Toxicity and Antagonism of Minerals

Toxicity of Micronutrients : A mineral ion is considered toxic when its concentration in the tissue reduces dry weight by 10% or more. The toxicity of one element can interfere with the uptake of another -- for example, excess manganese competes with iron and magnesium for uptake, and also inhibits the translocation of calcium to the shoot apex, so that manganese toxicity ends up producing the deficiency symptoms of calcium, magnesium and iron simultaneously, even though none of those three is actually in short supply in the soil. This general phenomenon, where the …