Question

Which of the following is a beneficial element?
A. Na
B. Co
C. Si
D. All of the above

Answer 1

Hint: Plants require water, minerals and other nutrients from soil in order to survive. The soil contains a lot of minerals, and these mineral elements can be defined as inorganic elements which are essential for all life processes.

Complete Answer:
Minerals should be present in adequate amounts as deficiency of minerals could lead to abnormalities in the metabolic functions. At present, around 105 minerals have been discovered and out of these plants can absorb only 60 to 65 minerals. On the basis of quantitative requirements, minerals can be divided into two,
1. Macrominerals
2. Microminerals

- Sodium or Na is a beneficial element as it can help in metabolism and synthesis of chlorophyll in plants. But high levels of sodium in soil can lead to salinity problems, thus the level of sodium must be monitored well.
- Cobalt or Co is an essential component of various enzymes. Cobalt has an effect on both metabolism and growth of plants. Therefore, it is considered a beneficial element.
- Silicon or Si has been proven to be a non-beneficial element for the higher plants but it has beneficial effects on growth of crops like barley, wheat, rice and cucumber. Silicon is not critical for all plants, but can help in improving the growth and yield of the plant.

Thus, the correct option is D) All of the above.

Additional information: Elements such as aluminium, silicon, selenium, cobalt, and sodium are examples of beneficial elements as they are not critical for all plants, but their presence helps in improving the growth and yield of the plant.

Note: The criteria to determine if a mineral is essential or not for a plant is,
- Their deficiency can lead to stunted growth, cell senescence, insufficient chlorophyll in leaves, etc.
- Presence of potassium increases the quality of vegetables and fruits.
- Potassium, magnesium and other elements are involved directly in the metabolism of plants.
- Minerals like phosphorus and magnesium are required for growth, reproduction and development of the plant.