Question

In Spirogyra, asexual reproduction, takes place by
A. Fragmentation
B. Spore formation
C. Budding
D. Binary fission

Answer 1

Hint: Spirogyra is a green alga. It forms long filamentous colonies. Green algae have the ability to perform photosynthesis and these are autotrophic algae. According to Linnaeus, the algae are placed in Kingdom Plantae Different pigments are found in different algae which are responsible for their identification.

Complete answer:
All of these are different types of asexual reproduction employed by different organisms. The characteristics of some reproduction methods are described below :
> Fragmentation – It is a form of asexual reproduction in which the organisms are split into multiple small fragments. Each of these fragments will then develop into mature organisms. The splitting can happen unintentionally as well. Examples are Cyanobacteria, Spirogyra, Animals such as sponges, Annelid worms, etc.
> Spore formation – Spores are diploid (2n) cells that are specialized for reproduction. Spores are usually stored in specialized sacs called sporangia. These are held together by long thread-like structures called hyphae. Eventually, sporangia burst and disperse spores. Apart from asexual reproduction, spores help the organism to survive harsh conditions and develop in favorable ones. Examples are Ascomycetes, red algae, ferns, etc.
> Budding – This is a form of fission in which the daughter cell is smaller than the parent cell. The formation of buds occurs because of the cell division at a particular site. The outgrowth then gets separated and develops into a mature organism. Common examples are Baker’s yeast, Hydra, etc. There are instances of internal budding too, in which two daughter cells are formed internally, which will consume the mother cell and develop. Toxoplasma is an example of this.
> Binary fission – As the name suggests, it is the separation of an organism into 2, usually equal, parts. The organism duplicates its genetic material and divides it equally (1 copy each) in two daughter cells. It is the most common type of asexual reproduction in bacteria. Examples are, E. coli, Bacillus sp., amoeba, paramecium, etc.

In Spirogyra, asexual reproduction takes place by Fragmentation.

Note: The fragmentation usually occurs in multicellular organisms, and Spirogyra is a unicellular green alga. But remember that Spirogyra forms colonies with other members of the population and achieves its long filamentous multicellular like body. So even though they are unicellular, they reproduce by fragmentation. The sexual reproduction of Spirogyra is by the process of conjugation.