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Batrachospermum.pptx

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

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BATRACHOSPERMUM Red Alga Nisar Ahmad lone Assistant Professor Botany GDC Women Bla RHODOPHYCEAE
CLASSIFICATION Class Rhodophyceae Sub-Class: Florideae Order: Nemalionales Family: Batrachospermaceae Genus Batrachospermum
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
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
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
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
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
THALLUS STRUCTURE 2 types of branches arise from nodes • Branches of limited growth (BLG) • Branches of unlimited growth (BULG)
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
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
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
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
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
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
LIFE CYCLE Reproduction Asexual and Sexual
SEXUAL REPRODUCTION
SEXUAL REPRODUCTION
SEXUAL REPRODUCTION Carpogonium
SEXUAL REPRODUCTION
FERTILIZATION
FERTILIZATION AND POST FERTILIZATION CHANGES
 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
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
CARPOSORANGIUM
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
GERMINATION OF CARPOSORE, MONOSPORANGIA AND MONOSPORES, AND CHANTRANTIA STAGE
ASEXUAL REPRODUCTION
CHANTRANTIA STAGE The erect branches of this heterotrichous juvenile stage gives rise to adult Batrachospermum
LIFE CYCLE Haplobiontic Life cycle
Batrachospermum.pptx