Nutrient Requirements in Plants

 
 
2.2  Nutrient Requirements in Plants
 
1. Macronutrient
 
Macronutrient Functions
Nitrogen
  • Synthesises protein, chlorophyll, enzyme and nucleic acid
  • Helps the growth of branches and leaves
  • Increases the production of fruits and seeds
Phosphorus
  • Synthesises protein and nucleic acid
  • Promotes cell division for the production of flowers and fruits
Potassium
  • Synthesises protein
  • Promotes plant cell division
  • Strengthens resistance to infectious diseases
Magnesium
  • An important component in chlorophyll
Calcium
  • Synthesises spindle fibres during cell division
  • Helps growth of meristem at tips of shoots and roots
Sulphur
  • Synthesises protein and chlorophyll
  • Helps development of fruits
  • Promotes plant cell division
Oxygen
  • Involved in plant cell respiration to produce energy

Carbon

Hydrogen

  • Builds sugar or starch during photosynthesis
  • Builds cellulose
 
2. Micronutrients
 
Micronutrient Functions
Boron
  • Synthesis chlorophyll and cell wall
  • Helps the formation of fruits and seeds
Iron
  • Helps growth of young tree parts
  • Helps cell respiration
Copper
  • Involved in photosynthesis and respiration
Molybdenum
  • Synthesises protein
  • Helps the growth of plants
Manganese
  • Involved in photosynthesis and respiration
  • Helps formation of amino acid
Zinc
  • Helps synthesis of protein and formation of chlorophyll
  • Helps the formation of leaves
 
3. Effects of nutrients deficiency in plant growth
 
Healthy plant
  • Normal plant growth 
  • Strong stem 
  • Leaves at the top are small and light green
  • Leaves at the bottom are bigger and dark green
  • The production of flowers and fruits is normal
  • The growth of roots is normal 
Plant with nitrogen deficiency
  • Stunted plant growth 
  • Weak stem 
  • Leaves at the top are smaller and fall easily
  • Leaves at the bottom are pale green or yellow (chlorosis)
  • The production of flowers and fruits is stunted
  • The growth of roots is normal
Plant with phosphorus deficiency
  • Stunted plant growth; slow to grow and mature
  • Weak stem
  • Leaves at the top are smaller and purplish
  • Leaves at the bottom are bluish-green, curled and with brown edges
  • The production of flowers and fruits stops
  • The growth of roots deteriorates
Plant with potassium deficiency
  • Stunted plant growth; dies before reaching maturity 
  • Weak stem
  • Leaves at the top have brown spots, curled ends and chlorosis
  • Leaves at the bottom wilt and have dead tissues around the edges
  • The production of flowers is reduced, and the production of fruit stops
  • The growth of roots is reduced