Question

Browning of cauliflower takes place due to the deficiency of which one of the following
A. Copper
B. Boron
C. Potassium
D. Manganese

Answer 1

This is a micronutrient. It plays an important role in the formation and stability of the plant cell wall. It is a component of plant reproductive structures.

Complete answer:
Any of the minerals found in the soil can reach the plant via the roots. In fact, more than 60 of the 105 elements discovered so far have been found in different plants. Some plant species are collecting selenium, several are gold, and certain plants developing near nuclear test sites are picking up radioactive strontium. There are techniques that can detect minerals even at a very low concentration. Only a few elements have been found to be completely necessary for plant growth and metabolism on the basis of the essentiality requirements of the material.
These components are further classified into two large groups on the basis of their quantitative criteria. There are: macronutrients and micronutrients. In general, macronutrients are found in vast quantities in plant tissues.
Macronutrients include hydrogen, carbon, oxygen, phosphorus, nitrogen, sulphur, potassium, magnesium, and calcium. Of these, carbon, hydrogen and oxygen are primarily derived from carbon dioxide and water, while the others are consumed from the soil as mineral nutrients.
Micronutrients or trace elements are required in very small quantities. These contain iron, manganese, copper, molybdenum, zinc, boron, chlorine and nickel. In addition to the 17 basic elements, there are other useful elements such as sodium, silicon, cobalt and selenium.
Boron deficiency causes browning in cauliflower. In general, the signs of boron deficiency are evident externally on plants after curd formation. The water-soaked regions appear at the beginning of the stage on the stem and curd. The stem becomes hollow as the plant grows and soaking water tissue covers the inner walls of the cavity. The brown or the pink surfaces are seen on the curd surface at the advanced stage.

Thus, the correct answer is option B. i.e., Boron.

Note: By adding borax, boron deficiency can be controlled. The amount of borax varies according to soil type, pH and deficiency level. Acid soil requires 10-15 kg borax/ha, while large quantities of borax can be required in alkaline soil.