NCERT Notes for Class 11 biology Chapter 3 Plant kingdom

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Numerical taxonomy

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based on several features compared collectively by computer.

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Cytotaxonomy

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based on cytological features.

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Chemotaxonomy

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based on chemical constituent.

Algae–

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Group of chlorophyllous, simple, thalloid plants.

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 Largely aquatic, grow on soil, stone, wood etc or symbiotic.

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Unicellular to large filamentous.

Chlorophyceae

Phaeophyceae

Rhodophyceae

• Green algae chlorophyll a&b dominant. Unicellular to filamentous.
• Chloroplast of different shape( cup, spiral, ribbon) with pyrenoids.
• Stored food starch.
• Reproduction
• vegetative
• fragmentation Asexual
  – by zoospores
  – Sexual
  – by gametes(iso,  aniso  and oogamus).
  – egVolvox, Ulothrix, Spirogyra, Chara etc.

-Brown algae.
– Xanthophyl, Fucoxanthin dominant others are chl. a, c cartenoid.
– Simple  branched  filamentous  to profusely branched large body.
– Gelatinous coating on cell wall.
– Stored food Mannitoland Laminarin.Reproduction
– Vegetative by fragmentation Asexual By biflagellate (lateral) zoospores.
Sexual by  gametes(Iso, Aniso  and Oogamy).
– eg. Laminaria,Sargassum.

–  phycoerythrin  (dominant)  and others chlorophyll a and d.
– Marine on surface or in great depths, multi cellular.
– Stored food
– Floridean starch.
-Red algae
– Reproduction
Vegetative by fragmentation Asexual by non motile spores Sexual by oogamy.
– eg. Gracilaria, Gelidium

Liverworts

Mosses

Thallus dorsiventrally flattened (Liver shaped), leafy members with leaf like appendages.
2. Asexual reproduction by fragmentation , gemmae formation.
3.Sexual reproduction – antheridia and archegonia produced.
4. Antherozoids fuse with egg to form zygote which give rise to Sporophyte.
5. Sporophyte – with foot, seta & capsule.
6. Spores give rise to new plant (gametophyte).
eg. Riccia, Marchantia etc.

Marchantia

– Thallus : Two stages (gametophyte) –
(a)  Thread  like  Protonema  (b)erect  Leafy stage.
1. Reproduction :Vegetative by Fragmentation of protonema
& Sexual by antherozoids &egg.
2. Zygote forms Sporophyte  with foot, seta

&capsule.
-Sporophyte forms spores which germinate to form protonema.
eg. Funaria, Polytrichum etc.

Funaria

Pteridophyte:

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Group of first terrestrial plants having vascular tissue viz. Xylem & Phloem.

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True stem, root & leaf.

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 Found on damp, shady places.  Sporophyte makes main plant body.

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Sporophylls of Sporophyte bear sporangia (sori) onventral side producing haploid spores.

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spores give rise to Prothallus which is leafy & autotrophic.

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Prothallus bears sex organs – male – Antheridium and female- Archegonium.

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Fertilisation leads into zygote formation which produces diploid Sporophyte.

Heterospory and Seed habit:

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Two types of spores Microspore and Megaspore are produced in some members viz. Selaginella, Salvinia.

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called Heterospory.

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Heterospory is considered as begining of seed habit in terrestrial plants.

eg. Pteris, Dryopteris etc.

GYMNOSPERMS

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Medium sized trees and shrubs.

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Main plant body Sporophyte

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In some members roots may have fungal association called Mycorrhiza.

-bilus.

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Microspore i.e. pollens reaches to ovules.Pollen tubes help to transfer male gametes up to egg of archegonia present in female gametophyte of ovule.

Zygote develops in an embryo inside seed

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e.g. Cycas, Pinus ,Cedrusetc.

ANGIOSPERMS

Large no. of plants in varied habitats, small microscopic plants (Wolfia) to large trees

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 Group of plants having covered seeds in fruits.

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Produce flowers having reproductive organs.

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Most evolved plants.

Haplontic

Diplontic

Haplodiplontic

–  Dominating  phase haploid (n).
-only zygote diploid (2n).
-Haploid   spores   form   the main plant bodyeg.      Algae      viz.          Ulothrix,Spirogyra  etc.

-Dominating   phase   diploid
(2n).
-Haploid phase only in single cell or few celled gametophyte.
-Zygote forms embryo which
forms Sporophyte (main plant body).
eg.
Gymnosperms& Angiosperms

-Intermediate   i.e.haploid  &
diploid stages equal.
-Gametophyte & Sporophyte stages both may be free living.eg. Bryophytes & Pteridophyte.