Question

Non-motile, greatly thickened, asexual spore in chlamydomonas is
A. Carpospores
B. Akinetes
C. Aplanospores
D. Hypnospores

Answer 1

Hint: Spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. It is a reproductive cell capable of developing into a new organism. Spores are produced by Algae, Fungi, Bacteria and Plants.

Complete answer:
Chlamydomonas is a genus of green algae (Chlorophyceae). The green colour is due to the presence of chlorophyll a and b. Both sexual and asexual reproduction takes place in chlamydomonas.
Asexual reproduction by zoospores, aplanospores, hypnospores or by palmella stage and Sexual reproduction by isogamous, anisogamous and oogamous reproduction.
Carpospores: These are the spores produced by the members of Rhodophyceae (Red algae). It is a diploid, non- motile spore. After fertilization, the carpogonium of algae divides into carpospores and after that, the walls of carpal sporangium burst and the spores scattered in the environment.
Akinetes: It is a thick walled dormant cell formed from the enlargement of a vegetative cell of filamentous, heterocyst forming cyanobacteria. These are resistant to harsh conditions such as cold, heat and desiccation. It is a resting cell of cyanobacteria.
Aplanospores: In this, the protoplast separates from the parent cell wall, rounds up and develops into thin walled, non-motile spores, which may either germinate directly or divide to produce zoospores.
Hypnospores: In this, the protoplast separates from the parent cell wall, rounds up and develops into thick walled, non-motile spores. They usually develop red colour due to haemato chrome pigment.

So the correct answer is option D.

Note: The genus Chlamydomonas has two anterior flagella each as long as the other. Chlamydomonas genus consists of about 325 species.