Chlorophyceae PPT BY Dr.Pinky Diwedi

1. Chlorophyceae
M.Sc.Isem, unit-II
Dr. Pinky Dwivedi

2. • Cells are eukaryotic, green algae.
• Thallus is green,
• chl.a,chl.b,carotenoid pigments are present in
chloroplast.
• Chlorophyll is predominant over carotenoid
pigments.

3. • In chloroplast proteinaceous bodies- pyrenoid
surrounded by sheath of starch.
• Vacuoles in cytoplasm.
• Motile cells in primitive forms have eye spot or
stigma.
• Cell wall is made up of cellulose.
• Reserved food material is starch.
• Flagella 2-4 ,anterior in position, whiplash type.
• Reproduction : vegetative-cell division, fragmentation.
• Asexual reproduction- akinetes,zoospores,aplanospores.

4. Predominantly freshwater-90% about 10%-marine
Oedogoniales,Conjugales-freshwater.
Siphonales,Ulvale- marine
Cladophorales,Volvocales,Chaetophorales –freshwater
and marine.
Ulothrix, and Zygonema –sub-aerial.
Protococcus ,Trentepholia –epiphytic.
Spp.of cladophora , characium- epizoic.
Chlorella – endophytic.
Cephaleuros ,rhodochytrium –parasitic.
Chlorella- thermophilic.
Chlamydomonas yellowstonensis,Haematococcus
nivalis – snow.

5. Chlamydomonas ehrenbergii –saline.
Thallus structure:
Unicellular motile –Chlamydomonas,Sphaerella
Unicellular non-motile-Chlorella,Chlorococcum.
Colonial-motile coenobium-Pandorina,Volvox.
Non motile- Hydrodictyon.
Palmelloid- Tetraspora.
Dendroid- Ecballocystis.
Filamentous unbranched- Ulothrix,Oedogonium.
Filamentous branched- Cladophora.
Heterotrichous-Fritschiella,Stigeoclonium.

6. Siphonaceous- Protosiphon,Acetabularia.
Parenchymatous- Ulva.
• Shape of the chloroplast shows variation-
• Cup shaped-Chlamydomonas
• Girdle shaped –Ulothrix
• Reticulate-Oedogonium
• Parietal- Drapnaldiopsis
• Stellate-Zygnema
• Spiral- Spiroigyra

7. Flagella
motile cells- 2/4 flagella equal in length(isokont)
Inserted at anterior end.
In oedogoniales motile cells have ring of flagella.
Flagella are whiplash type (acronematic).
Base- blepharoplast or basal
Reproduction:
Vegetative
Asexual
Sexual

8. • Vegetative: parent cell wall is retained.
Cell division- unicellular forms –fisson.
Fragmentation – breaking up of filamentous thallus into
segments- fragments.
Asexual: by asexual spore, produced endogenously in specialised
structures –sporangia. Mitospores (formed
by mitosis) may be motile or non-motile.
Zoospores: bi-quadriflagellated- Ulothrix
multiflagellated- Oedogonium
aplanospores- in subaerial algae
in aquatic forms formed under unfavourable
conditions.
aplanosporeswith thick walls around it are called
hypnospores.

9. • Sexual reproduction: involves plasmogamy
followed by karyogamy of two specialised
reproductive cells called gametes.
Isogamy: Chlamydomonas, Zygnema
Anisogamy: Physiological- Spirogyra
(difference in motility)
Morphological- Entermorpha
Oogamous: In higher forms male-antheridium,
female- oogonium eg: Oedogonium.

10. • After fertilisation zygote is formed & it
undergoes resting phase (zygospore).
In Spirogyra, Zygnema – zygotic meiosis only
one meiospore is functional.
Ulothrix, Oedogonium all four meiospores are
functional.
Cladophora: zygote germinates and forms a
diploid filament or sporophyte – zoosporangia
in which meiospores are formed which
germinates and forms a haploid gametophyte,
shows distinct alternation of generation.