Element 

Discoverer 

Year

Discoverer of Essentiality

Year

C

** 

** 

De Saussure

1804

H 

Cavendish 

1766 

De Saussu re 

1804

O 

Priestley 

1774 

De Saussure 

1804

N 

Rutherford 

1772 

De Saussure 

1804

P 

Brand 

1772 

Ville 

1860

S 

** 

** 

vonSachs, Knop 

1865

K 

Davy 

1807 

vonSachs, Knop 

1860

Ca 

Davy 

1807 

vonSachs, Knop 

1860

Mg 

Davy 

1808 

vonSachs, Knop 

1860

Fe 

** 

** 

vonSachs, Knop 

1860

Mn 

Scheele 

1774 

McHargue 

1922

Cu 

** 

** 

Sommer 
Lipman & MacKinnon 

1931
1931

Zn 

** 

** 

Sommer & Lipman 

1926

Mo 

Hzelm 

1782 

Amon & Stout 

1939

B 

Gay Lussac & Thenard

1808 

Sommer & Lipman 

1926

Cl 

Scheel 

1774 

Stout 

1954

2.  Helps in membrane stability, maintenance of chromosome structure.

3.  Activator of enzymes (phospholipase, argine kinase, adenosine triphosphates).

4.  Acts as a detoxifying agent by neutralizing organic acids in plants.
 

2.  The young leaves of new plants are affected first.  These are often distorted, small and abnormally dark green.

3.  Leaves may be cup-shaped and crinkled and the terminal buds deteriorate with some breakdown of petioles.

4.  Root growth is markedly impaired; rotting of roots occurs.

5.  Desiccation of growing points (terminal buds) of plants under severe deficiency.

6.  Buds and blossoms shed prematurely.

7.  Stem structure weakened.
 

2.  An activator of many enzyme systems involved in carbohydrate metabolism, synthesis of nucleic acids, etc.

3.  Promotes uptake and translocation of phosphorus.

4.  Helps in movement of sugars within plant.

2.  Leaves usually small, brittle in final stages and curve upwards at margin.

3.  In some vegetable plants, chlorotic spots between veins, and marbling with tints of orange, red and purple.

4.  Twigs weak and prone to fungus attack, usually premature leaf drop.
 

2.  Involved in the metabolic activities of vitamins, biotin, thiamine and coenzyme A.

3.  Aids stabilization of protein structure.
 

2.  Shoot growth is restricted, flower production often indeterminate.

3.  Stems are stiff, woody and small in diameter.

2.  Essential component of many enzymes.

3.  Plays an essential role in nucleic acid metabolism affects RNA metabolism or chloroplasts.
 

2.  In severe cases, the entire leaf, veins and interveinal areas turn yellow and may eventually become bleached.

2.  Involved in the plant's respiratory process.

3.  Activates enzymes concerned with the metabolism of nitrogen and synthesis of chlorophyll.

4.  Controls the redox potential in plant cells during the phases of light and darkness.
 

2.  Greyish areas appear near the base of the younger leaves and become yellowish to yellow orange.

3.  Symptoms of deficiency popularly known in oats as "grey speck", in field peas as "marsh spot", in sugarcane as "streak disease''.

2.  Ability to complex with various polyhydroxy-compounds.

3.  Increases permeability in membrane and thereby facilitates carbohydrate transport.

4.  Involved in lignin synthesis and other reactions.

5.  Essential for cell division.

6.  Associated with the uptake of calcium and its utilization by plants.

7.  Regulates potassium/calcium ration in plants.

8.  Essential for protein synthesis.
 

2.  The leaves have a thick texture, sometimes curling and becoming brittle.

3.  Flowers do not form and root growth is stunted.

4.  "Brown heart" in root crops characterized by dark spots on the thickest part of the root or splitting at center.

5.  Fruits such as apples develop "internal and external cork" symptoms.

2.  Constituent of nitrate reductase and nitrogenase.

3.  Required by Rhizobia for nitrogen fixation.

2.  In cauliflower, the leaf tissues wither leaving only the midrib and a few small pieces of leaf blade ("whip-tail").

3.  Molybdenum deficiency is markedly evident in leguminous plants.
 

2.  Constituent of many compounds found in fungi and bacteria.

3.  Stimulates the activity of some enzymes and influences carbohydrate metabolism and water holding capacity of plant tissue.
 

2.  Increases growth and development of all living tissues.

3.  Improves the quality of leafy vegetables and fodders and the protein content of food grains. 
 
 

2.  Appearance of a light-green to pale-yellow color on the older leaves, starting from the tips.  This is followed by death and/or dropping of the older leaves depending upon the degree of deficiency.

3.  In acute deficiency, flowering is greatly reduced.

4.  Lower protein content. 

2.  Constituent of certain amino acids.

3.  Necessary for cell division, a constituent of chromosomes; stimulates root development.

4.  Necessary for meristematic growth; seed and fruit development; stimulates flowering.
 

2.  In acute deficiency, occasional purpling of leaves and stems; spindly growth.

3.  Delayed maturity and lack of or poor seed and fruit development.

2.  Assists carbohydrate translocation; synthesis of protein and maintenance of its stability; membrane permeability and pH control; water utilization by stomatal regulation.

3.  Improves utilization of light during cool and cloudy weather and thereby enhances plant ability to resist cold and other  adverse conditions.

4.  Enhances the plant's ability to resist diseases.

5.  Increases size of grains or seeds and improves the quality of fruits and vegetables. 
 

2.  Slow and stunted growth of plants.

3.  Stalks weak, and plants lodge easily.

4.  Shriveled seeds or fruits.

2.  Essential component of a variety of metallo-enzymes-carbonic anhydrase, alcohol dehydrogenase, etc.

3.  Plays a role in nucleic acid and protein synthesis.

4.  Assists the utilization of phosphorus and nitrogen in plants.

2.  In maize, from light yellow striping to a broad band of white or yellow tissue with reddish purple veins between the midrib and edges of the leaf, occurring mainly in the lower half of the leaf.

3.  In wheat, a longitudinal band of white or yellow leaf tissue, followed by interveinal chlorotic mottling and white to brown necrotic lesions in the middle of the leaf blade; eventual collapse of the affected leaves near the middle.

4.  In rice, after 15-20 days of transplanting, small scattered light yellow spots appear on the older leaves which later enlarge, coalesce and turn deep brown; the entire leaf becomes rust-brown in color and dries out within a month.

5.  In citrus, irregular interveinal chlorosis; terminal leaves become small and narrowed (little-leaf); fruit-bud formation is severely reduced; twigs die back.
 

2.  Promotes formation of vitamin A in plants.
 
 

2.  In citrus, die back of new growth; exanthema  pockets of gum develop between the bark and the wood; the fruit shows brown excretions.