Question

A biofertilizer used in paddy fields is :
1. Azolla pinnata
2. Bacillus thuringiensis
3. Rhizobium meliloti
4. Thermus aquaticus

Answer 1

Correct Answer - Option 1 : Azolla pinnata

Concept:

• 'Biofertilizer' is a substance which contains living microorganism which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant. Biofertilizers are not fertilizers.
• Fertilizers directly increase soil fertility by adding nutrients. Biofertilizers add nutrients through the natural processes of fixing atmospheric nitrogen, solubilizing Phosphorus, and stimulating plant growth through the synthesis of growth-promoting substances.

Explanation:

• The major sources of Biofertilizers include Algae, Fungi, Cyano-bacteria & pteridophyte like Azolla Pinnata.
• Azolla pinnata serves as a great biofertilizer for paddy crops (rice).
• It increases the nutrient uptake and grain yield of rice.

     

• Bacillus thuringiensis is used as a biopesticide. It is a vector used for preparing genetically modified organisms that are specific pest resistant. Crop prepared using Bacillus thuringiensis is BT Cotton for control of pest Bollworm.
• Rhizobium meliloti is gram-negative nitrogen-fixing bacteria. It forms a symbiotic relationship with the roots of plant genera like Medicago, Melilotus, and Trigonella and fixes the atmospheric nitrogen for them.
• Thermus aquatics is bacterial species that can survive extremely high temperatures. It produces a heat-resistant enzyme called Taq Polymerase that is used in the process of Polymerase chain reaction (PCR).