Plant nutrients needed in micro levels are called as micronutrients. Mineral elements comprising of Zinc (Zn), Copper (Cu), Manganese (Mn), Iron (Fe), Boron (B), Molybdenum (Mo) are the essential micronutrients needed for plant growth and development.
Micronutrients are crucial for plant growth and play an important role in balancing crop nutrition. Micronutrients, though needed in minute amounts play an important role in most enzymatic reactions as they act as co factors for enzymes.
Micronutrients help the major elements to perform their functions. If they are not present, the major elements will not be able to perform their duties even if you supply them.
The common roles are overall plant growth, photosynthesis, chlorophyll formation, cell wall development resistance to plant disease, nitrogen fixation, colour of the fruits, sugar transport, fruit textures, the turgidity of the plant, and osmotic balances.