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Mineral Nutrition

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Biology

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12
List the criteria for essentiality of elements.

Arnon and Stout gave the following criteria for the essentiality of elements :

1. The essential elements should be necessary for growth and reproduction of the plant. It should be indispensable. The plant should not be able to complete its lifecycle in the deficiency of the element. 

2. The element should not be replaceable and its requirement should be specific. The deficiency of the element should not be met by supplying some other element. 

3. There should be direct involvement of the element in the metabolism of the plant. 


Which pigment is present in the root nodules of legumes ?

Leghaemoglobin.

Name the best known symbiotic nitrogen fixing bacterium.

Rhizobium.

How is nitrogenase enzyme protected ?

The nitrogenase enzyme is very sensitive to the molecular oxygen. It requires anaerobic conditions to work. The leg-haemoglobin in the nodule acts as an oxygen scavenger just meainting the anaerobic condition needed by the enzyme.

What type of condition is created by leghaemoglobin in the root modules of legumes ?

Anaerobic.

What is Hidden hunger in the case of plants?

Hidden hunger refers to a situation in which a crop needs more of a given nutrient yet has shown no deficiency symptoms. The nutrient content is above the deficiency symptom zone but still considerably needed for optimum crop production