Question

Criteria of essentiality is applicable to
(a)Only microelements
(b)Only macronutrients
(c)Both micro-and macronutrients
(d)All elements found in soil

Answer 1

Hint: Plants require light, water, and about 20 elements to support all their biochemical needs. These 20 elements are essential nutrients for the plants. They help in germination, growth, reproduction, and make the plants pest or insect resistant.

Complete answer:
The criterion of essentiality is applicable to both micro and macronutrients. They are required for the growth and development of plants. Macronutrients are the nutrients that are required in large amounts by all living things. It involves elements like nitrogen, phosphorus, potassium, sulfur, magnesium, and calcium. However, micronutrients are the mineral, vitamin, or other substance that's essential, even in very small quantities, for growth or metabolism. Micronutrients involve iron, manganese, boron, zinc, copper, molybdenum, chlorine, nickel, sodium, cobalt, and silicon.

Additional Information:
Role of Macronutrients-
-Nitrogen is essential for flowers.
-Phosphorus helps in growth and metabolism in plants.
-Potassium helps in the cellular division in roots and other parts of the plant.
-Sulfur is important to supply chlorophyll.
-Magnesium is essential for the germination of seeds.
-Calcium activates enzymes
-Role of Micronutrients-
-Iron helps in the synthesis of chlorophyll.
-Manganese involves photosynthesis, respiration, and nitrogen metabolism.
-Boron is important for cell membrane formation, membrane integrity, and calcium uptake.
-Zinc is essential for internodal elongation.
-Copper is a component of several enzymes.
-Molybdenum helps in reducing nitrates to ammonia.
-Chlorine is involved in osmosis, the ionic balance necessary, and photosynthesis.
-Nickel, Seeds need nickel to germinate.
-Sodium is involved in osmotic (water movement) and ionic balance in plants.
-Cobalt is required in legumes and root nodules of nonlegumes.
-Silicon is found as a component of cell walls and produces stronger, tougher cell walls.
So, the correct answer is ‘both micro-and macronutrients’.

Note: Deficiencies in any of these nutrients, particularly the macronutrients, can adversely affect plant growth. Depending on the precise nutrient, a scarcity can cause stunted growth, slow growth, or chlorosis. Extreme deficiencies may result in leaves showing signs of cell death.