Morphology and Reproductive structures of Battrachospermum

For PG and UG students

1. BATRACHOSPERMUM

Red Alga

Nisar Ahmad lone
Assistant Professor Botany
GDC Women Bla

3. CLASSIFICATION

4. OCCURANCE

o Fresh water red alga
found in slow moving
waters of lakes, ponds,
streams in tropical and
temperate regions

o Some species attached
to stones in rivers

o Most species annual but
B.vagum perennial

o 5 species in india
e.g, B.monaliformae,
B.vagum

5. 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

o The mature thallus is
branched, soft and gelatinous

olt Appears as the branching
chain of beads

o 15 — 20 cms long and Blue
green, violet or red in color [|g
depending on the intensity of
available light

o The thallus growing in deep
and shady ponds appear
violet or dark red O

7. THALLUS STRUCTURE

o In shallow and illuminated
ponds the thallus appears
dark green in colour\

o The Thallus differentiated into
a prostrate and an erect
system

o The prostrate branches
anchor the thallus to the
substratum whereas the Vale
branches of erect system flo all
freely on water

8. THALLUS STRUCTURE

o The plant body consists
of central main axis
which is uniserriate
made up of elongated
cylindrical cells

oltis differentiated into
nodes and internodes

o 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)

12. ee

y WHORLS OF A
B LATERALS

Fig. 7.7. Batrachospermum, A, portion of plant: B, two whorls of laterals;
C, short laterals; D, basal cell with laterals.

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

16. BRANCH OF a)
UNLIMITED GROWTH

o

BRANCHES OF
LIMITED GROWTH

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

19. m

A

Fig. 7.7. Batrachospermum. A, portion of plant; B, two whorls of laterals;
* €, short laterals; D, basal cell with laterals.

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

o The main axis as well as the branches of unlimited
growth grow by means of a dome shaped,
hemispherical apical cell

o Repeated transverse divisions- uniseriate row of cell

o 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

o Pericentral Cells function as the basal cells of BLG

o Branches of unlimited growth also develop from the
basal cells

o Basal cell also gives rise to corticating threads

o 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

23. SEXUAL REPRODUCTION
Sexual reproduction (oogamous)

Male sex organs: spermatangia (antheridia)
Female sex organs: carpogonia

Carpogonia
Borne terminally on short carpogonial branches

Any basal cell of primary branch of limited growth starts
behaving as initial of carpogonial branch (procarp) which
divides to form carpogonial branches. The terminal cell of
this branch becomes modofied into flask shaped
carpogonium.

The upper neck shaped part is called trichogyne

The nucleus lies in swollen basal portion which divides into )
two. One remains in the carpogonium and functions as egg
nucleus, other nucleus degenerates

24. SEXUAL REPRODUCTION

Spermatangia

+ Borne in clusters on short spermatangial branches

+ Spermatangial branches arise in same way as
branches of limited growth

« Terminal cell of each branch behave as
spermatangium mother cell which bears mother cell

* spermatangium mother cell produce 1-2

SPERMATIUM

B: Development of antheridium
C: Single mature antheridial
branch showing spertangium

ANTHERIDIAL.
FILAMENTS

25. SEXUAL REPRODUCTION
Carpogonium

ypogynous cen

CARPOGONIAL
FILAMENT

A-B: Development of carpogonial branches
C: single carpogonial branch with young carpogonium

26. SEXUAL REPRODUCTION

27. FERTILIZATION

Fertilization

+ The male nucleus’ migrates into
trichogyne through opening in
spermatium.

* The male nucleus divides into two in
trichogyne, one moves downwards and
fuses with egg nucleus to form zygote.

28. FERTILIZATION AND POST FERTILIZATION
CHANGES

Fertilization
and post
fertilization
changes in
Batrachosp-
ermum

29. FERTILIZATION AND POST FERTILIZATION
CHANGES

o After fertilization Trichogyne shrivels

o Zygote undergoes meiosis- 4 haploid nuclei

o Nuclei divide repeatedly

o Protuberances formed on carpogonial wall

o Nuclei migrate into them

o Gonimoblast initials

o Divide repeatedly to form Gonimoblat filaments

o Terminal cell of gonimoblast filament forms
Carposporangium

30. FERTILIZATION AND POST FERTILIZATION
CHANGES

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

31. CARPOSORANGIUM

A: Female branch showing terminal carposporangia
B: Liberation of carposporangia |

ct aod Finals show! E 4

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 O

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

34. ASEXUAL REPRODUCTION

Asexual reproduction: In several species of Batrachospermum the short branches of the
filaments of Chantransia stage produce monospores. These monospores again produce
Chantransia stage, and again the apical cells of this stage produce new plants.

35. CHANTRANTIA STAGE

The erect branches of this heterotrichous juvenile
stage gives rise to adult Batrachospermum

36. Ww
=
O
>
©
Lu
=
—

37. THANKS