Question

Select the correct choice from the following: (a) Ca (i) Tea yellow disease (b) Zn (ii) Black heart of celery (c) B (iii) Brown heart of turnip (d) Cu (iv) Khaira disease of rice (v) Exanthema of Citrus

• A. (ii) (iv) (iii) (v)
• B. (iv) (ii) (iii) (i)
• C. (ii) (iv) (v) (iii)
• D. (i) (ii) (iv) (iii)

Answer 1

Answer:

A. (ii) (iv) (iii) (v)

Essential elements are divided into two broad categories, based on the quantity in which they are required by plants. Macro-elements and micro-elements. Their ionic forms are respectively called macronutrients and micronutrients. Cations may be absorbed on the surface of negatively charged clay particles. Anions (e.g., nitrate, phosphate, chloride, sulphate, borate) are held to soil particles to a lesser extent. Mineral salts dissolved in soil solution are constantly passing downwards along with percolating (gravitational) water. The phenomenon is called leaching. Leaching is more in case of anions. Macronutrients (Macroelements or major elements) : Which are required by plants in larger amounts.The macronutrients include carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur, potassium, calcium, magnesium. Micronutrients (Microelements or minor elements or trace elements) : Which are required by plants in very small amounts,i.e., in traces.These include iron, maganese, copper, molybdenum, zinc, boron and chlorine. Recent research has shown that some elements, such as cobalt, vanadium and nickel, may be essential for certain plants.