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Plant Kingdom chapter 3 class 11th


01

DEFINITION
Uses of algae
  • Algae are used as food as they are rich in carbohydrates, vitamins and few other inorganic substances. For example, Spirogyra is the chief source of food. 
  • Algae release lot of oxygen into water as a by-product of photosynthesis. This is the source of dissolved oxygen for aquatic organisms.
  • Agar Agar is used in preparation of ice-cream and jellies. For example, Gelidium.
  • Algae are chewed instead of tobacco. For example, Rhodomenia.
  • Algae are used extensively in industries to prepare some products like sugar, soap, cement, rubber blotting paper etc.
  • Algae are used in agriculture to increase soil fertility. For example, Nostoc, Anabena.
  • Some algae are used in the preparation of medicines.
02

DEFINITION
Algae
  • They are found in wet and damp places.
  • They are autotrophic.
  • Some of them are used as food.
  • For examples, diatoms.
03

DEFINITION
Algae from the pond water or water from tanks
  • Prepare a smear of green string like scraping from the pond collected from the pond on the slide and place a coverslip over it.
  • Observe under microscope.
  • The green string like structure are algae.
04

DEFINITION
Rhodophyta (red algae)
  • They have water soluble red pigment (phycoerythrin), which masks the green color of chlorophyll a.
  • The main storage product is floridean starch.
  • Sexual reproduction is advanced oogamous type. The male organ produces non motile gametes and the female organ has a long receptive neck. After sexual reproduction special spores are produced.
  • For example, Batrachospermum, Polysiphonia.
05

SHORTCUT
Phaeophyta (brown algae)
  • It contain brown carotenoid, fucoxanthin, which masks the green colour of chlorophyll pigment.
  • Most of them are marine.
  • The main storage product is laminarin.
  • Sexual reproduction ranges from isogamous to oogamous. Motile gametes have two laterally attached flagella. Varied types of alternation of generation.
  • For example, Ectocarpus, Sargassum.
06

DEFINITION
Chlorophyta (green algae)
  • It contains chlorophyll a and b, which impart them bright green colour.
  • The main stoarge product is starch and cellulosic cell wall.
  • Sexual reproduction ranges from isogamous to oogamous.
  • For example, Chlamydomonas, Volvox, Chlorella.
07

DEFINITION
Economic importance of Algae
  • Algae are used as food as they are rich in carbohydrates, vitamins and few other inorganic substances. For example, Spirogyra is the chief source of food. 
  • Algae release lot of oxygen into water as a by-product of photosynthesis. This is the source of dissolved oxygen for aquatic organisms.
  • Agar Agar is used in preparation of ice-cream and jellies. For example, Gelidium.
  • Algae are chewed instead of tobacco. For example, Rhodomenia.
  • Algae are used extensively in industries to prepare some products like sugar, soap, cement, rubber blotting paper etc.
  • Algae are used in agriculture to increase soil fertility. For example, Nostoc, Anabena.
  • Some algae are used in the preparation of medicines.
08

DEFINITION
Division Bryophyta
  • Primitive, multicellular, autotrophic, shade loving, amphibious plants.
  • Thin, soft, plate like green body (thallus) which is differentiated into stem and leaves or roots (rhizoids) like structures.
  • Vascular system absent
  • Reproduction: Spore formation
  • For example, Funaria, Marchantia, Riccia.
09

DEFINITION
Beneficial use of algae
  • Algae is used as a source of food in many countries.
  • Some of its products are used in industries. For example, agar agar, alginate, carrageenan.
  • It is used for the production of antibiotics and medicines.
10

DEFINITION
Reproduction in Pteridophyta
  • Reproduction in pteridophytes involves production of spores.
  • Spores are produced inside a special structure called sporangia which occur on the ventral surface of fertile leaves called as sporophylls. 
  • Sporangia may sometimes be found in groups called sori.
11

DEFINITION
Classification of Pteridophyta
1) Sub-Division - Psilopsida
  • These are the oldest known vascular plants. Most of them have become extinct (e.g., Rhynia, Horneophyton). Only two living species, Psilotum and Tmesipteris, are now available.
  • Plant body is very simple and does not show much differentiation.
  • Dichotomously branched rhizome takes the place of roots.
  • Sporangia are directly borne on the stem (i.e., cauline). Either terminal or lateral.
2) Subdivision Lycopsida
  • Plant body shows differentiation into root, stem and leaves.
  • Leaves are microphyllous (small) having a single unbranched vein in the midrib region.
  • Sporangia are borne in the axil of the fertile leaves.
  • Sporophyll form compact strobili (singular strobilus).
3) Subdivision Sphenopsida
  • Plant body shows differentiation into nodes and internodes like higher vascular plants.
  • Leaves microphyllous, and arise in whorls at each node.
  • Sporangia develop on sporangiophores which form compact cones at the apex of fertile branches (e.g., Equisetum).
4) Subdivision Pteropsida (Ferns)
  • Plant body shows much advancement towards higher vascular plants, and is well differentiated into root, stem and leaves.
  • Leaves also show great advancement, and are megaphyllous (large) and pinnately compound.
  • Sporangia develop on the ventral surface of the sporophylls, and usually aggregated into sori (e.g., Dryopteris, Pteris, Pteridium, Polypodium etc.)
12

DEFINITION
Division: Pteridophyta
  • Multicellular and autotrophic animals.
  • Body is differentiated into root, stem and leaves.
  • Vascular system present.
  • Reproduction is sexually through spores and asexually by formation of gametes.
  • For examples, Adiantum, Lycopodium, Marsilea, Selaginella.
13

DEFINITION
Equisetum
  • Habitat of Equisetinae is in moist place. Most of Equisetinae has internodes stems in branch. 
  • The leaves are small look like membrane and arranged bunches. 
  • Sporophyl are shield-shaped with amount of sporangium in the bottom. 
  • Sporangium is arranged conical-shape in tip of the stem or branch. Protalium are green and develop in the outer of their spores. 
  • For example, Equisetum debile, Sphenophyllum cuneifolium, and Hyenia elegans. 
14

DEFINITION
Subkingdom - Cryptogams
  • Non flowering plants, reproduce by formation of spores.
  • Include thallophytes, bryophytes and pteridophytes.
  • Hidden reproductive organs.
15

DEFINITION
Subkingdom - Phanerogamae
  • Flowering plants, plant body is well differentiated into root, stem and leaves.
  • Vascular system present.
  • Well developed reproductive tissues that make seeds.
  • Further classification is based on whether the seeds are naked (gymnosperms) or enclosed in a fruit (angiosperms).
16

DEFINITION
Division - Gymnosperms
  • Evergreen, perennial, have unbranched stem and conifer leaves.
  • Do not have an outer covering or shell around their seeds i.e., have naked seeds
  • Bear separate male and female flowers called as cones.
  • Do not produce fruits and flowers.
  • For example, Pinus, Cycas, Cedrus.
17

DEFINITION
Characteristics of Cycas
  • It is known as living fossil.
  • It has an unbranched columnar stem which is covered by spiral bands of persistent rhomboidal leaf.
  • Cycas plants are highly valued for their ornamental looks, and hence grown in homes and gardens as an ornamental plant.
18

DEFINITION
Division - Angiosperms
  • Bear flowers as reproductive organs, seeds develop inside fruit.
  • Plant embryos in seeds have structures called cotyledons (seed leaves).
  • Further classification is based on single cotyledons (monocotyledonous plants) or two cotyledons (dicotyledonous plants).
19

DEFINITION
Haplontic life cycle of a plant
  • It is characterized by dominant gametophyte and zygotic meiosis.  
  • The sporophyte generation is represented only by the one-celled zygote, sometimes called zygospore. 
  • The zygote undergoes meiosis to form haploid spores. 
  • Each spore germinates (divide mitotically) to form gametophyte. 
  • Haplontic life cycle found in many algae like Volvox, Spirogyra, Ulothrix, Chlamydomonasetc.
20

DEFINITION
Diplontic life cycle of a plant
  • The life cycle characterized by gametic meiosis and diploid sporophyte this is dominant, photosynthetic and independent generation of the plant. 
  • The gametophyte generation is represented by the haploid gametes or few celled haploid gametophyte. 
  • Diplontic life cycle is exhibited by some green algae, brown algae and all seed bearing plants i.e., gymnosperms and angiosperms. 
  • In seeded plants pollens and ovaries contain male and female gametophytes, respectively.
21

DEFINITION
Haplodiplontic life cycle of plant
  • This type of life cycle involves the alternation of two vegetative individuals, the haploid gametophyte and diploid sporophyte. 
  • In this case, sporogenic meiosis occurs in sporophyte to produce spores (meiospores). 
  • This type of life cycle is exhibited by some green algae, brown algae, bryophytes and pteridophytes.
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