Name

Symbol

Atomic number

Atomic weight

Classification

Importance to plants

Nitrogen

N

7

14.01

Macronutrient

Constituent of chlorophyll, amino acids and nucleic acids

Potassium

K

19

39.10

Macronutrient

Stimulates a number of enzymatic activities; involved in opening of stomata

Calcium

Ca

20

40.08

Macronutrient

Contributes to cell membrane stability, cell wall rigidity, and cell division

Magnesium

Mg

12

24.31

Macronutrient

A major component of chlorophyll; activates enzymes for respiration, photosynthesis, and DNA synthesis

Phosphorus

P

15

30.97

Macronutrient

Component of membrane phospholipids, nucleic acids, sugar phosphates, ATP, & ADP

Sulfur

S

16

32.07

Macronutrient

Component of some amino acids and some coenzymes for the plant’s metabolic and synthetic processes

Chlorine

Cl

17

35.45

Micronutrient

Involved in water-splitting reaction in photosynthesis, cell division, osmoregulation, and closure of stomata

Iron

Fe

26

55.85

Micronutrient

Component of proteins involved in photosynthesis, respiration, & nitrogen fixation; required for chlorophyll synthesis

Boron

B

5

10.81

Micronutrient

Involved in sugar transport, cell wall synthesis, carbohydrate metabolism, & pollen tube growth

Manganese

Mn

25

54.94

Micronutrient

Required for photosynthetic evolution of oxygen; cofactor in many enzymes

Zinc

Zn

30

65.39

Micronutrient

Component of many enzymes; involved in gene regulation

Copper

Cu

29

63.55

Micronutrient

Cofactor of enzymes involved in redox reactions; involved in cell wall lignifications

Molybdenum

Mo

42

95.94

Micronutrient

Catalyst for nitrogen metabolism

Nickel

Ni

28

58.69

Micronutrient

Component of urease and hydrogenase; involved in mobilization of nitrogenous compounds