Match List-I with List-II
| Characteristics | Examples |
|---|---|
| (A) Symbiotic association with roots of leguminous plants | (I) Glomus |
| (B) Fixes atmospheric nitrogen while free living in the soil | (II) Rhizobium |
| (C) Symbiotic association of fungi and plants | (III) Anabaena |
| (D) Cyanobacteria which can fix atmospheric nitrogen | (IV) Azotobacter |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A) - (II), (B) - (IV), (C) - (I), (D) - (III)
(A) Symbiotic association with roots of leguminous plants — this matches (II) Rhizobium. Rhizobium lives in root nodules of legumes and fixes atmospheric nitrogen into forms the plant can use.
(B) Fixes atmospheric nitrogen while free living in the soil — this matches (IV) Azotobacter. Azotobacter (and Azospirillum) fix nitrogen without living inside a plant, enriching the soil.
(C) Symbiotic association of fungi and plants — this matches (I) Glomus. Members of Glomus form mycorrhiza. The fungus takes up phosphorus from the soil and passes it to the plant.
(D) Cyanobacteria which can fix atmospheric nitrogen — this matches (III) Anabaena. Anabaena, like Nostoc and Oscillatoria, is an autotrophic microbe that fixes nitrogen, important in paddy fields.
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.
Fungi are also known to form symbiotic associations with plants (mycorrhiza). Many members of the genus Glomus form mycorrhiza. The fungal symbiont in these associations absorbs phosphorus from soil and passes it to the plant. …
Cyanobacteria are autotrophic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen, e.g. Anabaena, Nostoc, Oscillatoria, etc.”