(i) Phosphorus is an important constituent of energy rich nucleotides like ATP. As inorganic phosphate in ATP is needed in protein synthesis and in the production of nucleic acids, DNA and RNA. Deficiency symptoms of phosphorous are more prominent on aerial parts. The most important visible symptoms are reduction in leaf expansion and leaf surface area. There is a distinct fall in number of leaves on the plant.
(ii) Iron is an essential mineral elements required for normal growth of plants. Iron is required for chlorophyll biosynthesis. Hence, in deficiency of iron, yellow or white areas are seen on youngest leaves. Older leaves remain green, because they already have chlorophyll in them.
(iii) Chloride helps in gas exchange, photosynthesis and protection of plant against diseases. Deficiency of chlorine leads to leaf mottling and leaflet blade tip wilting along with chlorosis.
