MCQ
The common Nitrogen-fixer in paddy fields is
- AFrankia
- BRhizobium
- CAzospirillum
- DOscillatoria
✓
Answer
- Azospirillum
Explanation:
Azospirillum is a microaerophilic nitrogen fixer commonly found in association with the roots of cereals and grasses of interest.
It colonizes the root mass and fixes nitrogen in association with plants.
It is the popular nitrogen-fixer used in paddy fields along with Azolla. When a small amount of it is added to the soil, it multiplies into million and is capable of providing up to 20-40kg of nitrogen per hectare per season.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Big holes in Swiss cheese are made by a:
Consider the following statement about $PCR$
→$I.$ Polymerase Chain Reaction $(PCR)$ is a technique of synthesizing multiple copies of the desired gene in vitro
$II.$ This technique was developed by Kary Mullis in $1985$
$III.$ A single $PCR$ amplification cycle involves three basic steps; denaturation, annealing and extension
Which of the statement given above are correct?
Consider the following statements concerning food chains.
→$I$. Removal of $80\; \%$ tigers from an area resulted in greatly increased growth of vegetation.
$II.$ Removal of most of the carnivores resulted in an increased population of deers.
$III.$ The length of food chains is generally limited to $3$ to $4$ trophic levels due to energy loss.
$IV.$ The length of food chains may vary from $2$ to $8$ trophic levels.
Which two of the above statements are correct?
Among the following bio-geochemical cycles which one does not have losses due to respiration?
The scientists involved in discovery of DNA as chemical basis of heredity were:
Parthenocarpic tomato fruits can be produced by:
Which microble is useful in the formation of curd from milk ?
What is the figure given below showing in particular?
Which of the following does not produce sticky ends?
In the evolution from Homo erectus to Homo sapiens one of the following has played a significant role