Essential Minerals

Introduction

The majority of minerals are important minerals required by plants in soil that may be absorbed by plants through their roots. In fact, more than sixty of the 105 elements discovered so far have been found in plants.Some plants accumulate heavy and toxic elements such as selenium, while others gather gold and a few plants close to atomic test locales collect radioactive strontium.

Criteria for Importance

The following are the factors for determining whether or not an element is essential:

(a) The element must be absolutely required for normal development and reproduction to occur.

Plants don’t complete their life cycle or set seeds without even a trace of the component.

(b) The element’s need must be unique and cannot be replaced by another element. In other words, a deficit of one element cannot be compensated by the addition of another.

(c) The element must play a direct role in the plant’s metabolism.

Based on their quantitative needs, these elements are further classified into two major categories.

• Macronutrients 
• Micronutrients 

• Macronutrients are found in enormous levels in plant tissues (in excess of 10 m mole /Kg–1 dry matter)
• C, H, O, N, P, S, K, Ca, and Mg are among the macronutrients
• Carbon, hydrogen and oxygen are the most common elements 
• Micronutrients, often known as non essential trace elements, are only required in tiny levels (less than 10 m mole/ Kg –1 dry matter). Iron, manganese, copper, molybdenum, zinc, boron, chlorine and nickel are among them
• There are some helpful elements, such as sodium, silicon, cobalt and selenium, in addition to the 17 essential elements listed above

On the basis of their various roles, essential elements can also be divided into four major categories. 

These are the categories: 

(i) Essential elements as biomolecule components and thus cell structural elements (e.g., C, H, O, N, P, S, K, Ca and Mg).

(ii) Essential elements found in energy-related chemical compounds in plants (for example, magnesium in chlorophyll and phosphorus in ATP).

(iii)Essential components that activate or inhibit enzymes.

Both ribulose bisphosphate carboxylase-oxidase and phosphoenolpyruvate carboxylase are activated by magnesium are important enzymes in photosynthetic carbon fixation; during nitrogen metabolism, Zn2+ activates alcohol dehydrogenase and Mo activates nitrogenase.

(iv) The osmotic potential of a cell can be altered by some critical components.

Role of some essential elements-

Calcium: 

• Plants take calcium in the form of calcium ions (Ca2+) from the soil
• Meristematic and differentiating tissues both require calcium
• It is employed in the formation of cell walls during cell division, primarily as calcium pectate in the middle lamella. It’s also required for the mitotic spindle to develop
• It builds up in elder leaves
• It plays a role in the proper functioning of cell membranes. It regulates metabolic activity by activating specific enzymes

Magnesium: 

• It is in the form of divalent Mg2+ and is absorbed by plants
• It activates the enzymes involved in respiration, photosynthesis and DNA and RNA production. Magnesium is a component of chlorophyll’s ring structure and aids in ribosome structure maintenance

Sulphur: 

• It is obtained by plants in the form of sulphate SO4 . 
• Sulphur is found in two amino acids, cysteine and methionine, and is a key component of a variety of coenzymes,essential  vitamins (thiamine, biotin, Coenzyme A) and ferredoxin

Iron:

• Ferric ions (Fe3+) are used by plants to get iron. In comparison to other micronutrients, it is required in higher amounts
• It’s a crucial component of proteins like ferredoxin and cytochromes that help move electrons. During electron transport, it undergoes reversible oxidation from Fe2+ to Fe3+
• It activates the catalase enzyme, which is required for the production of catalase

Manganese 

• It is absorbed as manganese ions (Mn2+) throughout the body
• Numerous compounds engaged with photosynthesis, breath, and nitrogen digestion are initiated by it
• Manganese’s most well-known role is in the splitting of water to release oxygen during photosynthesis

Zinc:

• Zinc is a non-essential trace element obtained by plants as Zn2+ ions. It stimulates a wide range of enzymes, including carboxylases
• It’s also required for auxin synthesis

Copper: 

• It is caught up as cupric particles (Cu2+)
• It is required for plant metabolism to function properly
• It is reversibly oxidised from Cu+ to Cu2+ and is connected with particular enzymes engaged in redox processes, just as iron

Boron:

• It is absorbed as BO3 or BO4  in the body
• Boron is needed for Ca2+ uptake and utilisation, membrane function, pollen germination, cell elongation, cell differentiation, and glucose translocation, among other things
• Plants get molybdenum as molybdate particles  MoO2 2+
• It is a component of various enzymes involved in nitrogen metabolism, including nitrogenase and nitrate reductase

Phosphorus: 

• It is absorbed by plants in the form of phosphate ions from the soil (either as H PO 2  or HPO4 )
• All phosphorylation activities require phosphorus, which is found in cell membranes, some proteins and all nucleic acids and nucleotides

Potassium:

• It  is absorbed as the ion potassium (K+)
• This is needed in greater concentrations in the meristematic tissues, buds, leaves and root tips of plants
• Potassium helps with the upkeep of an anion-cation balance in cells and is associated with protein union, stomata opening and shutting, catalyst enactment and cell bloat
• It can be used to determine the concentration of solutes and the anion-cation balance in cells. It’s required for the water-splitting process to happen

Conclusion :

Essential elements serve a variety of purposes. They are involved in a variety of metabolic activities in plant cells, including cell permeability, osmotic concentration of cell sap, electron transport systems, buffering action, enzymatic activity and serve as a key source of energy macromolecule and co-enzyme components.