MACRO
Main Functions
Constituent of amino acids (proteins), nucleic acids, enzymes (Ex. PEPC and RubisCo) and pigments (chlorophil)
Absorbed Form
NH4+ and NO3-
ION Root Contact
Mass Flow
Deficiency
No protein synthesis, Chlorosis of old leaves (chlorofil lack)
Plant Mobility
Mobile
Source
Urea, Ammonium Nitrate and Sulfate, Potassium Nitrate, MAP and DAP
Observations
N accumulated in plant vacuole only in the form of nitrate. The ammonia form is toxic
Main Functions
Phosphoric Ester Component (Ex. ATP, P-glucose, 3-PGA, etc.), nucleic acids, phospholipids (membrane component); root growth (cell multiplication and division)
Absorbed Form
H2PO4-
ION-Root Contact
Diffusion
Deficiency
Old bluish leaves, less growth
Plant Mobility
Mobile
Source
Single and Triple Super phosphate, MAP and DAP, Magnesian Thermophosphate.
Observations
P in the plant is in organic and inorganic form (accumulated in tha vacuole)
Main Functions
Activator of more than 40 enzymes (ex RubisCo); It influences the optimal cellular turgor of guard and adjacent cells, being important in the process of opening the stomata, as well as in the transport of ions (influences the osmotic potential of the plant). Promotes greater Co diusivity in mesophyll cells
Absorbed Form
K+
ION-Root Contact
Diusion (bigest part)
and Mass Flow
Deficiency
Older leaves with yellowish margins may develop into necrosis.
Plant Mobility
Mobile
Source
Potassium Chloride, Sulfate and Nitrate
Observations
High levels of Ca and Mg can influence the availability of K
Main Functions
Constituents of cell walls; Membrane integrity (interconnects phosphate/carboxylic groups of phospholipids).
Ca is part of pectin through Ca pectates, being required for elongation and mitototic division (root growth).
Enzyme activator (alpha-amylase, etc.)
Absorbed Form
Ca2+
ION-Root Contact
Mass Flow and Root interception
Deficiency
Young leaves are wrinkled, with chlorosis that starts at the edges and progresses towards the center
Plant Mobility
Immobile
Source
Limestone and Plaster
Observations
Decreased absorption with high levels of K and Mg
Main Functions
Protein synthesis; enzyme activator (e.g. RubisCo); constituent of chlorophyll; Storage and transfer of ATP; ATP synthesis (substrate for ATPases: Mg-ATP)
Absorbed Form
Mg2+
ION-Root Contact
Mass Flow and Root interception
Deficiency
Interveinal chlorosis in old leaves
Plant Mobility
Mobile
Source
Limestone
Observations
Helps absorb phosphorus
Main Functions
Component of amino acids (cysteine, cystine and methionine), Coenzymes A (linked to the metabolism of carbohydrates, fats and proteins in respiration) proteins (N metabolism) and enzymes (eg nitrogenase).
Absorbed Form
SO42-
ION-Root Contact
Mass Flow
Deficiency
Chlorosis of younger leaves
Plant Mobility
Not very mobile
Source
Plaster, Single Superfosfate and S pastille.
Observations
Sulphur level can be increased
by addition of organic matter
in the soil. Assimilation of N and
S are coordinated.
