Question

Which one of the following is not an essential mineral element for plants
A. Iron
B. Manganese
C. Cadmium
D. Phosphorus

Answer 1

Hint: The essential minerals are those minerals which are required by the plants for their healthy growth and they are further classified as macro (required in large quantities) and micro (required in smaller quantities).

Complete answer: It is possible to separate the basic elements into macronutrients and micronutrients. Macronutrients are called nutrients which plants need in larger amounts. Macronutrients are considered around half of the essential elements. Micronutrients are the ones needed in smaller quantities.
-Iron is a micronutrient and hence is an essential mineral. In plants, iron is involved in chlorophyll synthesis and is important for the preservation of the structure and function of chloroplasts.
-Manganese is a micronutrient and hence is an essential mineral. In-plant tissue, magnesium is the fundamental core of the chlorophyll molecule. Therefore, the lack of chlorophyll results in low and stunted plant growth if Mg is insufficient.
-Cadmium is a very important and significant metal pollutant. Few heavy metals like cadmium, lead, zinc, mercury cause significant metal toxicity in plants.
-Phosphorus is a macronutrient and hence is required by the plant. A vital component of ATP, the "energy unit" of plants, is phosphorus. ATP forms have phosphorus in their structure and procedures during photosynthesis, from the beginning of seedling growth to grain and maturity formation.

Hence, the correct answer is Option C.

Additional information:
Cadmium (Cd) is an extremely poisonous metal for each plant and animal. The presence of Cd in agricultural soils is of concern relating to its entry into the food chain and can cause serious problems. Compounds of Cd are a lot more soluble than the rest of the heavy metals, thus it's promptly absorbed by the plants and accumulates in several edible plants of the plant and through that, it makes an entry in the food chain. Several approaches are being made to avoid the entry of Cd into the food chain. Good plant nutrition is one of the greatest ways to alleviate the damaging effects of Cd on plants and to avoid entry into the food chain. Plant nutrients play a vital role in developing plant tolerance against Cd toxicity and therefore it leads to low Cd accumulation in several plant components.

Note: Macronutrients (nitrogen, phosphorus, sulfur, and calcium), micronutrients (zinc, iron, and manganese), and elements (a useful nutrient) are also very important for plants based on how these nutrients play their role in decreasing the uptake and absorption of cadmium in plants.