Batrachospermum

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

3. Classification

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

13. Branches of limited growth (BLG)

15. Branches of unlimited 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

20. Cell Structure

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 • PericentralCells 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

23. Sexual Reproduction

24. Sexual Reproduction

25. Sexual Reproduction Carpogonium

26. Sexual Reproduction

27. Fertilization

28. Fertilization and post fertilization changes

29. 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

30. Fertilization and post fertilization changes

31. Carposorangium

32. Germination of Carpospore

33. Germination of Carposore, Monosporangia and monospores, and Chantrantia stage

34. Asexual Reproduction

35. Chantrantia stage

36. Life Cycle Haplobiontic Life cycle

37. Thanks