Question

Given below are two statements:
Statement (I): Mycorrhiza soil fungi, solubilizes potassium (K) in soil and makes available to plants on which they live.
Statement (II): The mycorrhizae that live inside roots are Phoma and Rizoctonia.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are true.
• B. Both Statement (I) and Statement (II) are false.
• C. Statement (I) is true but Statement (II) is false.
• D. Statement (I) is false but Statement (II) is true.

Hint:

Mycorrhizae are primarily associated with the uptake of immobile Phosphorus (P), not Potassium (K).
The most common endomycorrhizal fungi belong to the phylum Glomeromycota (such as the genus Glomus), whereas Phoma and Rhizoctonia are generally plant pathogens.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Mycorrhizae are beneficial symbiotic associations formed between specialized soil fungi and the roots of most terrestrial vascular plants.
This mutualistic relationship enhances the plant's nutrient uptake capacity in exchange for photosynthetic carbohydrates.

Step 2: Detailed Explanation:
Let us analyze both statements to evaluate their scientific accuracy:
- Statement (I): Mycorrhizal fungi are famous for mobilizing and solubilizing soil phosphorus (P), which is highly immobile in soil, as well as zinc and copper.
They do not play a primary role in solubilizing potassium (K) to make it available to plants.
Potassium solubilization is carried out by specialized potassium-solubilizing bacteria (KSB) such as Bacillus mucilaginosus.
Therefore, Statement (I) is incorrect because it misattributes potassium solubilization to mycorrhizae.
- Statement (II): The mycorrhizae that live inside root cells are called endomycorrhizae (specifically Arbuscular Mycorrhizae or AM fungi).
The primary genera of AM fungi are Glomus, Gigaspora, Acaulospora, and Sclerocystis.
In contrast, Phoma and Rhizoctonia are well-known, destructive soil-borne plant pathogenic fungi that cause diseases such as root rot, damping-off, and stem cankers in agricultural crops.
While a few specialized species of Rhizoctonia can form mycorrhizal-like associations in orchids, they are not the standard endomycorrhizae that live inside agricultural crop roots.
Therefore, Statement (II) is incorrect.
Since both statements are incorrect, option (B) is the correct choice.

Step 2: Final Answer:
Both Statement (I) and Statement (II) are false.