Micronutrients reinforce and supplement the strong plant growth and structures provided by major and secondary nutrients. Most micronutrients influence growth. For example, manganese (Mn), iron (Fe) and copper (Cu) all influence photosynthesis, the process whereby plants use sunlight for growth.
- Iron deficiencies are common – for example in seed fruits – where the effect is to reduce production of chlorophyll. As a result, crops struggle and younger leaves develop a severe yellowing or chlorosis.
- Boron (B) is needed for the development of shoots and roots, and is essential during the flowering and fruiting phases of crops.
- Zinc (Zn) is needed for the production of important plant hormones, like auxin. Zinc deficiency leads to structural defects in leaves and other plant organs.
- Molybdenum (Mo) is involved in plant enzyme systems that control nitrogen metabolism.