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CBSE Gujarat Board Haryana Board

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Class 10 Class 12
All elements that are present in plant need not be essential to its survival. Comment.

All elements present in the plant need not be essential to its survival. For a element to be essential it has to meet all the criteria for essentiality. The criteria for essentiality are :

i. The element must be absolutely esential for supporting the normal growth and reproduction. The plant should be unable to complete its lifecycle in the absene of the element.

ii. The element requirement should be specific and not replaceble by another element. 

iii. The element must be directly involved in the metabolism of the plant. 

Since, all the elements do not meet all the criteria, they are not considered to be essential to the plant. 

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


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.

Which pigment is present in the root nodules of legumes ?


Name the best known symbiotic nitrogen fixing bacterium.


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