TITLE :- RHODOPHYTA

NAME OF STUDENT :- PRIYANKA KHARE

COLLEGE NAME :- K.J.SOMAIYA COLLEGE OF SCI. & COM.

CLASS :- M. Sc. Part 1

FOR THE PAPER :- 1

FOR THE YEAR :- 2013-2014

RHODOPHYTA

Commonly called as Red algae

Majority of the red algae are marine.

Pigments :- r- phycocyanin , r- phycoerythrin , Chlorophylls , Carotenes & Xanthophylls

Reserved food material :- Floridean starch .

Total absence of flagellated ( vegetative as well as reproductive ) bodies.

Classification as followed By G. M. Smith in 1933

RHODOPHYTA

RHODOPHYCEAE

Division

Class

Sub-class

Order

Order :-

Bangiodeae Florideae

Bangioles

Nemalionales Gelidiales Cryptonemiales Gigartinales Rhodymeniales Ceramiales

Sub Class :- BangioideaeOrder :- Bangiales

E.g. :- Porphyra sps.

Porphyra perforata

Thallus is a smooth to greatly convoluted blade that is attached to the substratum by a disciform or cushion like holdfast.

Asexual reproduction by monospores.

Sexual reproduction by directly division of vegetative cells.

Cells contain one or two chromatophores.

It have a large centrally located pyrenoid .

Growing highly intertidal zone that’s why deep olive brown in colour.

Sub Class :- FlorideaeThe forms are always multicellular.

Plant body is filamentous . Filaments may aggregate to form a psedoparenchymatous or flat thallus.

Presence of pit connections in between the adjacent cells.

Auxiliary bud formation take place.

Sexual reproduction is very complex.

Male :- Spermatangium Female :- Carpogonium

Plants are mostly marine.

Order 1 :- Nemalionales

Batrachospermum

E.g. :- Batrachospermum

The body is bluish or violet green , multicellular , branched , soft , smooth.

The main axis is differentiated into nodes & internodes . From its node develop two types of branches i.e. branches of unlimited growth & branches of limited growth.

Sexually reproduction oogamous type.

Asexual reproduction by monospores.

Order 2 :- Gelidiales

Gelidium spp.

E.g. :- Gelidium

It is famous for providing the best source of agar – agar in the world.

Thalli have a single apical cell at each branch apex.

Carpogonial filament is unicellular & this single cell constitutes the carpogonium .

Tetrasporangia are usually crucinate.

Order 3 :- Cryptonemiales E.g. :- Dudresnaya crassa

An auxillary cell borne in special filament of the gametophyte.

The thallus is monoaxial & with derivatives from the single apical cell.

Each cutting off four lateral cells that are initials of branched lateral filaments whose cells contain chromatophores.

The gametophytes are heterothallic. Spermatangia & Carpogonial filaments are borne in nemathecia ( sori ) i.e. conceptacles.

Dudresnaya crassa

Order 4 :- Gigartinales

E.g. :- Gigartina

The thallus has more or less disciform holdfast bearing one or more erect shoots.

The gametophytes are heterothallic.

A procarp consist of supporting cell bearing a three celled Carpogonial filament.

The carposporophyte thus formed is freely branched and with many short lateral branchlets in which each cell develops into carposporangium.

Gigartina

Order 5 :- Rhodymeniales E.g. :- Gastroclonium coulteri

Plant show multiaxial construction.

Thallus is generally cylindrical, flattened or hollow & contains apical or marginal meristem.

Plants are diplobiotic with a definite procarp.

An auxillary cell is a special cell of the procarp & differentiated before fertilization.

Tetraspores are either tetrahedral or curciate. Gastroclonium coulteri

Order 6 :- Ceramiales

Polysiphonia

E.g. :- Polysiphonia

Thallus is uniaxial. The plant body is filamentous , psedoparenchymatous , reticulate & polysiphonous.

The carpogonial branch is 4-celled .

An auxillary cell is produced after fertilization . Carpospores develop to form teterasporophytes .

Haploid teraspores from gametophytes.

Two types of branches , normal & trichoblasts.

The cystocarp has a covering called as pericarp.

Reference Book :-

Algae by O. P. Sharma.

Cryptogamic Botany by G. M. Smith.