Question

‘Khaira disease of rice’ is caused due to the deficiency of
A. Zinc deficiency
B. Boron deficiency
C. Magnesium deficiency
D. All of the above

Answer 1

Hint: The deficiency of both micronutrients and macronutrients in the plants has a significant effect on their growth and development.

Complete answer:
Two types of nutrients are present in the plants which are termed as macronutrients and micronutrients on the basis of their concentration required by the plants.
Deficiency and over concentration of the nutrients both will produce adverse effects on the plants. Macronutrients are those which are needed by the plants in large quantities like carbon, nitrogen, sulphur etc. whereas micronutrients are those which are required by the plants in very small quantities like boron, chlorine, copper, zinc etc.
Zinc is a micronutrient which is present in trace amounts in the plants but plays a major role in the regulation of the metabolic activities of the plant. Deficiency and excess presence of the nutrients leads to diseases in the plant body. Zinc deficiency is responsible for Khaira disease in the rice plant. Some of the symptoms of the disease are:

Discoloration of the leaves
Plant growth is limited and stunted.
Also the contamination with chlorine makes the midrib chlorotic.
Leaves develop yellow color and then brown spots are formed.
Khaira disease in the plants can be cured by applying the zinc sulphate solution to the leaves of the plants.

The correct answer is (A) Zinc deficiency.

Note: Different nutrients have different functions in the body or an organism. Zinc deficiency leads to Khaira disease in rice which affects the plants and will also have an effect on the yield.