Question

Grey spots of Oat are caused by deficiency of:
A. Cu
B. Zn
C. Mn
D. Fe

Answer 1

Essential elements are those elements which perform several functions in the plant. They carry out various metabolic activities in the body. Some of them are essential for structural properties of the cell.

Complete answer:
Cu, Zn, Mn and Fe are essential elements.

Cu (Copper) is essential for metabolic activities in the plant. It is involved in oxidation- reduction reactions in the plant.

Zn (Zinc) acts as a cofactor for carboxylase enzymes. It activates the carboxylase enzyme. It is responsible for synthesis of auxin hormone in plant,

Fe (Iron) acts as an important element in ferredoxin and cytochrome. It is essential for the formation of chlorophyll. It acts as a cofactor for catalase enzymes.
Cu, Zn and Fe element’s deficiency does not lead to grey spots of Oat disease in plants.

Mn (Manganese) is required by leaves and seeds. It acts as an activator of enzymes such as oxidase, dehydrogenase and kinases. It is also involved in respiration, photosynthesis and nitrogen metabolism. It is responsible for splitting of water in the light phase of photosynthesis.

The deficiency of Manganese leads to a grey spot of Oat disease. In this condition, the brown elongated speck and streaks are found in panicles. Development of the root system is poor. The brown-greyish lesions are also found on leaves. These lesions coalesce and are responsible for collapsing the leaf. Interveinal chlorosis is found which leads to yellowness between the veins in the leaf.

Hence, The correct answer is option (C).

Note: Manganese (Mn) and Magnesium (Mg) are two different elements. Magnesium is a macroelement. Whereas manganese is a microelement. Magnesium does not cause a grey spot of Oat disease in plants.