Mineral Toxicity

That old idiom, “Too much of a good thing is bad”, is quite relevant to the topic being discussed. Consider this, love of chocolates tends to be universal, tales of how dark chocolate helps with reducing cholesterol levels and acts as a natural antidepressant among others are well heard of. However, we have been told from a young age on how consuming chocolates in excess leads to numerous ill effects, including high blood pressure, and weight gain. In other words, it is toxic in large quantities. So there is a delicate balance to be maintained between too much and too little.

What is Mineral Toxicity?

Plants work quite the same way. In fact, the whole world works on a careful balance, and every living being in this same world must obey the law of balance. The seven essential micronutrients have to be maintained in an exact proportion. From this, a careful conclusion can be drawn that too much leads to toxicity while too little gives rise to deficiency, which has been discussed earlier.

Mineral elements hold diverse functions in all plants, including electron carriers, enzyme activation, providing osmoticum for turgor and growth, maintaining charge balance, structural components and more.

Effects of Mineral Toxicity

The effects of mineral nutrient deficiencies in plants result in roots and leaf cessation, reduced growth,  massive disruption in cell and cell walls, reduced branching, small changes in the pH of the cytosol, an inability of an enzyme to align correctly with a reactant, stunting, abnormal thickening, and darkening of roots, iron chlorosis, oxidative stress, chlorosis, destruction of chloroplasts, and death of cells and tissue.

This raises the question, how is this delicate balance or exact proportion determined? There lies a straightforward answer for this; the concentration of the mineral ion in tissue decreases the dry weight of tissues by 10 per cent and is said to be toxic. These concentrations do vary among different plants since every plant has different nutritional needs, varying weights, energy requirements, and more.

Also, another issue to be considered is that an excess intake of one element inhibits the uptake of another element. For instance, the presence of manganese toxicity is observed by the appearance of brown spots encompassed by chlorotic veins. Here the manganese competes with magnesium and iron for absorption and also hinders calcium translocation in the shoot apex of the plant. Consequently, the abundance of manganese in plants induces a deficiency of iron, copper, and calcium. So it is apparent that toxicity and deficiency are closely interlinked.

To learn more about mineral toxicity, download BYJU’S-The Learning App.