Micronutrients
Essential Micronutrients for Plant Health
The following are micronutrients, which are nutrients needed by the plant only in small amounts:
Zinc (Zn)
Primary role in the plant:
Needed for normal growth and reproduction, essential part of enzyme system related to plant growth
Summary:
Zinc is an essential component of several enzymes in plants. It controls the synthesis of indoleacetic acid, an important plant growth regulator, and it is involved in the production of chlorophyll and protein. Zinc is taken up by plants as the zinc ion (Zn+2).
Deficiency symptoms:
- Decreasing in stem length and a rosetting of terminal leaves.
- Reduced fruit bud formation.
- Dieback of twigs after the first year.
- Mottled leaves and interveinal chlorosis.
Iron (Fe)
Primary role in the plant:
Enhances rich green color, chlorophyll synthesis and photosynthesis
Summary:
Iron is taken up by plants as ferrous ion (Fe+2). Iron is required for the formation of chlorophyll in plant cells. It serves as an activator for biochemical processes such as respiration, photosynthesis and symbiotic nitrogen fixation. Turf, ornamentals and certain trees are especially susceptible to iron deficiency.
Deficiency symptoms:
- Interveinal chlorosis of young leaves — veins remain green except in severe cases.
- Twig dieback.
- In severe cases, death of limbs or plants.
Manganese (Mn)
Primary role in the plant:
Important role in enzyme formation in plant cells and carbon dixode assimilation
Summary:
Manganese serves as an activator for enzymes in plant growth processes, and it assists iron in chlorophyll formation. Plants obtain this nutrient from the soil in the form of manganous ion (Mn+2).
Deficiency symptoms:
- Interveinal chlorosis of young leaves.
- Gradation of pale green color with darker color next to veins.
Copper (Cu)
Primary role in the plant:
Essential role in chlorophyll production, promotes seed production and formation
Summary:
Copper is an activator of several enzymes in plants. It may play a role in production of vitamin A. Deficiency interferes with protein synthesis. Plants take up copper from the soil in the form of cuprous (Cu+) or cupric (Cu+2) ions.
Deficiency symptoms:
- Stunted growth.
- Dieback of terminal shoots in trees.
- Poor pigmentation.
- Wilting and eventual death of leaf tips.
Boron (B)
Primary role in the plant:
Essential for regulation of metabolism and cell division
Summary:
Boron regulates the metabolism of carbohydrates in plants. It is essential for the process by which meristem cells (cells that divide) differentiate to form specific tissues. Boron is taken up by plants as the borate ion (BO3-). Plants differ in their boron needs.
Deficiency symptoms:
- Death of terminal buds, causing lateral buds to develop and producing a “witches broom” effect.
- Thickened, curled, wilted and chlorotic leaves.
- Soft or necrotic spots in fruit or tubers.
- Reduced flowering or improper pollination.
Molybdenum (Mo)
Primary role in the plant:
Essential for nitrogen utilization
Summary:
Molybdenum is taken up by plants as molybdate ions (MoO4-). Molybdenum is an essential micronutrient that enables plants to make use of nitrogen. Without molybdenum, plants cannot transform nitrate nitrogen to amino acids and legumes cannot fix atmospheric nitrogen.
Deficiency symptoms:
- Stunting and lack of vigor.
- Marginal scorching and cupping or rolling of leaves.
Chlorine (Cl)
Primary role in the plant:
Essential for photosynthesis
Summary:
Chlorine is required in photosynthetic reactions. Plants take up chlorine as chloride ion (Cl-).
Deficiency symptoms:
- Wilting followed by chlorosis (yellowing).
- Excessive branching of lateral roots.
- Bronzing of leaves.