Question

Among the following microbes which is helpful for the absorption of phosphorus from the soil

• A. Nostoc
• B. Glomus
• C. Rhizobium
• D. Azospirillum

Hint:

Mycorrhizae act as extended root systems.
They are particularly critical for absorbing immobile soil nutrients like phosphorus, which do not easily diffuse toward plant roots.

Answer 1

The Correct Option is B

Step 1: Separate nitrogen helpers from phosphorus helpers.
Nostoc, Rhizobium and Azospirillum are all associated with fixing atmospheric nitrogen for the plant, not phosphorus uptake.
Step 2: Recall the phosphorus specialist.
Glomus is a fungus that forms arbuscular mycorrhizal associations with roots, sending its hyphae deep into the soil to draw out phosphorus.
Step 3: Recall the trade the plant makes in return.
The plant supplies the fungus with sugars from photosynthesis in exchange for this phosphorus supply, confirming Glomus as the phosphorus-absorption partner.
Final answer: Option 2, Glomus.