Nitrogen: Plants absorb nitrogen in the form of NO2, NH3, NH4. Nitrogen is essential to the synthesis of protein, coenzyme, nucleic acid (DNA and RNA) and other organic compounds. It is main component of protoplasm and chlorophyll. Nitrogen is helpful in opening and closing of stomata and movement and balance of water. Potassium: It is important to cell growth, growth of leaves, and formation of secondary roots. It requires to sustain viability of protoplasm. It plays an important role in opening and closing of stomata. It is cofactor of enzyme.