Micronutrients:
The nutrients that are required by the plants in smaller quantities are termed as micronutrients. There are eight elements which are termed as micronutrients. These eight micronutrients include iron, zinc, molybdenum, manganese, boron, copper, cobalt and chlorine.

Iron: Iron is essential for the production of chlorophyll. Iron is a fundamental component of many enzymes associated with nitrogen reduction and fixation, energy transfer and lignin formation. Iron is associated with sulfur in plants to form compounds that catalyze other reactions. Lipoxygenases is a very common example of iron containg enzyme involved in deoxygenation of polyunsaturated fatty acids in plant.

Zinc: Zinc is an important component of various enzyme systems for protein synthesis, energy production and growth regulation. Zinc is essential for the transformation of carbohydrates and regulates the consumption of sugars. Zinc is essential for proper mobility of solutes and essential nutrients in plants. Few common examples of Zn containing enzymes are alcohol dehydrogenase, Cu- Zn superoxide dismutase, carbonic anhydrase, and RNA polymerase.

Molybdenum: Molybdenum is an essential component of the enzymes relating to nitrogen fixation by bacteria. Molybdenum is involved in protein synthesis, nitrogen metabolism and sulfur metabolism. Molybdenum plays a significant role in pollen formation.

Manganese: Manganese has a significant role to play in nitrogen metabolism, photosynthesis and other plant metabolisms. Manganese functions with the enzyme systems involved in carbohydrates breakdown.

Boron: Boron is essential for cell wall formation, production of sugar and carbohydrates. Boron helps in seed, fruit and grain development.

Copper: Copper is essential for reproductive growth. Copper is essential for the utilization of proteins and helps in root metabolism. It is essential for the metabolism of carbohydrate and nitrogen metabolism and is required for lignin synthesis needed for the strength of cell wall.

Cobalt: Cobalt is essential for nitrogen fixation and plays a vital role in protein synthesis.

Chlorine: Chlorine plays an important role in plant metabolism. It is essential for stomatal opening and electrical charge balance in physiological functions in plants. Further, it restricts wilting.

Water: Water is one of the most essential factors required for the growth of plants. A majority of growing plants contain as much as 90% water. Water plays a crucial role for efficient photosynthesis, respiration, transpiration and transportation of minerals and other nutrients through the plant. Water is responsible for functioning of opening of stomata in leaves and is also the source of pressure for the directed growth of roots through the soil. The role of water in plant growth is emphatically summarized in Table 1.