Roles of Nutrients in Plants - Sonic Essentials

Each essential element has at least one specifically defined role in plant growth so that plants fail to grow and reproduce normally in its absence. Most of the essential elements have several functions in the plant.

Carbon, from carbon dioxide (CO₂) in the atmosphere, is assimilated by plants in the photosynthetic process. It is a component of organic compounds such as sugars, proteins, and organic acids. These compounds are used in structural components, enzymatic reactions, and genetic material.

Oxygen, derived from CO₂, also is a part of organic compounds such as simple sugars. Atmospheric oxygen is necessary for all oxygen-requiring reactions in plants including nutrient uptake by roots.

Hydrogen derived from water (H₂O) is incorporated into organic compounds in the photosynthetic process. Hydrogen is involved in electrochemical reactions and maintain electrical charge balances across all membranes.

Nitrogen (N)

essential role in the synthesis of chlorophyll
essential part of forming plant proteins
influences tillering and seed formation in grasses

Phosphorus (P)

vital role in energy storage and transfer during photosynthesis and respiration
required for cell division and enlargement, especially at growing points
may help improve tolerance to drought

Potassium (K)

photosynthesis and respiration
protein synthesis
may improve tolerance to diseases
activates enzyme systems
can improve tolerance to cold and drought
may reduce lodging

Sulphur (S)

assists nitrogen fixation by legumes
important part of amino acids that form proteins
necessary for chlorophyll formation and photosynthesis

Calcium (Ca)

Required for cell division and elongation
Required for cell wall development
Nitrate uptake and metabolism
Activates enzyme activity
Starch metabolism
can help delay leaf senescence and slow down leaf and fruit fall

Magnesium (Mg)

important for chlorophyll
aids phosphate metabolism
aids respiration
aids protein synthesis
important in the formation of seeds with high oil content

Copper (Cu)

Pollination & seed set
Carbohydrate and protein metabolism.
Formation of lignin in plant cell walls which contributes to the structural strength of the cells, and the plant.
A catalyst in photosynthesis and respiration.
It is a constituent of several enzyme systems involved in building and converting amino acids to proteins.
Cu:N Balance: High N uptake in the presence of marginal Cu levels can lead to a reduction of Cu transport into the growing tips of plants
Copper also affects the flavour, the storage ability, and the sugar content of fruits.
may improve tolerance to fungal attack

Zinc (Zn)

Production of Auxins, an essential growth hormone.
Activates enzymes in protein synthesis, plus is involved in the regulation and consumption of sugars
Starch formation
Root development.
Influences the rate of seed and stalk maturation.
It is necessary for the formation of chlorophyll and carbohydrates.
Adequate amounts of zinc aid’s the plant to withstand lower air temperatures.

Manganese (Mn)

important for chlorophyll synthesis, enzyme systems, and carbohydrate and nitrogen metabolism
Photosynthesis

Iron (Fe)

catalyst for chlorophyll synthesis
oxygen carrier

Molybdenum (Mo)

important in nitrogen metabolism and protein synthesis
required in root nodules of legumes for nitrogen fixation

Boron (B)

important in the processes of pollination, fruit and seed set (e.g. legumes), fruit development and quality
important for the translocation of sugars
influences cell wall development
nodule formation in legumes

Chlorine (Cl)

involved in transport of nutrients within plants
helps regulate opening and closing of stomata

Silicon (Si)

contributes to cell wall structure, drought tolerance and tolerance to insects and diseases

The following chart shows nutrient solubility at a range of pH levels. For example, if we look at iron, it becomes more soluble in an acidic soil, and in the case of iron, has a strong influence on soil acidity and solubility of some other nutrients (aluminium is very similar to iron). We can also see phosphorus become less soluble in an acidic soil thus less available to the plant. In fact, using this example, the phosphorus becomes and aluminium phosphate or an iron phosphate product.

In and alkaline soil, most often calcium becomes the dominant element, the phosphate become less soluble between pH 8 and 8.75, often forming calcium phosphate product.

Nutrient antagonism and synergism

An excess of one nutrient can mean a deficiency of another

The aim of nutrient application is to provide an amount of nutrient in a manner which contributes to soil and crop performance. Over application of a nutrient may be wasteful or inhibit soil and crop performance.

Using calcium as an example we can see that this element reacts with numerous other elements being Manganese, phosphorus, zinc, boron, magnesium, iron and potassium. By using soil tests to understand the soil type, we can make informed decisions about rate and frequency of applications and improve management outcome of soils, crops and livestock.