PLANT KINGDOM
Whittaker classified the whole living organism into five kingdoms based on the complexity of cell structure
(Prokaryotic and Eukaryotic), complexity of body (unicellular and multicellular) and mode of nutrition
(autotrophs and heterotrophs).
Classification of plant kingdom:
All the classification system, starting from that of Aristotle to the 20th century, can be divided into three types-
Artificial, Natural and Phylogenetic.
• 1. Artificial system: Classification based on few morphological characters.
Theophrastus, Pliny and Linnaeus used artificial system of classification.
• 2. Natural system: Classification based on all the important related characters.
Both external and internal.
Bentham and hooker, Adanson, Candolle used natural system of classification.
• 3. Phylogenetic system: Classification based on evolutionary relationship of plants.
Eichler, Blessy, Whittaker, Engler and Prantl, Hutchinson used phylogeny.
Numerical taxonomy: Taxonomy based on statistical methods with equal importance using computer.
Cytotaxonomy: Taxonomy based on cytology or cell structure (chromosome number, shape, behaviour etc).
Chemotaxonomy: Taxonomy based on chemical constituents of plants (nature of protein, DNA sequence,
taste, smell etc).
EICHLERS CLASSIFICATION: Classification of Plant kingdom based on flowering.
Divided into two-Cryptogamae (non flowering, seedless plants) and Phanerogamae (flowering, seed bearing
plants).
Based on plant body Cryptogamae divided into Thallophyta, Bryophyta and Pteridophyta.
Thallophyta: Plant body is thallus like (undifferentiated plant body)
Bryophyta: plant body with root like structure, stem like structure, vascular tissues are absent).
Pteridophyta: Plant body is differentiated into true root, stem and leaves. Vascular tissues are present so
called vascular cryptogams.
Thallophytes again divided into
• 1. Algae (pigmented thallophytes)
• 2. Fungi (nonpigmented thallophytes)
• 3. Lichens: Symbiotic association between algae and fungi.
Phanerogamae divided into two
• 1. Gymonosperma (naked seed plants) and
• 2. Angiosperma (covered seeded plants)
Angiosperms are again divided into two
• 1.Monocots (have single cotyledon, fibrous root system and parallel venation)
• 2. Dicots (have two cotyledons, tap root system and reticulate venation).
Pteridophytes, Gymnosperms and Angiosperms are called Tracheophytes due to the presence of vascular
tissue.
Bryophyta, Pteridophyta, Gymnosperms and Angiosperms are called Embryophyta as they have embryo.
3.1 ALGAE:
Phycology: Branch of Biology which deals with the study of algae
,Phycos=sea weed
Logos=study
Fritch –Father of phycology.
M.O.P.Iyengar is the father of Indian phycology.
Algal members are pigmented thallophytes.
Habitat:
Hydrophytes: Water is their habitat
Xerophytes: In desert habitat
Mesophytes- in medium habitat
Epiphytes-on plants
Lithophytes- on rocks
Halophytes- in salty areas.
In aquatic habitat-fresh water (Spirogyra) and marine (Sargassum).
Floating- Chlamydomonas, Spirogyra
Benthophytes - (attached to the bottom) –Chara (stone worts)
Epiphyte-growing on plant body (Cladophora)
Epizoic-growing on animal body (Trichophillus)
Moist soil-terrestrials (Fritschiella).
Plant body:
The vegetative plant body is a haploid gametophyte.
Unicellular, flagellated (Chlamydomonas) or non-flagellated (Chlorella)
Multicellular:
a) Coenobium-a colony with fixed number of cells and division of labour. Eg: Volvox
b) Aggregation-indefinite colony. Eg: Tetraspora
c) Filamentous-unbranched .Eg: Ulothrix
d) Filamentous branched. Eg: Cladophora
e) Siphonous- multinucleate. Eg: Vaucheria
f) Parenchymatous. Eg: Ulva
g) Branched like higher plants. Eg: Sargassum, Chara
Nutrition:
Autotrophs - Photosynthetic (most of them)
Parasitic forms (rare). Eg: Cephaleuros.
Pigments:
• 1. Chlorophyll- a, b, c, d.
, • 2. Carotenoids- carotene and xanthophyll-fucoxanthin (dominating pigment in brown algae).
• 3. Phycobillins- phycocyanin and phycoerythrin.
Reproduction:
Vegetative reproduction- Reproduction using the vegetative parts.
Different types are
• Fission
• Fragmentation
• Budding
• Tubers
• Gemmae.
Asexual reproduction-without the fusion of gametes.
Mainly by:
• Zoospores within sporangia
• Aplanospores
• Akinete
• Hypnospores
• Endospore
• Exospore
• Monospore
• Auxospore.
Palmella stage-spores become colonial and appear like the algae named Palmella.
Eg: Ulothrix, Chlamydomonas.
Sexual reproduction:
Homogametes-similar gametes
Heterogametes-dissimilar gametes
• Isogamy: fusion of morphologically and physiologically similar gametes.
Isogamy- flagellated (Chlamydomonas ) and nonflagellated (Spirogyra).
• Anisogamy: fusion of morphologically or physiologically dissimilar gametes.
Morphologically dissimilar–eg: Chlamydomonas
Physiologically dissimilar –eg: Spirogyra.
• Oogamy- fusion of morphologically and physiologically dissimilar gametes.
Small motile male gamete + large nonmotile female gamete.
Eg: Fucus, Volvox.
Exceptional cases:
Whittaker classified the whole living organism into five kingdoms based on the complexity of cell structure
(Prokaryotic and Eukaryotic), complexity of body (unicellular and multicellular) and mode of nutrition
(autotrophs and heterotrophs).
Classification of plant kingdom:
All the classification system, starting from that of Aristotle to the 20th century, can be divided into three types-
Artificial, Natural and Phylogenetic.
• 1. Artificial system: Classification based on few morphological characters.
Theophrastus, Pliny and Linnaeus used artificial system of classification.
• 2. Natural system: Classification based on all the important related characters.
Both external and internal.
Bentham and hooker, Adanson, Candolle used natural system of classification.
• 3. Phylogenetic system: Classification based on evolutionary relationship of plants.
Eichler, Blessy, Whittaker, Engler and Prantl, Hutchinson used phylogeny.
Numerical taxonomy: Taxonomy based on statistical methods with equal importance using computer.
Cytotaxonomy: Taxonomy based on cytology or cell structure (chromosome number, shape, behaviour etc).
Chemotaxonomy: Taxonomy based on chemical constituents of plants (nature of protein, DNA sequence,
taste, smell etc).
EICHLERS CLASSIFICATION: Classification of Plant kingdom based on flowering.
Divided into two-Cryptogamae (non flowering, seedless plants) and Phanerogamae (flowering, seed bearing
plants).
Based on plant body Cryptogamae divided into Thallophyta, Bryophyta and Pteridophyta.
Thallophyta: Plant body is thallus like (undifferentiated plant body)
Bryophyta: plant body with root like structure, stem like structure, vascular tissues are absent).
Pteridophyta: Plant body is differentiated into true root, stem and leaves. Vascular tissues are present so
called vascular cryptogams.
Thallophytes again divided into
• 1. Algae (pigmented thallophytes)
• 2. Fungi (nonpigmented thallophytes)
• 3. Lichens: Symbiotic association between algae and fungi.
Phanerogamae divided into two
• 1. Gymonosperma (naked seed plants) and
• 2. Angiosperma (covered seeded plants)
Angiosperms are again divided into two
• 1.Monocots (have single cotyledon, fibrous root system and parallel venation)
• 2. Dicots (have two cotyledons, tap root system and reticulate venation).
Pteridophytes, Gymnosperms and Angiosperms are called Tracheophytes due to the presence of vascular
tissue.
Bryophyta, Pteridophyta, Gymnosperms and Angiosperms are called Embryophyta as they have embryo.
3.1 ALGAE:
Phycology: Branch of Biology which deals with the study of algae
,Phycos=sea weed
Logos=study
Fritch –Father of phycology.
M.O.P.Iyengar is the father of Indian phycology.
Algal members are pigmented thallophytes.
Habitat:
Hydrophytes: Water is their habitat
Xerophytes: In desert habitat
Mesophytes- in medium habitat
Epiphytes-on plants
Lithophytes- on rocks
Halophytes- in salty areas.
In aquatic habitat-fresh water (Spirogyra) and marine (Sargassum).
Floating- Chlamydomonas, Spirogyra
Benthophytes - (attached to the bottom) –Chara (stone worts)
Epiphyte-growing on plant body (Cladophora)
Epizoic-growing on animal body (Trichophillus)
Moist soil-terrestrials (Fritschiella).
Plant body:
The vegetative plant body is a haploid gametophyte.
Unicellular, flagellated (Chlamydomonas) or non-flagellated (Chlorella)
Multicellular:
a) Coenobium-a colony with fixed number of cells and division of labour. Eg: Volvox
b) Aggregation-indefinite colony. Eg: Tetraspora
c) Filamentous-unbranched .Eg: Ulothrix
d) Filamentous branched. Eg: Cladophora
e) Siphonous- multinucleate. Eg: Vaucheria
f) Parenchymatous. Eg: Ulva
g) Branched like higher plants. Eg: Sargassum, Chara
Nutrition:
Autotrophs - Photosynthetic (most of them)
Parasitic forms (rare). Eg: Cephaleuros.
Pigments:
• 1. Chlorophyll- a, b, c, d.
, • 2. Carotenoids- carotene and xanthophyll-fucoxanthin (dominating pigment in brown algae).
• 3. Phycobillins- phycocyanin and phycoerythrin.
Reproduction:
Vegetative reproduction- Reproduction using the vegetative parts.
Different types are
• Fission
• Fragmentation
• Budding
• Tubers
• Gemmae.
Asexual reproduction-without the fusion of gametes.
Mainly by:
• Zoospores within sporangia
• Aplanospores
• Akinete
• Hypnospores
• Endospore
• Exospore
• Monospore
• Auxospore.
Palmella stage-spores become colonial and appear like the algae named Palmella.
Eg: Ulothrix, Chlamydomonas.
Sexual reproduction:
Homogametes-similar gametes
Heterogametes-dissimilar gametes
• Isogamy: fusion of morphologically and physiologically similar gametes.
Isogamy- flagellated (Chlamydomonas ) and nonflagellated (Spirogyra).
• Anisogamy: fusion of morphologically or physiologically dissimilar gametes.
Morphologically dissimilar–eg: Chlamydomonas
Physiologically dissimilar –eg: Spirogyra.
• Oogamy- fusion of morphologically and physiologically dissimilar gametes.
Small motile male gamete + large nonmotile female gamete.
Eg: Fucus, Volvox.
Exceptional cases:
