3. Plant Kingdom
POINTS TO REMEMBER :
CLASSIFICATION :
Artificial System of Classification :
• Used superficial morphological characters.
• Based on a few characteristics like habit, colors, number and shape of leaf.
• Mainly based on vegetative characters.
• Such system developed by Linnaeus.
Natural System of Classification :
• Based on natural affinities among organisms
• Included external as well as internal features like anatomy, embryology and phytochemistry.
• Developed by George Bentham and J. D. Hooker
Phylogenetic System of Classification :
• Based on evolutionary relationships between the various organisms.
• Organism belongs to same taxa have a common ancestors.
• Developed by Hutchinson.
Numerical Taxonomy :
• Carried out using computers
• Based on all observable characteristics
• Data processed after assigning number and codes to all the characters.
Cytotaxonomy :
• Based on cytological information.
• Gives importance to chromosome number, structure and behaviour.
Chemotaxonomy :
• Based on chemical constituents of the plants.
ALGAE :
• Chlorophyll bearing, simple, thalloid, autotrophic and mostly aquatic organisms. Moist stone, soils and wood are the
other habitat.
• The size ranges from microscopic unicellular forms like Chlamydomonas, to colonial forms like Volvox and to
filamentous forms like Ulothrix and Spirogyra. A few marine forms such as kelps, form massive plant bodies.
• Reproduce vegetatively by fragmentation.
• Reproduce asexually mostly by producing motile spore called zoospores.
• Reproduce sexually by producing gametes.
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, • Isogamous: both gametes are same size and motile
• Anisogamous: both gametes are dissimilar in size but motile.
• Oogamous: male gamete is smaller but motile, female gamete is large and non- motile.
Importance of Algae :
• At least half of the total carbon dioxide fixation on earth carried out by them.
• Increase oxygen level in the environment.
• Many species like Laminaria, Sargassum etc. are used as food.
• Agar obtained from Gelidium and Gracilaria is used in ice-creams and jellies and also used to culture bacteria.
• Algin obtained from brown algae and carrageen from red algae used commercially.
• Chlorella and Spirullina are unicellular algae, rich in protein and used as food supplement even by space travelers.
Algae divided into 3 classes :
Chlorophyceae :
• Commonly known as Green algae.
• Main pigment is chlorophyll ‘a’ and ‘b’.
• Unicellular, colonial or filamentous.
• Cell wall has inner layer of cellulose and outer layer of pectose.
• Have pyrenoid as the storage body for starch and proteins.
e.g., Chlamydomonas, Volvox, Spirogyra.
Phaeophyceae :
• Commonly known as Brown algae and mainly found in marine habitat.
• They possess chlorophyll a, c, carotenoid, xanthophylls and fucoxanthin.
• Cell wall has cellulose and lignin or gelatinous coating of algin.
• Has mannitol and laminarin as reserve food material.
• Body divisible into holdfast, stipe and frond.
• Reproduce asexually by biflagellate pear-shaped zoospores.
e.g., Ectocarpus, Fucus, Laminaria.
Rhodophyceae :
• Commonly known as red algae.
• Red color is due to predominance of red pigment r-phycoerythrin in their body along with chlorophyll a, d.
• Found on surface as well as great depths in oceans.
• Cell wall made of cellulose, pectin and polysulphate esters.
• Reserve food material is floridean starch similar to amylopectin and glycogen in structure.
• Reproduce asexually by non motile spores and sexually by non motile gametes (Oogamous type)
e.g., Polysiphonia, Porphyra, Gelidium.
BRYOPHYTES : Amphibians of plant kingdom
• Occur in damp, humid places.
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POINTS TO REMEMBER :
CLASSIFICATION :
Artificial System of Classification :
• Used superficial morphological characters.
• Based on a few characteristics like habit, colors, number and shape of leaf.
• Mainly based on vegetative characters.
• Such system developed by Linnaeus.
Natural System of Classification :
• Based on natural affinities among organisms
• Included external as well as internal features like anatomy, embryology and phytochemistry.
• Developed by George Bentham and J. D. Hooker
Phylogenetic System of Classification :
• Based on evolutionary relationships between the various organisms.
• Organism belongs to same taxa have a common ancestors.
• Developed by Hutchinson.
Numerical Taxonomy :
• Carried out using computers
• Based on all observable characteristics
• Data processed after assigning number and codes to all the characters.
Cytotaxonomy :
• Based on cytological information.
• Gives importance to chromosome number, structure and behaviour.
Chemotaxonomy :
• Based on chemical constituents of the plants.
ALGAE :
• Chlorophyll bearing, simple, thalloid, autotrophic and mostly aquatic organisms. Moist stone, soils and wood are the
other habitat.
• The size ranges from microscopic unicellular forms like Chlamydomonas, to colonial forms like Volvox and to
filamentous forms like Ulothrix and Spirogyra. A few marine forms such as kelps, form massive plant bodies.
• Reproduce vegetatively by fragmentation.
• Reproduce asexually mostly by producing motile spore called zoospores.
• Reproduce sexually by producing gametes.
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, • Isogamous: both gametes are same size and motile
• Anisogamous: both gametes are dissimilar in size but motile.
• Oogamous: male gamete is smaller but motile, female gamete is large and non- motile.
Importance of Algae :
• At least half of the total carbon dioxide fixation on earth carried out by them.
• Increase oxygen level in the environment.
• Many species like Laminaria, Sargassum etc. are used as food.
• Agar obtained from Gelidium and Gracilaria is used in ice-creams and jellies and also used to culture bacteria.
• Algin obtained from brown algae and carrageen from red algae used commercially.
• Chlorella and Spirullina are unicellular algae, rich in protein and used as food supplement even by space travelers.
Algae divided into 3 classes :
Chlorophyceae :
• Commonly known as Green algae.
• Main pigment is chlorophyll ‘a’ and ‘b’.
• Unicellular, colonial or filamentous.
• Cell wall has inner layer of cellulose and outer layer of pectose.
• Have pyrenoid as the storage body for starch and proteins.
e.g., Chlamydomonas, Volvox, Spirogyra.
Phaeophyceae :
• Commonly known as Brown algae and mainly found in marine habitat.
• They possess chlorophyll a, c, carotenoid, xanthophylls and fucoxanthin.
• Cell wall has cellulose and lignin or gelatinous coating of algin.
• Has mannitol and laminarin as reserve food material.
• Body divisible into holdfast, stipe and frond.
• Reproduce asexually by biflagellate pear-shaped zoospores.
e.g., Ectocarpus, Fucus, Laminaria.
Rhodophyceae :
• Commonly known as red algae.
• Red color is due to predominance of red pigment r-phycoerythrin in their body along with chlorophyll a, d.
• Found on surface as well as great depths in oceans.
• Cell wall made of cellulose, pectin and polysulphate esters.
• Reserve food material is floridean starch similar to amylopectin and glycogen in structure.
• Reproduce asexually by non motile spores and sexually by non motile gametes (Oogamous type)
e.g., Polysiphonia, Porphyra, Gelidium.
BRYOPHYTES : Amphibians of plant kingdom
• Occur in damp, humid places.
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