question_answer 3)

Explain with examples macronutrients, micronutrients, beneficial nutrients, toxic elements and essential elements. 

Answer:

Macronutrients Macronutrients are generally present in plant tissues in large amount (in excess of 10 m mole kg"1 of dry matter). The macronutrients include carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur, potassium, calcium and magnesium. Micronutrients Micronutrients or trace elements, are needed in very small amount (less than 10 m mole kg"1 of dry matter). These include iron, manganese, copper, molybdenum, zinc, boron, chlorine and nickel. Toxic Elements Any mineral ion concentration in tissues, that reduces the dry weight of tissues by about 10% is considered toxic. For example, Mn inhibit the absorption of other elements. Essential Elements The macronutrients including carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur, potassium, calcium and magnesium, which are require directly for the growth and metabolism of the plants and whose deficiency produces certain symptoms in the plants are known as essential elements.