlamydomonas,
• Ulothrix, Spirogyra, Oedogonium and
• Chara.

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DIPLONTIC LIFE CYCLE

• It is found in all seed bearing plants i.e.
• gymnosperms and angiosperms.

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HAPLO-DIPLONTIC LIFE CYCLE

• It is found typically in algae like Ectocarpus,
• Polysiphonia, bryophytes, pteridophytes etc.

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PRESENTED BY-

• SWATI KUMARI
• Class-XI Sc
• K V IOC, Noonmati
• Session 2007-08

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THANK YOU

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