Macronutrients
Element/Nutrient	Important Roles/Functions	Expected Deficiency Symptoms
Nitrogen (most likely nutrient to be deficient in soil)	wMajor component of amino acids and proteins. wPresent in membranes, organelles, cell walls, nucleotides, nucleic acids, chlorophylls, coenzymes. wBalance of carbohydrates and nitrogenous substances is necessary.	1. Chlorosis, especially in older leaves. 2. Severe cases: leaves turn yellow and die. 3. Possible: leaves turn purple as anthocyanins accumulate in vacuoles. 4. Stem and leaves stunted development. 5. Unable to flower. 6. Excess root development.
Phosphorus (second-most likely nutrient to be deficient in soil)	wComponent of ATP and ADP (essential energy-carrying compounds). wImportant in respiration and energy transfer. wComponent of nucleic acids, nucleoporteins, several essential coenzymes, phospholipids of membranes.	1. Stunted growth of whole plant (small plants, narrow leaves). 2. Stiff but weak stems and leaves. 3. Older leaves yellowed. 4. Dark green color of other leaves. 5. Root system larger but with fewer secondary roots. 6. In older leaves, accumulation of sugars leads to anthocyanins  in vacuoles giving purple tinge to the leaves.
Potassium	wInvolved in osmosis, ionic balance. wInvolved in opening and closing of stomata. wActivator of enzymes. wNecessary for starch formation.	1. Weak, spindly stems and roots. 2. Internodes short. 3. Older leaves are especially affected: chlorotic mottling with, later on, dead spots along margins and dead tips. 4. Leaf margins frequently curled under. 5. Roots more susceptible to disease.
Magnesium	wComponent of chlorophyll (center of molecule). wImportant cofactor for enzymes in respiration and in phosphate metabolism.	1. Older leaves become chlorotic  between the veins  at the tips and margins. Proceeds to younger leaves as deficiency worsens. 2. Some dead spots and reddish color of leaves. 3. Usually does not produce necrotic roots. 4. Root system frequently is overdeveloped. 5. Leaf margins may curl upward, mostly on older leaves.
Calcium	wComponent in pectin compounds of middle lamella. wPresent in organic acids bound to proteins. wPlays a role in nitrogen metabolism and membrane integrity (permeability). wEnzyme cofactor. wComponent of calmodulin (regulator of membrane and enzyme activities).	1. Possible imbalance of iron uptake, particularly with magnesium (young leaves affected first). 2. Tips and margins of leaves become light green and later necrotic. 3. Tips of leaves become limp. 4. Terminal bud often dies. 5. Root and shoot tips often die. 6. Die back occurs first at tips and margins of young leaves and shoots.
Sulfur	wComponent in some amino acids, proteins, and coenzyme A. wCan be absorbed through stomata as gaseous sulfur dioxide. wComponent of iron-sulfur proteins of the electron transport system.	1. Young leaves light green. 2. Veins lighter than intervein area. 3. Sulfur is rarely limiting.
Iron	wComponent of cytochromes and nitrogenase (important for respiration and photosynthesis). wRequired for chlorophyll synthesis.	1. Effects localized on new leaves: chlorosis between veins. 2. Veins remain green. 3. Short, slender roots.
Micronutrients
Element/Nutrient	Important Roles/Functions	Expected Deficiency Symptoms
Boron	wMobile in plant. wEffects flowering, fruiting, cell division, water relations (translocation of sugars), other plant processes.	1.Symptoms appear at top of plant. 2. Terminal buds die, producing “witches broom.” 3. Lateral branches grow, forming “rosettes.” 4. Young leaves thicken; chlorotic, leathery.
Molybdenum	wInvolved in protein synthesis. wRequired by some enzymes that reduce nitrogen. wVisible symptoms in vegetables, cereals, forage grasses. wElement is unavailable to plants grown in highly acidic conditions. wLiming can be used to correct.	1. Cruciferous (cauliflower, etc.) leaves are narrow. 2. Leaves may be pale green and roll up.
Manganese	wImportant in photosynthesis (used in chlorophyll synthesis, photophosphorylation). wUsed in activation of enzymes. wCarbohydrate metabolism. wNot mobile in plants.	1. Interveinal chlorosis in younger leaves (similar to iron deficiency).
Zinc	wEnzyme activator. wDeficient in calcerous soils that are high in phosphorus.	1. Plant leaves are drastically reduced in size. 2.Shortening of internodes (rosette appearance). 3. Young leaves may show interveinal chlorosis. 4. Peach and citrus produce a “mottled leaf” chlorosis. 5. Kalenchoe susceptible to zinc deficiency as a greenhouse plant.
Copper	wImportant in chlorophyll synthesis. wCatalyst for respiration. wCatalyst for carbonydrate and protein metabolism. wSoils with high organic matter content are prone to copper deficiency.	1. Young leaves show interveinal chlorosis, but leaf tip remains green. 2.Over time the blade may become necrotic. 3. Terminal leaves and buds die. 4. Overall stunting of plant.
Chlorine	wDeficiency in the field is rare; usually an excessive level of chlorine is the problem.	1. If deficiency, plants may become stunted and appear chlorotic with some necrosis.
Micronutrients in general.	wGenerally involved with nitrogen metabolism. wComponents of many enzymes. wComponents of chlorophyll and chloroplast membrane. wInvolved in photosynthetic reactions. wInvolved in ionic balance and utilization.	Effects are variable, depending upon which nutrient is deficient.  Symptoms include: 1. Interveinal chlorosis. 2. Necrosis of leaf tips. 3. Abnormal leaf growth. 4. Stunted root growth.

References:

Acquaah, George. Horticulture: Principles and Practices. Prentice Hall, Upper Saddle River, New Jersey, pp. 101-104.

Barak, Phillip. January 5, 1999. "Essential Elements for Plant Growth." University of Wisconsin, Horticulture/Soil Science, Plant Nutrient Management. http://www.soils.wisc.edu/~barak/soilscience326/

Munns, Donald N. "Nutrient Deficiencies and Toxicities." Land, Air and Water Resources, University of California at Davis. http://www.hydrofarm.com/content/articles/deficiencies.html

Perry, M. S. June, 2001. General Botany Laboratory Manual, Biology 154. Allan Hancock College Graphics Department, Santa Maria, pp. 87-90.

"Diagnosing Nutritional Deficiencies." Department of Horticulture Sciences, Texas A&M University System. (Greenhouse Management Handbook). http://aggie-horticulture.tamu.edu/greenhouse/ghhdbk/diagn.html