Plant Kingdom

Part-1

Algae

Prepared by
Rajalakshmi.K
GGHSS.Kallai
 Different types of classifications

➢ Artificial classification system –

It gave equal weightage to vegetative and

sexual characteristics .

Eg : Linnaeus classification
➢ Natural classification system -

It is based not only the external features,

but also internal features like ultrastructure,

anatomy (ആന്തരഘടന)

embryology (ഭ്രൂണശാസ്തഭ്രം)

and phytochemistry (സസയരസരഭ്ന്തം)

Eg : George Bentham and Joseph Dalton

Hooker‘s classification
➢ Phylogenetic classification system is based on evolutionary

relationships (പരിണാമ ബന്ധങ്ങൾ) between various

organisms .This assumes that organisms belonging to the

same taxa have a common ancestor.

➢ Numerical Taxonomy is now easily carried out using

computers and is based on all observable characteristics.

➢ Cytotaxonomy is based on cytological
information like
chromosome number,
structure, behaviour.
➢ Chemotaxonomy is based on the chemical
constituents (രാസഘടകങ്ങൾ)

of the plant
 Kingdom Plantae is divided into 5 divisions

Algae Bryophyte Pteridophyte

Gymnosperm Angiosperm
 Algae
➢ Algae are thalloid, autotrophic aquatic organisms

➢ They occur in different forms

.
Unicellular form Colonial form
Eg : Chlamydomonas Eg : Volvox
.

Filamentous forms Gaint Kelps

Eg : Spirogyra Eg : Fucus
The algae reproduce by different methods
➢ Vegetative
➢ Asexual
➢ Sexual methods.

Vegetative reproduction is by Fragmentation.

Each fragment develops into a thallus.
➢ Asexual reproduction takes place by different types of spores

➢ The most common type is by zoospores.

➢ They are flagellated, motile spores.

➢ They germinate and gives rise to new plants.

Zoospores of Chlamydomonas
Sexual reproduction takes place by the fusion of two gametes.
It is of three types

1) Isogamous -
Fusion of two gametes similar in size. Eg : Spirogyra
2) Anisogamous –
Fusion of two gametes dissimilar in size. Eg : Chlamydomonas
3) Oogamous -
Fusion between one large non-motile female gamete and
a smaller motile male gamete . Eg :Volvox, Fucus.
Algae are divided into three main classes based on

the presence of the pigments .

1) Chlorophyceae – Green algae

2) Phaeophyceae - Brown algae

3) Rhodophyceae – Red algae

 Algal Common Major Stored Cell wall Examples
class Name Pigments food

Chara
Chlorophyceae Green Chlorophyll Starch Cellulose Volvox
algae a & b & Chlorella
Pectin Spirogyra
Chlamydomonas
Brown Chlorophyll Mannitol Cellulose Fucus
Pheophyceae algae a & c & & Dictyota
Laminarin Algin Laminaria
Fucoxanthin Sargassum

Rhodophyceae Red Chlorophyll Floridean Cellulose Gelidium

algae a & d starch Gracilaria
Polysiphonia
Phycoerythrin

Thank you
 Green algae... Ulva

Spirogyra

Chara
 Brown algae ....
Dictyota

Sargassum

Ectocarpous
 Red algae ...

Gracilaria

Polysiphonia

Gelidium
➢ Most of the green algae members have one or more

storage bodies in the chloroplasts called as Pyrenoids.

Pyrenoids contain starch and proteins.

➢ Some Brown algae members are highly branched
giant forms and are called as Kelps.
➢ 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.
 Economic importance

➢
The Green algae, Chlorella is rich in proteins which is used as
food supplement even by space travellers

➢ Many species of marine algae like Porphyra, Laminaria and

Sargassum are used as food.
➢
Hydrocolloids - water holding substances,

like Algin, which is obtained from brown algae

is used as food additive

➢ Agar ( China grass / Veg gelatin) which is obtained from the

Red algae Gelidium and Gracilaria are used to grow microbes

and in the preparations of ice-creams and jellies.

➢
The water holding substance- Carrageen is also obtained from
Red algae which is used commercially.

Thank you
Plant Kingdom
Part – 2
Bryophytes

Prepared by
Rajalakshmi.K
GGHSS.Kallai
Bryophytes are also called amphibians of the plant kingdom

because these plants can live in soil but are

dependent on water for sexual reproduction.

➢ The plant body of bryophytes is thallus-like, prostrate or

erect, and attached to the substratum by rhizoids.

➢ They lack true roots, stem or leaves.

➢ They may possess root-like, leaf-like or stem-like structures.

Thallus

Rhizoids
 Bryophytes are divided into two

Liverworts & Mosses

❖ The main plant body of the bryophyte is haploid (n).
❖ It produces gametes, hence is called a Gametophyte.
❖ The male sex organ is called Antheridium which
produces male gametes - Antherozoids (n).
❖ The female sex organ is called Archegonium , which
produces female gamete- a single Egg (n).

. Archegonium
Antheridium
❖ During fertilisation an antherozoid fuses with the egg
to produce the Zygote(2n).
❖ The zygote develops into a multicellular body called a
Sporophyte, which undergoes Meiosis to produce
Haploid Spores(n)
❖ These spores germinate to produce new gametophyte (n)

Spores

Sporophyte
❖ Liverwort

The plant body of a liverwort is a thalloid structure.

Marchantia Riccia
❖ Asexual reproduction takes place by fragmentation of thallus

or by the formation of specialised structures called Gemmae.

❖ Gemmae are green, multicellular, asexual buds, which

develop in small cup shaped structures , Gemma cups.

❖ The gemmae detached from the parent body and germinate

to form new individuals.

❖ During sexual reproduction, male and female sex organs

are produced either on the same or on different thalli.

❖ Male sex organs are produced on Antheridiophores.

❖ Female sex organs are produced on Archegoniophores.

Antheridiophore Archegoniophore
❖ After fertilization the zygote delevops into a sporophyte.

❖ Sporophyte is differentiated into a foot, seta and capsule.

❖ After meiosis, spores are produced within the capsule.

❖ These spores germinate to form free-living gametophytes.

Marchantia sporophyte

foot
seta
capsule
spores
❖ Moss

❖The predominant stage of the life cycle of a moss

is the gametophyte which consists of two stages.

❖ The first stage is the Protonema stage,

which develops from a spore

❖ The second stage is the Leafy stage, which consist of

upright, slender axes bearing spirally arranged leaves.

❖ They are attached to the soil by rhizoids.

Protonema stage Leafy stage
❖ 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 capsule contains spores which are formed after meiosis.

❖ Eg : Funaria, Polytrichum and Sphagnum

Funaria Sphagnum
 Economic importance

❖ Species of Sphagnum moss provide peat that have been

used as fuel .

❖ It is used as packing material because of their capacity

to hold water
 Ecological importance

❖ Mosses along with lichens are the first organisms to colonise rocks.

❖ They help in soil formation.

❖ Since mosses form dense mats on the soil, they reduce the impact

of falling rain and prevent soil erosion.

Plant Kingdom
Part - 3
Pteridophytes

Prepared by
Rajalakshmi.K
GGHSS Kallai
➢ Pteridophytes are the first terrestrial plants which possess

vascular tissues – xylem and phloem.

➢ In Pteridophytes plant body is a diploid Sporophyte (2n)

which is differentiated into true root, stem and leaves

Sporophyte
 The leaves in Pteridophytes are called as Sporophylls

which contain Sporangia.

Meiosis takes place inside the Sporangia to form

Haploid Spores (n).

Sporophyte Sporophyll Sporangia Spores

The spores germinate to give rise to inconspicuous, small,

multicellular, free-living, mostly photosynthetic thalloid

gametophytes called Prothallus.

Prothallus.
➢ The Prothallus bear male sex organs called antheridia and
female sex organs archegonia.
➢ The male gametes Antherozoids are released from the
antheridia, to the mouth of archegonium which contains
the female gamete Egg .
➢ Fusion of male gamete with the egg result in the
formation of zygote which later develops into a new
sporophytic fern plant
 Spore germination
Spore (n)

Meiosis

Sporangia (2n) Prothallus Antheridia

with sperm
Gametophyte (n)
(n)
Archegonia
with egg (n)

Sporophylls. Fertilisation

Zygote
(2n)

Fern plant - Sporophyte

(2n)
➢ In majority of the pteridophytes all the spores are of similar kinds;

such plants are called Homosporous.

➢ But genera like Selaginella and Salvinia produce two kinds of spores,

small Microspores & large Macrospores and such plants are called

Heterosporous.

Homosporous Heterosporous
➢ The microspore germinate and gives rise to

male gametophyte which produces male gametes.

➢ The megaspore germinates and gives rise to

female gametophyte which produces female gamete.

➢ After fertilisation the zygote develops into an

young embryo within the female gametophyte,

which are retained on the parent sporophyte.

➢ This event is a precursor to the seed habit, which

considered an important step in evolution.

Pteridophytes include Ferns & Horsetails

They are further classified into four classes

1) Psilopsida (Psilotum)

2) Lycopsida (Selaginella, Lycopodium)

3) Sphenopsida (Equisetum)

4) Pteropsida (Dryopteris, Pteris, Adiantum)

Psilotum Equisetum

Adiantum
Selaginella Salvinia

Pteris
Plant Kingdom
Part-4

Gymnosperms

Prepared by
Rajalakshmi.k
GGHSS Kallai
❖ Gymnosperms are naked seed plants.

❖ They are usually medium-sized trees or

tall trees and shrubs.

❖ The giant redwood tree Sequoia is one

of the tallest tree species,
❖ Pinus roots have fungal association in the

form of Mycorrhiza

❖ Cycas have small specialised roots called

Coralloid roots which associated with

N2- fixing cyanobacteria.

N2- fixing
cyanobacteria
❖ The gymnosperms are heterosporous.

❖ They produce spores on specialised structures called Cones.

❖ Microspores develop within the Microsporangia in Male cone.

❖ Megaspores develop within the Megasporangia in Female cone.

Male cone Female cone
❖ Microspore develops into male gametophyte and

is called as Pollen grain.

❖ Megaspore develops into Female gametophyte

called Archegonium.

❖ Male gametophyte produces Male gamete.

❖ Female gametophyte produces Female gamete.

❖. The Pollen grain germinates and forms a pollen tube

which carry the male gametes towards archegonia

within the ovules.

❖ Archegonia contains the female gamete.

❖ The Male & Female gamete fuse together during

fertilisation to form a Zygote.

❖ After fertilisation,Zygote develops into an Embryo

and Ovules develop into Seed which are not covered .

❖ Seeds germinate to form a new Sporophytic plant.

 Plant –Sporophyte (2n)

Male Cone Female cone

Microsporophyll Megasporophyll

Microsporangium Megasporangium

Microspore (n) Megaspore (n)

Male gametophyte Female gametophyte

Pollen grain Archegonia inside ovule

Male gamete (n) Female gamete (n)

Zygote (2n)

New plant – Sporophyte (2n)

Pinus Cycas
Cycas Male cone Cycas Female cone

Thank you
Plant Kingdom
Part-4

Angiosperms

Prepared by
Rajalakshmi.K
GGHSS Kallai
✓ Angiosperms are flowering plants.

✓ They have seeds enclosed in fruits.

➢ Angiosperms are divided into two classes

➢ Dicotyledons and Monocotyledons

➢ Dicotyledons have two cotyledons in their seeds

➢ Monocolyledons have only one cotyledon in their seeds

Dicot seed Monocot seed

Eg:Bean seed Eg :Wheat seed
✓ In Angiosperms, flower is the reproductive organ.
➢ The male sex organ in a flower is the Stamen.

➢ Each Stamen has an Anther at its tip.

➢ Meiosis takes place inside the anthers to form

Pollen grains.

➢ Pollen grains represents the Male gametophyte.

➢ Each pollen grain produces two Male gametes.

➢ The female sex organ in a flower is the

Pistil or Carpel.

➢ Pistil consists of an ovary enclosing one to

many Ovules.

➢ Inside the ovule Megaspore mother cell undergoes

Meiosis to form Megaspore which later forms

an Embryosac.
 Embryosac
Antipodals

Each embryo-sac has

➢ one Egg cell-

Central cell
the female gamete
Polar nuclei
➢ two Synergids
Egg cell
➢ three Antipodal cells

➢ two Polar nuclei

Synergids
➢ Pollen grains from the anthers, are carried by

wind or various other agencies to the

female reproductive part – stigma of a pistil.

➢ This is termed as Pollination.

After pollination ,the pollen germinates and the pollen tube

carries the two male gametes towards the female gamete for

the process of Fertilisation.

The pollen tube releases the two male gametes into the

Embryosac.

Pollen tube

Embryo sac

Male gametes
 Two fusions takes place within the embryosac

➢ Syngamy – fusion of one male gamete with the

female gamete to form a diploid zygote
Male gamete (n) + Female gamete (n) = Zygote (2n)

➢ Triple fusion - fusion of two haploid Polar nuclei

with the other male gamete to form
triploid Primary Endosperm Nucleus
PN (n) + PN (n) + Male gamete (n) = PEN (3n)
➢ Since two types of fusions, Syngamy & Triplefusion

take place in an Embryo sac, the phenomenon is

termed Double fertilisation.

➢ The Zygote develops into an Embryo.

➢ The PEN develops into Endosperm

which provides nourishment to the Endosperm

developing embryo.
Embryo
 After fertilisation ,

➢ Ovules develop into seeds and

➢ Ovary develops into fruit.

Plant Kingdom
Part – 5

Plant Life cycles

Prepared by
Rajalakshmi.K
GGHSS Kallai
➢ In the life cycle of any sexually reproducing plants

there are two phases;

➢ Gametophytic phase & Sporophytic phase

which alternates each other.

➢This phenomenon is called as Alternation of generation.

➢ Depending upon the duration of these

phases it is of 3 types

1) Haplontic life cycle

2) Diplontic life cycle

3) Haplo – Diplontic life cycle

1) Haplontic life cycle

➢ In this type of life cycle

haploid Gametophyte is

the dominant phase

➢ Gamates fuses to form a diplod

zygote which develops into a

Sporophyte
➢ Sporophytic generation is

represented only by the

one-celled zygote.

➢ Meiosis take place in the

zygote to form haploid spores.

Eg : Algae Volvox,

➢ The haploid spores divide mitotically Spirogyra

and some species of
and form the gametophyte.
Chlamydomonas
2) Diplontic life cycle

➢ In this type, diploid Sporophyte

is the dominant, photosynthetic,

independent phase of the plant.

➢ Eg : An algae, Fucus
Gymnosperms &
Angiosperms
➢ Meiosis takes place to form a

single to few-celled haploid

gametophyte which represents

the Gametophytic stage.

➢ Gamates fuses to form a diplod

zygote which develops into a

Sporophyte
 3) Haplo- Diplontic life cycle

➢ All Bryophytes and pteridophytes

exhibit this pattern

➢ Bryophytes have a dominant,

independent, haploid gametophyte

which alternates with a shortlived

multicelluler sporophyte dependent

on the gametophyte.
➢ Pteridophytes have a dominant,

independent, photosynthetic,

vascular plant body which is a

diploid sporophyte.

➢ It alternates with multicellular,

independent but short-lived

haploid gametophyte. Thank you

➢ Eg: Algae like Ectocarpus,

Polysiphonia, Kelps
Bryophytes & Pteridophytes