Which of the following are nitrogen-fixing plants?
- 1.Alfalfa
- 2.Amaranth
- 3.Chickpea
- 4.Clover
- 5.Purslane (Kulfa)
- 6.Spinach
Select the correct answer using the code given below:
Answer & explanation
Answer: (a) 1, 3 and 4 only
Only alfalfa, chickpea and clover fix nitrogen, because they are legumes. Legume roots carry nodules housing Rhizobium bacteria that turn nitrogen from the air into a form the plant can use. Amaranth, purslane and spinach are not legumes.
- ✓ 1. Alfalfa (lucerne) is a legume with its own Rhizobium partner, Rhizobium meliloti, in nodules on its roots.
- ✗ 2. Amaranth is a leafy green and grain crop, not a legume, so it has no Rhizobium root nodules.
- ✓ 3. Chickpea (gram) is a pulse and a legume crop, so its root nodules host nitrogen-fixing Rhizobium.
- ✓ 4. Clover is a legume; its roots form nodules with Rhizobium bacteria (the clover group).
- ✗ 5. Purslane (kulfa) is a leafy vegetable, not a legume, and does not fix nitrogen.
- ✗ 6. Spinach is a leafy vegetable, not a legume, and does not fix nitrogen.
Remember · Nitrogen fixers here are legumes: alfalfa, chickpea, clover. Rhizobium in root nodules does the fixing. Leafy greens such as spinach, amaranth and purslane are not legumes.
📘 Read it in NCERT: Class 11 Fundamentals of Physical Geography, Ch 5 (practise this chapter)
Sources
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 5 “Rhizobium, a type of bacteria, lives in the root nodules of leguminous plants and fixes nitrogen beneficial to the host plant.”
- NIH National Library of Medicine (PMC), Symbiotic nitrogen fixation for sustainable chickpea yield and prospects for genome editing in changing climatic situations ↗ “Chickpea ( Cicer arietinum L.) is a vital/essential legume crop valued for its nutritional, agricultural, and economic importance”
- USDA Natural Resources Conservation Service, Inoculation of Legumes ↗ “Alfalfa Group (Rhizobium meliloti) Alfalfa Black medic Burclover Button clover White sweetclover Yellow sweetclover Clover Group (Rhizobium trifolii) Alsike clover Crimson clover Red clover White clover”
Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·