DAY TWO
Plant Kingdom
Learning & Revision for the Day
u Algae u Pteridophytes u Angiosperms
u Bryophytes u Gymnosperms u Alternation of Generations
l
Plant kingdom is composed of multicellular and photoautotrophic organisms. They
have cell wall made up of cellulose, exhibit indefinite growth and reserve food mainly
as starch.
l
Kingdom–Plantae has been further classified into following divisions namely–Algae,
Bryophytes, Pteridophytes, Gymnosperms and Angiosperms.
l
Eichler (1883) divided plant kingdom into two sub-kingdoms, mainly on the basis of
the presence or the absence of seeds.
1. Cryptogamae (Gr. Cryptos—hidden; gamous—marriage) are lower plants in which
sex organs are hidden and seeds and flowers are absent. It includes thallophytes
algae, bryophytes and pteridophytes.
2. Phanerogamae (Gr. Phaneros—visible/evident; gamous—marriage) are higher plants
in which sex organs are evident and seeds are present. It includes gymnosperms and
angiosperms.
Plant Kingdom
Sub-kingdom
Cryptogamae Phanerogamae
Divisions
Divisions
Gymnospermae Angiospermae
Thallophyta Bryophyta Pteridophyta
Classes
Classes
Cycadophyta Coniferophyta
Rhodophyceae Phaeophyceae Chlorophyceae Classes
Classes
Hepaticopsida Bryopsida
Dicotyledonae Monocotyledonae
Anthocerotopsida
Classes
Psilopsida Lycopsida Sphenopsida Pteropsida
, Algae
Salient features of algae are as follows
l
These are chlorophyll bearing, simple thalloid, autotrophic and largely aquatic (both freshwater and marine) organisms.
l
Algae occur in a variety of habitats like moist stones, soils and wood. Some of them also occur in association with fungi
(lichens) and animals (e.g. on sloth bear).
l
The size of algae ranges from the microscopic unicellular forms like Chlamydomonas to colonial forms like Volvox and to the
filamentous forms like Ulothrix and Spirogyra and herb forms like Chara.
l
Reproduction in algae occurs by vegetative, sexual and asexual methods.
l
Life cycle is of various types in algae, i.e. haplontic (Ectocarpus), diplontic (Fucus) and haplo-diplontic (Polysiphonia).
l
Algae are of paramount importance as these are primary producers which form the basis of the food cycles of all aquatic
animals.
Divisions of Algae and their Main Characteristics
Flagellar No.
Class Common
Major Pigment Stored Food Cell Wall and Position Habitat
(Example) Name
of Insertion
Chlorophyceae Green Chlorophyll-a and b Starch Cellulose 2-8, equal and Freshwater, brackish
(Ulothrix) algae apical water/salt water
Phaeophyceae Brown Chlorophyll-a, c Mannitol and Cellulose and algin 2, unequal and Freshwater (rare)
(Laminaria) algae and fucoxanthin laminarin lateral brackish water/salt
water
Rhodophyceae Red algae Chlorophyll-a, d Floridean Cellulose, pectin and Absent Freshwater (some),
(Batrachospermum) and phycoerythrin starch polysulphate esters brackish water/salt
water (most)
Some important algae are described below l
The zygospore after a resting period undergoes meiosis to
produce haploid meiozoospores, which under favourable
1. Ulothrix conditions germinate to produce new filament.
l
In Ulothrix, life cycle is of haplontic type.
It is a member of class–Chlorophyceae. It occurs in
freshwater bodies but Ulothrix flacca is marine and
U. implexa is lithophytic alga. 2. Batrachospermum (Frog Spawn Alga)
l
The thallus is unbranched filament consisting of basal It is a freshwater filamentous rhodophycean alga.
elongated and colourless cell called holdfast, the l
It’s filament gives a branched beaded appearance, due to
uppermost apical cell and row of rectangular cells (broader the presence of beads at the regions of nodes, where whorls
than longer). of short branches or glomerulus occur. Long branches
l
Each cell contains single nucleus, band-like or occur at some places.
collar-shaped chloroplast with one or more pyrenoids, l
Internodes are made up of single long cells. A loose cortex
a large central vacuole and cell wall of cellulose is also found around them.
impregnated by pectin is found. l
Cells of short laterals are small and elliptical.
l
Vegetative reproduction occurs by fragmentation and l
The alga can multiply vegetatively (by fragmentation and
asexual reproduction occurs by zoospores under favourable gemmae) and asexually (by monospores).
conditions. l
Male sex organs are called spermatangia, while female sex
l
The nucleus of each cell except holdfast divides mitotically organs are called carpogonia.
into 2-64 nuclei followed by accumulation of protoplasm l
Meiosis occurs immediately after fertilisation and a haploid
around these nuclei resulted in development of bi or carposporophyte or cystocarp is formed, which produces
quadriflagellate zoospores. carpospores.
l
During unfavourable conditions, the Ulothrix reproduces l
Carpospore forms a highly branched filamentous
asexually by hypnospores, akinetes and palmella stage. chantransia stage. It is juvenile stage, which can multiply
l
Sexual reproduction is isogamous type involving fusion of by monospores. The adult alga grows over the chantransia
two similar biflagellate gametes to produce zygospore. stage.
Plant Kingdom
Learning & Revision for the Day
u Algae u Pteridophytes u Angiosperms
u Bryophytes u Gymnosperms u Alternation of Generations
l
Plant kingdom is composed of multicellular and photoautotrophic organisms. They
have cell wall made up of cellulose, exhibit indefinite growth and reserve food mainly
as starch.
l
Kingdom–Plantae has been further classified into following divisions namely–Algae,
Bryophytes, Pteridophytes, Gymnosperms and Angiosperms.
l
Eichler (1883) divided plant kingdom into two sub-kingdoms, mainly on the basis of
the presence or the absence of seeds.
1. Cryptogamae (Gr. Cryptos—hidden; gamous—marriage) are lower plants in which
sex organs are hidden and seeds and flowers are absent. It includes thallophytes
algae, bryophytes and pteridophytes.
2. Phanerogamae (Gr. Phaneros—visible/evident; gamous—marriage) are higher plants
in which sex organs are evident and seeds are present. It includes gymnosperms and
angiosperms.
Plant Kingdom
Sub-kingdom
Cryptogamae Phanerogamae
Divisions
Divisions
Gymnospermae Angiospermae
Thallophyta Bryophyta Pteridophyta
Classes
Classes
Cycadophyta Coniferophyta
Rhodophyceae Phaeophyceae Chlorophyceae Classes
Classes
Hepaticopsida Bryopsida
Dicotyledonae Monocotyledonae
Anthocerotopsida
Classes
Psilopsida Lycopsida Sphenopsida Pteropsida
, Algae
Salient features of algae are as follows
l
These are chlorophyll bearing, simple thalloid, autotrophic and largely aquatic (both freshwater and marine) organisms.
l
Algae occur in a variety of habitats like moist stones, soils and wood. Some of them also occur in association with fungi
(lichens) and animals (e.g. on sloth bear).
l
The size of algae ranges from the microscopic unicellular forms like Chlamydomonas to colonial forms like Volvox and to the
filamentous forms like Ulothrix and Spirogyra and herb forms like Chara.
l
Reproduction in algae occurs by vegetative, sexual and asexual methods.
l
Life cycle is of various types in algae, i.e. haplontic (Ectocarpus), diplontic (Fucus) and haplo-diplontic (Polysiphonia).
l
Algae are of paramount importance as these are primary producers which form the basis of the food cycles of all aquatic
animals.
Divisions of Algae and their Main Characteristics
Flagellar No.
Class Common
Major Pigment Stored Food Cell Wall and Position Habitat
(Example) Name
of Insertion
Chlorophyceae Green Chlorophyll-a and b Starch Cellulose 2-8, equal and Freshwater, brackish
(Ulothrix) algae apical water/salt water
Phaeophyceae Brown Chlorophyll-a, c Mannitol and Cellulose and algin 2, unequal and Freshwater (rare)
(Laminaria) algae and fucoxanthin laminarin lateral brackish water/salt
water
Rhodophyceae Red algae Chlorophyll-a, d Floridean Cellulose, pectin and Absent Freshwater (some),
(Batrachospermum) and phycoerythrin starch polysulphate esters brackish water/salt
water (most)
Some important algae are described below l
The zygospore after a resting period undergoes meiosis to
produce haploid meiozoospores, which under favourable
1. Ulothrix conditions germinate to produce new filament.
l
In Ulothrix, life cycle is of haplontic type.
It is a member of class–Chlorophyceae. It occurs in
freshwater bodies but Ulothrix flacca is marine and
U. implexa is lithophytic alga. 2. Batrachospermum (Frog Spawn Alga)
l
The thallus is unbranched filament consisting of basal It is a freshwater filamentous rhodophycean alga.
elongated and colourless cell called holdfast, the l
It’s filament gives a branched beaded appearance, due to
uppermost apical cell and row of rectangular cells (broader the presence of beads at the regions of nodes, where whorls
than longer). of short branches or glomerulus occur. Long branches
l
Each cell contains single nucleus, band-like or occur at some places.
collar-shaped chloroplast with one or more pyrenoids, l
Internodes are made up of single long cells. A loose cortex
a large central vacuole and cell wall of cellulose is also found around them.
impregnated by pectin is found. l
Cells of short laterals are small and elliptical.
l
Vegetative reproduction occurs by fragmentation and l
The alga can multiply vegetatively (by fragmentation and
asexual reproduction occurs by zoospores under favourable gemmae) and asexually (by monospores).
conditions. l
Male sex organs are called spermatangia, while female sex
l
The nucleus of each cell except holdfast divides mitotically organs are called carpogonia.
into 2-64 nuclei followed by accumulation of protoplasm l
Meiosis occurs immediately after fertilisation and a haploid
around these nuclei resulted in development of bi or carposporophyte or cystocarp is formed, which produces
quadriflagellate zoospores. carpospores.
l
During unfavourable conditions, the Ulothrix reproduces l
Carpospore forms a highly branched filamentous
asexually by hypnospores, akinetes and palmella stage. chantransia stage. It is juvenile stage, which can multiply
l
Sexual reproduction is isogamous type involving fusion of by monospores. The adult alga grows over the chantransia
two similar biflagellate gametes to produce zygospore. stage.
