Question

Which one is used as a biofertilizer?
(a)Nostoc
(b)Funaria
(c)Volvox
(d)Rhizopus

Answer 1

Hint: Biofertilizers are substances that contain living or latent cells that increase the nutrients of host plants when applied to their surface or soil by colonizing the rhizosphere. Some Biofertilizers are nitrogen fixers that fix that atmospheric nitrogen so that the plant can use it.

Complete answer:
From the given options, Nostoc is used as a biofertilizer for its ability of nitrogen-fixing. Nostoc is blue-green algae that fixes atmospheric nitrogen into ammonia and the plants can use this ammonia for their living processes. Thus nostoc acts as a free-living or symbiotic nitrogen-fixing bacteria for the plants and therefore, is used as a biofertilizer.

Additional information:
Nostocs are Cyanobacteria or blue-green algae that live in colonies in various environments like soil, moist rocks, freshwater, and marine habitats and sometimes as free-living as well as symbiotes with the tissues of plants like Gunnera, Hornworts, etc. In symbiotic relation, they provide nitrogen to the host plant with the help of heterocysts which are terminally differentiated specialized cells for nitrogen-fixing. They live as free-living organisms as they can carry out Photosynthesis with the help of their photosynthetic pigments.

So, the correct answer is "nostoc".

Note: Funaria is a moss that grows in dense patches or cushions in moist shady places mainly during the rainy season. They are radially symmetrical with an axis, phylloid, and oblique septa. These are mainly autotrophic. On the other hand, volvox is Chlorophyta green algae that live in colonies and obtain their nutrition by Photosynthesis. Rhizopus are saprophytic fungi on plants and parasites on animals and are found in a wide variety of organic substances. They generally grow as filamentous, branching hyphae and reproduce by asexual and sexual spores.