Biology XI:12 Mineral Nutrition(3 Symptoms of Nutrient)

Symptoms of Nutrient's Deficiency and Toxicity of Micronutrients Deficiency Symptoms of Essential Elements Critical Concentration − Concentration of essential elements below which plant growth is retarded Deficiency symptoms are the morphological changes that are indicative of deficiency of certain elements. Deficiency symptoms may depend upon mobility of the element in plant. Actively mobilizing elements such as N, K, Mg are mobilized from older to younger parts of the plant. Hence, their deficiency symptoms appear first in old senescent leaves. Relatively immobile elements such as S, Ca have their deficiency symptoms first seen in younger parts of plant. Deficiency Symptom Caused by Deficiency of Chlorosis (Loss of Chlorophyll) - leads to yellowing of leaves N, K, Mg, S, Fe, Mn, Zn, Mo Necrosis (Death of Tissue) Ca, Cu, K, Mg Inhibition of Cell Division N, K, S, Mo Delayed flowering N, S, Mo Toxicity of Micronutrients Increase in concentration of micronutrients causes toxicity. Any mineral ion concentration that reduces the dry weight of tissues by 10% is considered toxic. Toxicity of one element may lead to deficiency of other elements since the former may inhibit the uptake of latter. For example → Mn competes with Fe, Mg for uptake and also inhibits Ca translocation to shoot apex. Therefore, Mn toxicity symptoms are actually same as deficiency symptoms of Fe, Mg, and Ca.