1. Batrachospermum is a freshwater red alga found in slow moving waters like lakes and streams in tropical and temperate regions. 2. The thallus appears as branching chains of beads and can reach 20 cm in length. It is differentiated into a main axis and two types of branches. 3. Reproduction occurs sexually through the formation of carpogonia and carposporophytes, and asexually through monosporangia and monospores which germinate to form the juvenile Chantrantia stage. 4. The life cycle is haplobiontic with an alternation between a diploid carposporophyte and haploid gametophyte generations

1. BATRACHOSPERMUM
Red Alga
Nisar Ahmad lone
Assistant Professor Botany
GDC Women Bla
RHODOPHYCEAE

3. CLASSIFICATION
Class Rhodophyceae
Sub-Class: Florideae
Order: Nemalionales
Family: Batrachospermaceae
Genus Batrachospermum

4. OCCURANCE
 Fresh water red alga
found in slow moving
waters of lakes, ponds,
streams in tropical and
temperate regions
 Some species attached
to stones in rivers
 Most species annual but
B.vagum perennial
 5 species in india
e.g, B .monaliformae,
B.vagum

5. OCCURANCE
The plants are blue-green, olive-green, violet and reddish
in colour.
The colour varies as a result of the differences in light
intensity. The species which grow in deep water are
reddish or violet in colour whereas the species growing in
shallow water are olive-green in colour.
The alga is also known as the ‘frog spawn’.
The plants are mucilaginous, moniliform or beaded in
appearance to the naked eye.
The plants may reach a length of twenty centimetres and
may easily be collected from the slow running streams
around Dehradun especially in winter season

6. THALLUS STRUCTURE
 The mature thallus is
branched, soft and gelatinous
 It Appears as the branching
chain of beads
 15 – 20 cms long and Blue
green, violet or red in color
depending on the intensity of
available light
 The thallus growing in deep
and shady ponds appear
violet or dark red

7. THALLUS STRUCTURE
 In shallow and illuminated
ponds the thallus appears
dark green in colour
 The Thallus differentiated into
a prostrate and an erect
system
 The prostrate branches
anchor the thallus to the
substratum whereas the
branches of erect system float
freely on water

8. THALLUS STRUCTURE
 The plant body consists
of central main axis
which is uniserriate
made up of elongated
cylindrical cells
 It is differentiated into
nodes and internodes
 Main axis corticated in
adult plants

10. THALLUS STRUCTURE
2 types of
branches arise
from nodes
• Branches of limited
growth (BLG)
• Branches of
unlimited growth
(BULG)

13. BRANCHES OF LIMITED GROWTH (BLG)
Produced in whorls from upper
ends of cells of axial filament just
below the septum
Made up of monaliform cells
Branches are of equal length and
each branches again to produce
cluster of branches at a node
called GLUMERULE
Gives Beaded appearance to the
thallus

15. BRANCHES OF UNLIMITED GROWTH
They arise from the nodal cells of
the main axis or te basal cells of
the branches of the limited growth
They are differentiated into nodes
and internodes
From their nodes branches of
limited growth arise

17. Branching in
Batrachospermum
• 2 main kinds of lateral
branches
• Branches of unlimited
growth
• Branches of limited
growth
Whorls of lateral
branches of limited
growth are called
Glomerule

18. CORTICATION
Nodal cells and the basal
cells of the BLG give rise
to some elongated
filamentous cells called
Cortical Threads
These grow down wards
to the next node forming
envelope around the
internode

20. CELL STRUCTURE
Cells uninucleate with several discoid
chromatophores along the periphery with single
pyrenoid
Main pigments : Chl a, Chl d, r- phycoerythrin and
r- phycocyanin
But due to the excess of red pigment green color
of chlorophyll is masked
Reserve food material – Floridean Starch
Pit connections between the cells of the axial
filament

21. GROWTH
 The main axis as well as the branches of unlimited
growth grow by means of a dome shaped,
hemispherical apical cell
 Repeated transverse divisions- uniseriate row of cell
 From the upper ends of each cell 4-6 protuberances are
given out which separate by means of septa to give rise
to Pericentral Cells
 Pericentral Cells function as the basal cells of BLG
 Branches of unlimited growth also develop from the
basal cells
 Basal cell also gives rise to corticating threads
 In older parts the basal cells separate and give rise to
node and the cells of the central axis elongate and form
internode

22. LIFE CYCLE
Reproduction
Asexual and Sexual

23. SEXUAL REPRODUCTION

24. SEXUAL REPRODUCTION

25. SEXUAL REPRODUCTION
Carpogonium

26. SEXUAL REPRODUCTION

27. FERTILIZATION

28. FERTILIZATION AND POST FERTILIZATION
CHANGES

29.  After fertilization Trichogyne shrivels
 Zygote undergoes meiosis- 4 haploid nuclei
 Nuclei divide repeatedly
 Protuberances formed on carpogonial wall
 Nuclei migrate into them
 Gonimoblast initials
 Divide repeatedly to form Gonimoblat filaments
 Terminal cell of gonimoblast filament forms
Carposporangium
FERTILIZATION AND POST FERTILIZATION
CHANGES

30. Single carpospore in each carposporangium
Carpospores- single, naked and non-motile
The lower sterile cells of the gonimoblast filaments give rise to many
sterile filaments which form an envelope around the carposporangia and
gonimoblast filaments
This composite structure is called Cystocarp of Carposporophyte
Carposporophyte i,e gonimoblast filaments and carposporangia and
sterile filaments grow as a parasite on the female plant
Carpospores liberated from carposporangia
FERTILIZATION AND POST FERTILIZATION
CHANGES

31. CARPOSORANGIUM

32. GERMINATION OF CARPOSPORE
Carpospores after being released
from the carposporangia get attached
t some substratum
Germinate by protonema formation
which is heterotrichous system
This stage is called juvenile stage or
Chantrantia stage as it was earlier
considered to be separate genus

33. GERMINATION OF CARPOSORE, MONOSPORANGIA AND
MONOSPORES, AND CHANTRANTIA STAGE

34. ASEXUAL REPRODUCTION

35. CHANTRANTIA STAGE
The erect branches of this heterotrichous juvenile
stage gives rise to adult Batrachospermum

36. LIFE CYCLE
Haplobiontic
Life cycle