Question

The deficiency of which mineral element leads to ‘Whiptail of Brassica’?
(a) Fe
(b) Cu
(c) Mn
(d) Mo

Answer 1

Hint: A silvery-metal having atomic number 42. In 1781, Peter Jacob Hjelm was first isolated from this metal but in 1778 it was first discovered by Carl Wilhelm Scheele. It is often confused with ores of lead.

Complete answer:
The deficiency of Molybdenum may occur in the plants due to its low absorption or its presence is lower in the soil resulting in the limited growth of the plants. The deficiency of Molybdenum may cause diseases that include necrosis, withering of leaves, folding of margins of leaves, lesser plant growth, whiptail of crucifers (Brassica), or loosening of the cauliflower head, less number of grains in maize, etc.
-Molybdenum is responsible for several enzymes that undergo redox reactions. It also involves certain enzymes that undergo nitrogen metabolism.
-The crucifers are the members of the family Brassicaceae that includes the genus Brassica.
The disease of whiptail in Brassica is due to the deficiency of the Molybdenum which is a trace element, also known as microelement.
- The two main symptoms observed under Whiptail of Brassica are: the elongated and narrow middle foliage of plants having dark green or blue color. The other symptom includes the outer large well developed leaves where chlorosis is absent.
-Its deficiency also causes stoppage of apical growth also called blindness.

So, the correct answer is ‘Mo’.

Note:
The deficiency of Iron (Fe) causes various diseases that includes necrosis and chlorosis of the youngest leaves. The deficiency of Copper (Cu) causes diseases that include chlorosis, interveinal necrosis in the newer leaves. The deficiency of Manganese (Mn) causes interveinal necrosis, stunted and limited plant growth.