Match List-I with List-II
| List-I | List-II |
|---|---|
| Microbes | Features |
| (A) Glomus | (I) Atmospheric nitrogen |
| (B) Azospirillum | (II) Roots of leguminous plants |
| (C) Oscillatoria | (III) Free living in the soil |
| (D) Rhizobium | (IV) Mycorrhizae |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A) - (IV), (B) - (III), (C) - (I), (D) - (II)
(A) Glomus — this matches (IV) Mycorrhizae. Glomus is a fungus. Its filaments live with the roots of a plant as a mycorrhiza. The fungus takes up phosphorus from the soil for the plant, and the plant gives it food.
(B) Azospirillum — this matches (III) Free living in the soil. It is a free-living bacterium. It fixes nitrogen in the soil and so adds to the nitrogen content of the soil.
(C) Oscillatoria — this matches (I) Atmospheric nitrogen. It is a cyanobacterium, an autotrophic microbe that can fix atmospheric nitrogen.
(D) Rhizobium — this matches (II) Roots of leguminous plants. It lives in the root nodules of leguminous plants, such as pea and gram, and fixes nitrogen for the plant.
Note: Azospirillum and Rhizobium also fix atmospheric nitrogen, so (I) could fit them too. But Glomus fits only (IV), Rhizobium fits (II) and Azospirillum fits (III). This leaves (I) for Oscillatoria. Only Option (4) is consistent with this.
NCERT Extract:
Microbes as Biofertilisers – “… You have studied about the nodules on the roots of leguminous plants formed by the symbiotic association of Rhizobium. These bacteria fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient. Other bacteria can fix atmospheric nitrogen while free-living in the soil (examples Azospirillum and Azotobacter), thus enriching the nitrogen content of the soil.”
Microbes as Biofertilisers – “… Many members of the genus Glomus form mycorrhiza.”
Microbes as Biofertilisers – “… Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen, e.g. Anabaena, Nostoc, Oscillatoria, etc.”