rhodophyceae-22MBO025.pptx

ed algae or Rhodophyta – It is a distinctive type of species that are mostly found in the freshwater lakes and are the oldest type of eukaryotic algae.
They are red in colour due to the presence of a pigment called chlorophyll A, phycocyanin, and phycoerythrin. 
They are the member of the tribe Amansieae (Rhodomelaceae, Ceramiales, Rhodophyta), in which only Aneurianna and Lenormandia Sonder have foliar blades.
They are the distinctive type of species, mostly found in the deep freshwater bodies.

1. rhodophyceae SRIDHARSHINI.S 22MBO025 1 st M.Sc., BOTANY PSGR KRISHNAMMAL COLLEGE FOR WOMEN COIMBATORE-641004.

2. Red algae or rhodophyta Red algae or Rhodophyta – It is a distinctive type of species that are mostly found in the freshwater lakes and are the oldest type of eukaryotic algae. They are red in colour due to the presence of a pigment called chlorophyll A, phycocyanin , and phycoerythrin .  They are the member of the tribe Amansieae ( Rhodomelaceae , Ceramiales , Rhodophyta ), in which only Aneurianna and Lenormandia Sonder have foliar blades. They are the distinctive type of species, mostly found in the deep freshwater bodies .

3. history According to the original description of the genus (Phillips, 2006), Aneurianna differs from Lenormandia in having endogenous branching and elliptic surface pattern with various irregularly ordered ellipses on the blade (so-called “elliptical areolation”) and incurved or inflexed apices, in contrast to the absence of endogenous branching, rhombic surface pattern with regularly arranged rhombi (“rhombic areolation”).

4. General Characteristics of Red Algae Lack of flagella and centrioles Presence of photosynthetic pigments Found both in marine and freshwater They show biphasic or triphasic life cycle patterns. They are a multicellular, filament, blade structure. Stored food is in the form of starch and polymers of galactan sulphate A pit connection (hole in the septum) is formed between two algal cells. Have a diffuse growth pattern- Apical growth, Complex oogamy ( triphasic )

5. These group of red algae is generally found in tropical marine locations The mode of nutrition may either be saprophytic, parasitic or also epiphytic. Their cell walls consist of cellulose and many different types of carbohydrates. Grow on solid surfaces independently or sometimes found attached to other algae. Presence of pit in the cell walls, through which cytoplasmic connec­tions are maintained. The male sex organs are known as spermatangium and the female sex organs are called carpogonia or procarp . Mode of Reproduction: It takes place by all the three means: vegetative, asexual and sexual. Asexual mode of reproduction is by monospores and during the sexual mode of reproduction, they undergo alternation of generations.

6. reproduction Asexual reproduction By chantransia stage Sexual reproduction by Oogamy (by male and female sex organs)

7. Asexual reproduction The chantransia is haploid in structure. This forms the monosporangia . From the monosporangia the monospores are produced. Again the chantransia is fromed from the monospores and it develops the gametophyte.

8. Sexual reproduction It is reproduce sexually by oogamous type. It comprises the male and female reproductive sex organs called antheridia(male) and carpogonium(female). Its has two phases – fertilization and post fertilization.

9. CARPOGONIA The carpogonia is the terminal cell of the carpogonium. Carpogonium is flask shaped. And terminal. It has 2 parts called basal and distal- trichogyne Trichogyne has no nucleus. at maturity, from the procarp , the nucleus will travel to trichogyne and is known as egg. The trichogyne always receive the male reproductive cell. ANTHERIDIUM It is a single cell. It is produces the spermatia . Appear as a budded, grape like cells present at top. Spermatangia liberated the non-motile and spherical spermatium and they are naked.

10. fertilization The liberated spermatium (n) is reached to trichogonium by water currents. A large number of spermatium is failed to reach the egg(n) and they are degenerated. At last some of the spermatiua is reached to egg by trichogyne . The outer layer of the trichogyne is gelatinous and the spermatia is stick to it. The adjoining walls of the trichogyne is dissolved by spermatia . The male nucleus will join to the female nucleus to form the zygote. at last the diploid zygote(2n) will form.

11. Post fertilization In post fertilization, the zygote will undergo divide mitotically twice to produce 4 haploid nuclei. The haploid nuclei undergo continoues division and each nucleus posses protuberance. The protuberance will grow and separated by walls to form the carpogonium the outgrowth is seen which are known as gonimoblast . The gonimoblast continued the repeated division and forms a mass of branched and unbranched filaments, which is known as gonimoblast filaments. the terminal cell of the each gonimoblast filament becomes enlarged to function as carposporangium .

12. Carposporangium liberated the carpospores. The carpospores is single celled, naked, non-motile, haploid. The gonimoblast bears a structure, which are collectively called as carposporophyte . The carposporangium liberates t5he carpospores and are come to rest and screte a wall around it. After this process, it undergoes the transverse septation . The transverse septation projecting a erect filament branches are called as heterotrichous structure. The heterotrichous structure is commonly called as chantransia stage. This chantransia reproduce the monospores and developed into a protonema . The special type of alternation of generations are seen in red algae.

13. Post fertilization diagrammatic rep.,

14. Life cycle of bactrachospermum

15. Alternation of generation

16. Thank you