Class 11 Biology Chapter 3 Plant Kingdom Notes

                             Plant Kingdom

1- Phylogeny-Evolutionary history of organism.

2- Zoospores-Motile spores with flagella.

3-Gametophyte-Haploid stage of plant, producing gametes.

4-Sporophyte-Diploid stage of plants producing spores.

5-Archegonium-Female reproductive structure.

6-Antheridium-Male reproductive structure.

7-Megasporangium-The structure which bears megaspores.

8-Sporophyll-Leaf bearing sporangia producing spores.

	-	Numerical taxonomy	-		based on several features compared collectively by computer.
	-	Cytotaxonomy	-		based on cytological features.
	-	Chemotaxonomy	-		based on chemical constituent.
Algae–
	-	Group of chlorophyllous, simple, thalloid plants.
	-	Largely aquatic, grow on soil, stone, wood etc or symbiotic.
	-	Unicellular to large filamentous.

Economically useful as-

a) Large photo synthesiser, release 02 .
b)Food for aquatic animals, humans.
c)Produce Algin (Brown algae), carrageen (red algae), agar (gelidium, gracilaria)

- Chlorella, Spirullina- in space travel as protein rich food.

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

Bryophytes ( Amphibians of plant Kingdom) – 

 Group of autotrophic plants with thallus having true roots, stem and leaves with multi cellular sex organs.
 Occurs on damp, humid and shaded soil.
 Root like rhizoids  present.
-Main plant body gametophyte bears Antheridia and Archegonia. Biflagellate antherozoids produced from Antheridium and reach through water to egg in Archegonium.
-Zygote forms sporophyte which produces haploid spores to give rise to new plants.

Types of Bryophytes

Liverworts

Mosses

1.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:
		-	Group of first terrestrial plants having vascular tissue viz. Xylem & Phloem.
		-	True stem, root & leaf.
		-	Found on damp, shady places.  Sporophyte makes main plant body.
		-	Sporophylls of Sporophyte bear sporangia (sori) onventral side producing haploid spores.
		-	spores give rise to Prothallus which is leafy & autotrophic.
		-	Prothallus bears sex organs – male – Antheridium and female- Archegonium.
		-	Fertilisation leads into zygote formation which produces diploid Sporophyte.
	Heterospory and Seed habit:
		-	Two types of spores Microspore and Megaspore are produced in some members viz. Selaginella, Salvinia.
		-	called Heterospory.
		-	Heterospory is considered as begining of seed habit in terrestrial plants.
			eg. Pteris, Dryopteris etc.
	GYMNOSPERMS
		-	Medium sized trees and shrubs.
		-	Main plant body Sporophyte
		-	In some members roots may have fungal association called Mycorrhiza.
	-bilus.
		-	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
		-	e.g. Cycas, Pinus ,Cedrusetc.
	ANGIOSPERMS
			Large no. of plants in varied habitats, small microscopic plants (Wolfia) to large trees
		-	Group of plants having covered seeds in fruits.
		-	Produce flowers having reproductive organs.
		-	Most evolved plants.

-Androecium  is  male  part  and  one  unit  is stamen.
-Gynoecium  is  female  part  and  one  unit  is carpel and has ovules.
-Ovule bears embryo sac.
-Embryo sac is seven celled and has Egg

01 –  haploid. Synergids
02 –   haploid. Antipodals
03 -  haploid. Secondary nucleus
04 –  diploid.

-Reproduction by vegetative and sexual methods.
-In sexual reproduction pollens shed off and reach to stigma of Gynoecium by pollination.
-Pollen germinates to form pollen tube with two male gametes and one tube nucleus.
-One  gamete  fuses  with  egg  (Syngamy)  and  other  with  secondary  nucleus  to  form  PEN  (primary endosperm nucleus). The whole process is called Double fertilization.
-Zygote forms embryo and PEN forms Endosperm in ovule which changes into seed inside fruit.
-Ovary wall changes into Pericarp (fruit wall).
-Alternation of generation occurs.

Plant life cycle and alternation of Generation –

-Alternate stages of haploid (n) and Diploid (2n) phase in life cycle of plants.

- Three Patterns -

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.