-fixing blue-green alga Anabaena which is extensively used in rice cultivation, forms symbiotic association with
Important Questions on Mineral Nutrition
Study the following illustration of nitrogen cycle and identify and in it.
I) Blue-green algae add organic matter to the soil and increase fertility
II) Fungal symbiont of Mycorrhiza facilitates absorption of nitrogen
III) Baculoviruses are not desirable in the IPM program
IV) Azospirillum and Azatobacter are free-living in the air
Assertion Free-living bacteria such as Rhizobium and Frankia can help in the biological fixation of dinitrogen in the roots of angiospermous plants.
Reason Prokaryotes exclusively contain nitrogenase enzyme which can catalyze the oxidation reaction of dinitrogen to glutamate.
The correct answer is:
Rhizobium forms a symbiotic association with roots in legumes and fixes atmospheric nitrogen. Which of the following statement is correct about this process?
Match Column - I with Column - II.
| List-I | List-II | ||
| (a) | Nitrococcus | (i) | Denitrification |
| (b) | Rhizobium | (ii) | Conversion of ammonia to nitrite |
| (c) | Thiobacillus | (iii) | Conversion of nitrite to nitrate |
| (d) | Nitrobacter | (iv) | Conversion of atmospheric nitrogen to ammonia |
Assertion (A):- Some plants growing in rich soils can obtain their nitrogen from insects.
Reason R): - Bacteria inhabiting the root system of Fabaceae plants can fix atmosphere nitrogen.
The correct option among the following is:
The nitrogen cycle is given below. Identify A and B in it.
