Notes Plant Kingdom Class 11 Biology

Notes Class 11

Please refer to the Plant Kingdom Notes Class 11 Biology given below. These revision notes have been designed as per the latest NCERT, CBSE, and KVS books issued for the current academic year. Students will be able to understand the entire chapter in your class 11th Biology book. We have provided chapter-wise Notes for Class 11 Biology as per the latest examination pattern.

Revision Notes Chapter 3 Plant Kingdom Class 11 Biology

Students of Class 11 Biology will be able to revise the entire chapter and also learn all important concepts based on the topic-wise notes given below. Our best teachers for Grade 11 have prepared these to help you get better marks in upcoming examinations. These revision notes cover all important topics given in this chapter.

1. Kingdom plantae of Whittaker’s classification has

  • Algae,
  • Bryophyta,
  • Pteridophyta,
  • Gymnosperm &
  • Angiosperm.

2. Plants are

  • autotrophic (chlorophyll bearing),
  • eukaryotic,
  • Having cellulosic cell wall,
  • Tissue/organ level body organization.

3. ALGAE:

  • chlorophyll-bearing, autotrophic
  • Simple, Thalloid Body
  • Largely aquatic organisms.
  • Thallus means plant body is not differentiated into root, stem and leaf.
  • Lichen is symbiotic association of algae with fungi.
  • Algae also show symbiotic relationship with sloth bear.
  • Algae provide camouflage & mineral nutrition to bear whereas sloth bear give shelter and water.
  • Chlamydomos is microscopic unicellular. (now in Protista)
  • Colonial form-volvox (green algae)
  • Filamentous form-ulothrix and spirogyra (green algae).
  • Kelp (brown algae) form massive plant body.
  • Algae usually reproduce vegetative by fragmentation.
  • Asexual reproduction by formation of different types of spores (mainly through zoospore i.e. having flagella).
  • Sexual reproduction by formation of gametes
  • isogamy, anisogamy or oogamy.
  • Chlamydomonas (motile gametes), spirogyra (non-motile gametes) both show isogamy.
  • Some species of chlamydomonas also show Anisogamy
  • Volvox and Fucus show oogamy
  • Depending on the type of pigment possessed and the type of stored food, algae are classified into three main classes,
  • Chlorophyceae,
  • Phaeophyceae and
  • Rhodophyceae.
  • Lamanaria, sargassum and porphyra (brown algae) are used as food.
  • 70 species of marine algae are used as food.
  • About 50% of the world’s photosynthesis is done by algae
  • Increase the level of dissolved O2 in their immediate environment.
  • Important primary producers
  • § form the basis of the food chain of all aquatic animals.
  • o Agar(commercial products) obtained from Gelidium and Gracilaria
  • used to grow microbes
  • used in preparations of ice-creams and jellies.
  • Algin (from brown algae) and carrageen (from red algae) which are used commercially for their water holding capacity.
  • Chlorella a unicellular alga rich in proteins is used as food supplement even by space travellers.

4. CHOLOROPHYCEAE (Green algae):

  • Main pigment à chlorophyll a and b.
  • Stored food à starch.
  • Have one or more storage bodies à pyrenoids
  • located in the chloroplasts.
  • Pyrenoids contain protein besides starch.
  • Green algae usually have a rigid cell wall
  • made of an inner layer of cellulose and an outer layer of pectose
  • Number of flagella in motile cell à 2-8
  • they are equal in size and apical in position. Vegetative reproduction à by fragmentation.
  • Asexual reproduction à flagellated zoospores
  • produced in zoosporangia.
  • The sexual reproduction à isogamous, anisogamous or oogamous.
  • Example of green algae à
  • Chlamydomonas,
  • Volvox,
  • Ulothrix,
  • Spirogyra and
  • Chara
  • Volvox, spirogyra and some species of chlamydomonas show haplontic life (zygotic meiosis) cycle
  • main plant body is gametophyte
  • the only diploid cell in their life cycle is zygote.

5. PHAEOPHYCEAE (BROWN ALGAE):

  • Main pigments à chlorophyll a and c and fucoxanthin (brown colour).
  • Food is stored as complex carbohydrates à Laminarin or Mannitol.
  • The vegetative cells have a cellulosic wall usually covered on the outside by a gelatinous coating of algin.
  • The plant body is usually attached to the substratum by a holdfast, and has a stalk, the stipe and leaf like photosynthetic organ – the frond.
  • Vegetative reproduction takes place by fragmentation.
  • Asexual reproduction in most brown algae is by biflagellate zoospores.
  • Motile cells (zoospores and gametes) are pyriform and have two unequal laterally inserted flagella.
  • Sexual reproduction may be isogamous, anisogamous or oogamous.
  • The common examples are :
  • Ectocarpus,
  • Dictyota,
  • Laminaria,
  • Sargassum and
  • Fucus.
  • Kelp belongs to brown algae.
  • Fucus show DIPLONTIC LIFE CYCLE (sporic meiosis).
  • main plant body is diploid.

6. RHODOPHYCEAE (red algae):

  • Main pigments are chlorophyll a, d and r-phycoerythrin
  • r-phycoerythrin à reason of red colour
  • Majority of the red algae are marine
  • greater concentrations found in the warmer areas.
  • They occur in both well-lighted regions close to the surface of water and also at great depths in oceans where relatively little light penetrates.
  • The cel wall is made up of cellulose, pectin and polysulphate esters.
  • The food is stored as Floridian starch
  • very similar to amylopectin and glycogen in structure.
  • The red algae usually reproduce vegetatively by fragmentation.
  • Motile cells are completely absent in their life cycle.
  • Sexual reproduction is oogamous and accompanied by complex post fertilisation developments.
  • The common members are:
  • Polysiphonia,
  • Porphyra,
  • Gracilaria and
  • Gelidium.
  • Red algae are mainly marine.

7. BRAYOPHYTA: PLANT AMPHIBIANS

  • Plants which can live in soil but are dependent on water for sexual reproduction.
  • Therefore, their occurrence is limited to cool, damp and shady places.
  • Their plant body is more differentiated than that of algae.
  • It is thallus-like and prostrate or erect and attached to the substratum by rhizoids.
  • Vascular tissue is absent.
  • The main plant body of the bryophyte is GAMETOPHYTE (haploid).
  • It produces gametes.
  • The sex organs in bryophytes are multicellular and jacketed.
  • The male sex organ is called antheridium.
  • They produce biflagellate anthrozoids.
  • The female sex organ called archegonium
  • flask-shaped and produces a single egg.
  • Sexual reproduction is oogamous.
  • Fertilization requires water for anthrozoids movement.
  • After fertilization, zygote divide mitotically and produce multicellular embryo which then differentiated as sporophyte.
  • Sporophyte is the plant which produce haploid spores by meiosis (sporic meiosis).
  • Haploid spores germinate to form gametophyte.
  • Sporophyte is dependent upon gametophyte
  • for food and nourishment.
  • Bryophyte shows alternation of generation
  • between gametophyte and sporophyte.
  • Life-cycle is haplo-diplontic (sporic meiosis).
  • Bryophyta is the first evolved group where embryo formed
  • Species of Sphagnum, a moss, provide peat
  • § that have long been used as fuel,
  • § as packing material for trans-shipment of living material because of their capacity to hold water.
  • Since mosses form dense mats on the soil, prevent soil erosion.
  • They have great ECOLOGICAL IMPORTANCE as along with lichens they are pioneer of plant succession on bare rock/soil.
  • They decompose rocks making the substrate suitable for the growth of higher plants.
  • The bryophytes are mainly divided into liverworts and mosses.

8. LIVERWORTS:

  • Plant body is dorsiventrally thallod.
  • e.g. marchentia
  • Leafy members have tiny leaf-like appendages in two rows on the stem-like structures.
  • Asexual reproduction
  • takes place by fragmentation of thalli,
  • by the formation of specialised structures called gemmae.
  • Gemmae
  • green, multicellular, asexual buds
  • develop in small receptacles called gemma cups located on the thalli.
  • Become detached and germinate to form new individuals.
  • In marchentia,
  • anthridia (male sex organ) à
  • produce in receptacles called anthridiophore
  • archegonia (female sex organ) -à
  • produce in receptacles called archigoniophore
  • The sporophyte is differentiated into a foot, seta and capsule.
  • After meiosis, spores are produced within the capsule.
  • These spores germinate to form free-living gametophyte.

9. MOSSES:

  • Mosses gametophyte has two stage.
  • The first stage is the PRIMARY protonema stage, which develops directly from a spore. It is a creeping, green, branched and frequently filamentous stage.
  • The second stage is the leafy stage SECONDARY PROTONEMA which develops from the PRIMARY protonema as a lateral bud. They consist of upright, slender axes bearing spirally arranged leaf like structure.
  • They are attached to the soil through multicellular and branched rhizoids.
  • Secondary protonema bears sex organs.
  • Vegetative reproduction
  • by fragmentation
  • budding in the secondary protonema.
  • In sexual reproduction, the sex organs antheridia and archegonia are produced at the apex of the leafy shoots.
  • After fertilisation, the zygote develops into a sporophyte,
  • consisting of a foot, seta and capsule.
  • The sporophyte is more elaborate than that in liverworts.
  • The capsule contains spores.
  • Spores are formed after meiosis.
  • The mosses have an elaborate mechanism of spore dispersal.
  • Common examples of mosses are –
  • Funaria,
  • Polytrichum and
  • Sphagnum (peat moss).