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Site author Richard Steane
The BioTopics website gives access to interactive resource material, developed to support the learning and teaching of Biology at a variety of levels.

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Vitamins and Minerals

Vitamins and Minerals are categories of micronutrients, as opposed to macronutrients (carbohydrates, fats and proteins).

They are needed in smaller quantities - usually milligrams rather than grams.

Vitamins and minerals are very different sorts of substances. Vitamins are organic (moderately complex molecules based on covalent carbon-carbon bonds) whereas minerals are inorganic (simpler - often only one or two elements - usually in the form of ions).

Vitamins

Most vitamins are produced by plants and micro-organisms, but they may be concentrated in some animal tissues
A vitamin is a substance that is needed by the body, and which cannot be synthesised in necessary amounts, so it must be provided in the diet. It is therefore defined in the context of certain animal groups. The same substances may be produced in adequate amounts in other animal groups, or in plants, but they are not termed vitamins in this context. Vitamins perform a variety of functions in the body, mostly to do with transfer of energy. They can act as enzyme cofactors, as prosthetic groups attached to enzymes or as coenzymes, moving chemical groups or electrons from compound to compound within the cell.

The term vitamin was coined by Casimir Funk, from vital + amine. He was studying thiamine - lack of which causes beri-beri - but other vitamins were found not to have an amine (NH2) group, so the term was shortened.

Initially the chemical composition of vitamins were unknown until large enough amounts were prepared for analysis and identification methods were developed, so the system of describing them by letters was started. Then some, initially given the same letter, were found to be different, so groups like the B group were subdivided with numbers (B1, B2 etc.). Some were found to duplicate others, or not considered true vitamins, so there are gaps ; there is no vitamin B4, F , G, etc.

Some vitamins exist in several forms called vitamers. These are often variations on the same molecular theme, but sometimes they differ in activity compared with the basic version, and perhaps do not perform all the functions of the main vitamin.

Certain vitamins (B group, C) are water-soluble. This means they pass through the body in the blood system and are continuously excreted in urine. Consequently they need to be regularly obtained from the diet.

Others (A,D,E,K) are fat-soluble. These tend to be stored in the liver, and are not so quickly used up. This explains why liver is an important source of these vitamins.

It must be stated that most people consume adequate quantities of most vitamins if they have a balanced diet. In fact researchers originally had problems removing them from the main categories of food (carbohydrates, fats and proteins).

However people on restricted diets or with fairly serious metabolic problems may suffer from vitamin deficiency. Vitamin deficiency can be primary - poor vitamin sources in one's daily diet - or secondary, which may be a result of conditions that affect absorption in the intestine, the body not being able to use the vitamin, or an increase in the excretion of the vitamin from the body.

Some vitamins have been recommended at higher than usual amounts for treating metabolic disorders, and in cases where there may be interactions with drugs used to treat other conditions. Some health care and beauty products containing vitamins and associated compounds have been claimed to have a variety of advantages.

In the grid below there are several links to interactive 3-D molecular models on this site which have been converted into a fairly user-friendly format (Jsmol).

DISCLAIMER: This material is provided in good faith, and for educational purposes. Do not rely on it in any way for medical purposes or as justification for outlandish dietary modification.
However, I would be grateful to be informed of any major errors or omissions.
Vitamin
+ link to 3-D model
Role in body
Deficiency causes
Good sources
Amount required
mg/day
[RDA]
Vitamin
+ link to 3-D model

A
Retinol

(+ others)
Role in body
Converted into retinal which detects light in rod and cone cells of the retina (at the back of the eye)
Deficiency causes
Night blindness
Good sources
Liver, many vegetables
Amount required
mg/day
[RDA]

0.6-0.7
Vitamin
+ link to 3-D model

B1
Thiamine




Role in body
Deficiency causes
Beri-beri
symptoms include severe lethargy & fatigue, + complications affecting cardiovascular, nervous, muscular, and gastrointestinal systems
Amount required
mg/day
[RDA]

1.4


Good sources
Yeast, cereal grains e.g. rice [but removed when processed into white rice], beans, nuts, and meat, esp. pork
Vitamin + link to 3-D model
B2
Riboflavin


Role in body
Precursor to FAD and FMN (involved in a number of biochemical transformations to do with energy, as well as other B group vitamins).
Also acts as an antioxidant
Deficiency causes
Inflammation of the lips, lining of mouth and tongue, mouth ulcers, cracks at the corners of the mouth, and a sore throat or more general dry and scaling skin, fluid in the mucous membranes. Eyes may also be itchy/watery/bloodshot, and sensitive to bright light.
Amount required
mg/day
[RDA]

0.3-1.3




Good sources
Milk and dairy products, Lean meats, Eggs, Green leafy vegetables, Legumes, Nuts, Yeast
Flours and cereals are often fortified with riboflavin.

Riboflavin is destroyed as a result of exposure to light.
Vitamin + link to 3-D model
B3
Niacin, nicotinamide (niacinamide)










Role in body
Precursor to NAD and NADP - hydrogen and electron acceptors in respiration and photosynthesis.
Niacin is involved in the production of various steroid hormones in the adrenal glands. It is also thought to help improve (blood) circulation and reduce atherosclerosis.

It has been found that in higher doses, niacin (but not nicotinamide) blocks the breakdown of fats and increases the level of high-density lipoprotein (HDL) or "good" cholesterol and lowers low-density lipoprotein (LDL) in blood.
Deficiency causes
Pellagra
cracked, scaly skin, dementia, and diarrhea
Amount required
mg/day
[RDA]

14-18
Good sources
Yeast and yeast products, most meats, many fruits and vegetables

Maize : (sweet)corn may prove to be deficient in niacin unless cooked in alkaline solution

In the liver, niacin can also be synthesized from tryptophan, an essential amino acid. This conversion requires riboflavin (vitamin B2), pyridoxine (vitamin B6) and iron.
Vitamin + link to 3-D model
B5
Pantothenic acid




Role in body
Precursor to Coenzyme A which transfers smaller molecules in the process of respiration and in other processes

Many other possible functions have been suggested.

Deficiency causes
Symptoms very rare but perhaps seen in extreme malnourishment (victims of famine and maltreated prisoners of war):
extreme tiredness due to reduced energy metabolism, neurological conditions e.g numbness due to reduced acetylcholine synthesis, perhaps increased sensitivity to insulin because receptors are not deactivated by acylation.
Amount required
mg/day
[RDA]

6



Good sources
Pantothenic means everywhere, and this is found in nearly every food, especially whole-grain cereals, vegetables (legumes), fruit, eggs and meat
Vitamin
+ link to 3-D model

B6
Pyridoxine, pyridoxal, pyridoxamine,
Role in body
Precursor to pyridoxal 5'-phosphate (PLP), which acts as coenzyme in the synthesis of amino acids and neurotransmitters, and other reactions
Deficiency causes
Muscle weakness, nervous problems (irritability, depression, difficulty concentrating, and short-term memory loss)
Amount required
mg/day
[RDA]

5-25




Good sources
Meat, fish, dairy products, vegetables, cereals - especially wheat germ and whole-grain flour, and nuts.
Vitamin
+ link to 3-D model

B7
Biotin

(also sometimes known as vitamin H)
Role in body
Essential cofactor of enzymes involved in carboxylation reactions, e.g. pyruvate carboxylase and acetyl-CoA carboxylase, which catalyze key reactions in gluconeogenesis, fatty acid metabolism, and amino acid catabolism.
Deficiency causes
Main cause of deficiency: Raw egg white contains a protein avidin which absorbs biotin, making it unavailable. Cooking deactivates it, and does not damage biotin.
In various food sources, biotin is bound to a protein which must be broken down before it can be absorbed.

Symptoms of biotin deficiency: Hair loss , conjunctivitis, facial and other rash, various neurological symptoms.
Amount required
mg/day
[RDA]

(uncertain)



Good sources
Liver, green leafy vegetables, egg yolk.

Intestinal bacteria produce enough biotin for most people.
Vitamin + link to 3-D model
B9
Folic acid







Role in body
Deficiency causes
Macrocytic or megaloblastic anemia

Neural tube defects in developing embryos

plus other possible disorders, including cancer.
Amount required
mg/day
[RDA]

0.2
(double this in pregnancy)




Good sources
Many leafy vegetables: broccoli, brussels sprouts, spinach, and also legumes: peas, beans, lentils, chickpeas. In many countries different cereal products e.g. bread, flour, pasta and breakfast cereals are fortified with it. It is also available from animal sources: liver, kidney, egg yolk, and yeast and associated products.
Vitamin + link to 3-D model
B12
(Cyano)
cobalamin




Role in body
Necessary for the formation of healthy red blood cells - in conjunction with vitamin B9 (and iron)

also involved on fatty acid synthesis and energy metabolism
Deficiency causes
Brain and nervous system damage: fatigue, depression, and poor memory.

Megaloblastic anemia

Vitamin B12 deficiency can be caused by the metabolic disorder pernicious anemia, which is an autoimmune disease which attacks certain cells of the stomach so that gastric intrinsic factor is not produced. This is necessary for the absorption of vitamin B12 in the small intestine; in its absence B12 in not absorbed from food that has been eaten.
Amount required
mg/day
[RDA]

0.002 - 0.003
(2-3g )
Good sources
Meat, especially liver, eggs, milk products, shellfish
Not produced in plant sources
Vitamin + link to 3-D model
C
ascorbic acid




Role in body
Needed for the formation of collagen in connective tissue and for healthy teeth, gums and blood vessels;
also as an antioxidant
Deficiency causes
Scurvy
Gingivitis (inflammation of the gums) and bleeding gums; rough, dry, scaly skin; decreased wound-healing rate, easy bruising; nosebleeds; decreased ability to ward off infection
Amount required
mg/day
[RDA]

40-90




Good sources
Fruit and vegetables:
citrus, capsicums (peppers), strawberries, blackcurrants,
potatoes (esp skins), broccoli, brussels sprouts
Role in body
Converted into calcitriol which circulates in the blood and functions as a hormone which increases the uptake of calcium (Ca2+) from the gut into the blood
Deficiency causes
Rickets (in children), osteomalacia (in adults) - bone deformities such as bowed legs caused by softening of the bone, possibly leading to curvature of the spine and thickening of the ankles, wrists and knees
- may also be caused by lack of the mineral calcium in the diet.
Amount required
mg/day
[RDA]

0.005 - 0.015
(5-15g)

[Some sources suggest wider range - possibly due to lifestyle differences]



Good sources
Liver, fish, cod liver oil
Vitamin D is also produced in the skin by the action of ultraviolet light on various lipid molecules such as cholesterol. The intensity of ultraviolet light varies in different areas of the world, and this production is also affected by skin colour and amount of skin covered by clothing.
As such it may be an issue with dark skinned people in certain latitudes, or those who do not go outside in the sun or expose themelves to it.
Vitamin + link to 3-D model
E
Tocopherol
and others






Role in body
Antioxidant: it acts as a peroxyl radical scavenger, in conjunction with vitamin C, and prevents the oxidation of polyunsaturated fatty acids

It also acts as an enzymatic activity regulator in smooth muscle growth and has an effect on gene expression, specifically those responsible for the repair of wounds and regeneration of the tissue damaged during atherosclerosis.
Deficiency causes
Neuromuscular problems due to poor nerve conduction

possibly heart disease and atherosclerosis

Vitamin E deficiency is quite rare, and more likely to be caused by problems in the absorption of fat than by inadequate diet.
Good sources
Plant oils e.g. wheat germ, sunflower
Amount required
mg/day
[RDA]

3-4
Vitamin + link to 3-D model
K
Phylloquinone




Role in body
Cofactor in the formation of coagulation factors II (prothrombin), VII, IX, and X by the liver.

Also required for bone protein formation and calcification.
Deficiency causes
Problems with blood clotting and loss: anaemia, bruising, bleeding from the nose or gums, and heavy menstrual bleeding in women. Greater chance of "all-cause mortality", coronary heart disease, arterial calcification and osteoporosis.
Amount required
mg/day
[RDA]

0.075
(75g)




Good sources
Green leafy vegetables: broccoli and spinach
vegetable oils, cereals
meat and dairy foods (small amounts) - higher amounts in yoghurt and cheese

Minerals

Minerals are fairly unreactive (chemically), which is surprising to some people. For example, calcium and phosphorus are thought of as reactive - even dangerous - in the context of these substances as elements. However as compounds these reactive properties are replaced - neutralised - so that calcium ions and phosphate ions are very different from the elements. Another good example would be sodium chloride, a compound of sodium and chlorine. This is in fact commonly known as table salt. In fact many minerals are known as mineral salts, or just as salts.

This transformation is explained by the fact that minerals are generally ions - atoms or groups of atoms of elements that have gained or lost electrons from their outer shell, which takes away the most obvious characteristics of the elements seen on their own, and gives these ions a charge. In terms of biological activity, most of the variation between ions of minerals/elements is explained by differences in charge and the size of the atomic nuclei involved.

There are two basic categories of ions, depending on the type or sign of charge they possess: positively charged ones are also called cations and negatively charged ones are called anions. Generally metals have positive ions, and non-metals have negative ions.

In normal circumstances (in living organisms), ions do not exist on their own. Each positively charged ion must be accompanied by a negatively charged ion, and some ions carry more than one charge so the number of positive and negative charges must balance each other. So in sodium chloride (NaCl) there are equal numbers of sodium ions Na+ and chloride ions Cl-, whereas in calcium chloride (CaCl2) there are twice as many Cl- ions as Ca2+ ions. This means that when we are talking about sodium ions Na+ or potassium ions K+ there must be an accompanying number or assortment of anions - possibly chloride ions Cl- or sulphate ions SO4- but in solution they are not partnered up in the way that sodium chloride and potassium sulphate might be in a jar in a chemistry lab or a drugstore.

This situation is slighty shifted when the pH of a solution is altered: increasing the pH from 7 to 8 (making it more alkaline) reduces the concentration of H+ ions to 1/10 of the previous value, whilst decreasing the pH from 7 to 6 (making it more acidic) raises the concentration of H+ ions to 10 x the previous value. Changing the pH of a solution can alter the solubility of other ions.

Minerals can be thought of as originating from the earth's crust (and the sea's water) in the form of salts which when purified are often seen as (usually white or colourless) crystals. But when absorbed into the body they are usually in the form of ions, dissolved in water. Some elements can interact with organic compounds and become absorbed in fatty tissue.

Different minerals perform different functions in animals and plants, a reflection of the different biochemical processes which are characteristics of each. There is some overlap with basic biological processes.

Minerals from a human/animal perpective

Some minerals are incorporated into major parts of the body such as the skeleton and teeth, and some form important parts of cells. Others are essential components of the blood and body fluids. The amount of each mineral required may vary according to age and lifestyle.

Certain minerals also participate in some of the same metabolic processes that vitamins are known for, so the distinction here is not so clear.

There is a subcategory of minerals that are needed in very small quantities: these are called trace elements.

Mineral
(element)

Role in body
Deficiency causes
Good sources
Amount required
mg/day
[RDA]
Mineral
Calcium
(Ca2+ ions)









Role in body
A (solid) component of bones and teeth (enamel)
- in conjunction with phosphate and other ions
[Bones also have an organic matrix - mainly collagen]
Ca2+ ions are
  • participants in nerve-muscle interaction and muscular contraction
  • required for blood clotting
  • involved in many enzyme reactions
Deficiency causes
Osteoporosis - weakening of the bones (more common in women after the menopause)

Rickets (developing bone malformation in children) and osteomalacia (loss of skeletal calcium in adults) may be due to calcium deficiency, vitamin D (Calciferol) deficiency, or both.

Calcium may be withdrawn from bones and teeth ('resorption') to provide calcium ions for other body functions (including baby's bone formation in pregnancy)
Amount required
mg/day
[RDA]

750-800 (adults)
1000 (adolescents)
300-700 (0-9yrs)
Good sources
Milk, cheese and other dairy products, eggs, canned fish with bones (salmon, sardines),
green leafy vegetables, nuts, seeds, tofu
Finely ground chalk (creta preparata) may be added to white bread flour.
Carnivorous animals obtain calcium from bones consumed.

Note: calcium uptake is mediated by vitamin D (calciferol) - which may be limiting under certain conditions (reduced exposure to sunlight)
Mineral
Phosphorus
(as phosphate ions PO43-)
but HPO42- and H2PO4- are more common in pH 5-9
Role in body
(Solid) component of bones and teeth (mostly as calcium hydroxyapatite)
Component of nucleic acids (DNA, RNA, nucleotides, ATP etc)
All cell membranes are phospholipids
Phosphate groups are involved in activation of carbohydrates in respiration and photosynthesis,
and also in control of enzymic processes and gene expression (phosphorylation)
Deficiency causes
Rickets, osteomalacia, osteoporosis
See above
Amount required
mg/day
[RDA]

700




Good sources
'Protein foods': milk and milk products, meat and pulses, such as beans, and lentils, nuts, and whole grains. Smaller amounts in vegetables and fruit.
Mineral
Iron
[iron(II) ions - 'ferrous ions' - (Fe2+)
& iron (III) ions- 'ferric ions' - (Fe3+)]
Role in body
Part of the haemoglobin molecule in red blood cells, myoglobin in muscle cells, cytochromes and catalase in all body cells
Deficiency causes
Anaemia, pale complexion, fatigue, low energy levels, rapid heartbeat, shortness of breath

May be compounded by menstrual blood loss in females
Amount required
mg/day
[RDA]

18 (women)
8 (men)


Good sources
Meat, seafood, liver, green vegetables, pulses

Breakfast cereals may contain finely divided iron particles
Mineral
Iodine
(iodide ions I-)



Role in body
Part of molecules of thyroid hormones triiodothyronine T3 (more active) and tetraiodothyronine T4 - thyroxine
These hormones control the basal metabolic rate of body cells.
Deficiency causes
Goitre - enlargement of thyroid gland in neck
to maximise conversion of dietary iodide to thyroglobulin (precursor to T3 and T4).

This condition is most common in areas furthest from the sea, and so least likely to consume seafood.
Amount required
mg/day
[RDA]

150 µg


Good sources
Seafood, seaweed
(seawater contains 60 ppb of iodide, so these organisms absorb and concentrate it).

Iodide may be added to salt ('iodised salt')

Radioactive iodine I-131

Iodine-131 is an isotope of Iodine, a major fission product of uranium and plutonium, produced in nuclear power plants and atomic bombs.
It is a beta-emitter with a half-life of 8 days, and may cause cancer, especially of the thyroid gland in which it concentrates after absorption.
If released into the environment, it represents a significant health hazard. This was seen in atomic bomb tests in the 1950's, as well as after the Chernobyl nuclear power plant disaster in 1986 and in the Fukushima Daiichi nuclear crisis after an earthquake in 2011.

Control measures

In the event of a nuclear disaster, authorities may distribute uncontaminated, normal iodine (I-127) in the form of potassium iodide tablets. These contain enough iodine to saturate the body's reserves (130mg per day), so radioactive iodine is not stored (in the thyroid) and is more likely to be excreted in urine.

Use in medical context

Iodine-131 may also be used to control thyroid cancer. It kills cancerous tissue here effectively without spreading significantly to other parts of the body.
Mineral
Potassium
(K+ ions)





Role in body
In blood and all body fluids, to establish an osmotic balance, (together with sodium and chloride ions). This may be called water-electrolyte balance.
Actively transported into cells, especially nerve cells.
Important in nerve and muscle cell activity.
Deficiency causes
Hypokalemia (blood serum levels below 3.5 mmol/L)
Symptoms may include tiredness, cramps, weakness, constipation and abnormal heart rhythm.
Good sources
A variety of fruit, meat and vegetables
Amount required
mg/day
[RDA]

3,500-4,700
(highest of all minerals)
needed to balance loss in urine
Mineral
Sodium
(Na+ ions)





Role in body
In blood and all body fluids, to establish an osmotic balance, (together with potassium and chloride ions) - water-electrolyte balance.
Actively transported out of cells, especially nerve cells. The main partner in co-transport of other ions across membranes.
Important in nerve and muscle cell activity.
Deficiency causes
Hyponatremia (blood serum sodium concentration below 135 mmol/L) - may result from excessive sweating in high-endurance sport activities!
Amount required
mg/day
[RDA]

2400 - equivalent to 6g of salt (sodium chloride)




Good sources
Most foods contain some sodium, but added salt is a recurring point of contention.
Many processed foods contain excessively high levels of salt as a flavour enhancer and presevative.
Excess consumption can result in high blood pressure, which may cause strokes and heart attacks.
Mineral
Chloride
(Cl- ions)







Role in body
In blood and all body fluids, to establish an osmotic balance, (together with potassium and sodium ions) - water-electrolyte balance.

Chloride ions (along with hydrogen ions) are secreted by parietal (oxyntic) cells in the gastric glands of the stomach and this hydrochloric acid lowers the pH of the stomach contents, making proteins more accessible to the enzyme pepsin.
Deficiency causes
No specific effect
Amount required
mg/day
[RDA]

3400 - equivalent to 5g of salt (sodium chloride)






Good sources
Most foods contain some chloride in conjunction with sodium, but added salt is a recurring point of contention.
Mineral
Magnesium
(Mg2+ ions)



Role in body
Required in many enzyme-controlled reactions, especially in conjuction with ATP (and DNA and RNA)
Deficiency causes
Often no symptoms but may include the following:
Hyperexcitability, muscular symptoms (cramps, weakness), fatigue, loss of appetite, apathy, confusion, insomnia, irritability, poor memory, and reduced ability to learn
Most people do not include enough in their diet, and other lifestyle factors may reduce the availability of magnesium.
Amount required
mg/day
[RDA]




270-300
Good sources
Leafy green vegetables (chlorophyll contains magnesium), pulses e.g. soybeans, nuts, and fruit
Mineral
Molybdenum
(Mo2+ ions)?


Role in body
Part of several oxidase enzymes:
xanthine oxidase
aldehyde oxidase
sulfite oxidase
Deficiency causes
Molybdenum deficiency!
Amount required
mg/day
[RDA]

0.045
[trace element!]


Good sources
Legumes, whole grains, nuts

Other elements, (possibly) required in smaller amounts

Sulphur
Zinc
Chromium
Manganese
Copper
Selenium
Boron
Silcon
Arsenic
(Cobalt)
part of (cyano)cobalamin (vitamin B12)

Minerals and Green Plants

Green plants absorb mineral ions from the soil and incorporate them into their cells. The unique process of photosynthesis which relies on the green pigment chlorophyll produces carbohydrates which can then be converted into other classes of organic compound, notably proteins and nucleic acids.

Consequently different mineral ions are needed by plants, and since there is a limited amount of these available in the soil they may act as limiting factors in plant growth. Put another way, several inorganic mineral salts usually improve plant growth.

Unlike animal cells, plant cells are surrounded by a very dilute solution of mineral nutrients. This results in water entering the plant cells by osmosis, causing them to be turgid as the hydrostatic pressure acts against the plant cellulose cell walls.

Also unlike animals, plants do not permanently dispose of mineral ions. They do not have a daily requirement (for replacement). Obviously different mineral ions are required in different amounts, and this will also depend on the plant's phase of growth. The absolute amount of mineral nutrition in the soil is difficult to gauge, and extra mineral nutrients are added optimistically. An excess of minerals could conceivably have an osmotic effect.

For this reason and for comparison I have looked up the amounts - expressed as parts per million (ppm) - of the various minerals considered optimal for use in hydroponic growth systems - which obviously do not involve soil.

Mineral
Role in plant cells
Deficiency causes
Good sources
Amount required
[in hydroponic systems]
ppm
Mineral
N: Nitrogen
as nitrate ions NO3-

Other N-containing material may be broken down by microbial action to provide this
Role in plant cells
Used to produce amino acids for protein production, and for nucleic acids DNA, RNA

Hence promotes vegetative growth and development of flowers, fruits and seeds
Deficiency causes
Poor growth, leaves not so green (more yellowy green) - 'chlorosis'
Amount required
ppm

125-224






Good sources
'Chemical' sources:
calcium nitrate, potassium nitrate, ammonium nitrate - also provide Ca2+, K+, NH4+
'Organic' sources;
urea CO(NH2)2
Less defined:
'blood, fish and bone'
animal droppings etc
Mineral
P: Phosphorus
as phosphate ions:
PO43-
HPO42-
H2PO4-
Role in plant cells
Component of nucleic acids (DNA, RNA, nucleotides, ATP etc) Involved in activation of carbohydrates in respiration and photosynthesis, and also in control of enzymic processes and gene expression (phosphorylation and photophosphorylation)

Hence promotes growth of roots and shoots
Deficiency causes
General stunting of growth

Leaves may be smaller and darker than usual
Amount required
ppm

39-45
Good sources
inorganic phosphate fertiliser

bonemeal
Mineral
K: Potassium ions K+





Role in plant cells
Involved in the opening and closing of stomata (by regulating the osmotic potential within guard cells), hence controls intake of CO2 for photosynthesis and the transpiration stream which provides water and other inorganic ions for plants.
It is said to activate a number of enzymes involved in photosynthesis and respiration.
Deficiency causes
Leaf tips become brown and curl; leaf blades become yellow between veins.
Symptoms are more marked in older leaves.
Plant growth and development of roots, seeds and fruits is reduced.
Amount required
ppm

280-350




Good sources
Inorganic potassium salts: potassium chloride (chloride no use to plants), potassium nitrate (nitrate also provides nitrogen)

Pot ash (residue from burnt wood)
Mineral
Mg:
Magnesium ions
Mg2+







Forms (the central) part of the chlorophyll molecule

Magnesium ions are co-factors for the action of enzymes required for important stages in photosynthesis (specifically carbon fixation): Ribulose Bisphosphate Carboxylase (RUBISCO) and Phosphoenolpyruvate Carboxylase (PEPC).
Deficiency causes
Marked chlorosis (yellowing) between leaf veins, which stay green
Good sources
'Epsom salts' (magnesium sulphate)
Amount required
ppm

48-65
Mineral
Fe: Iron
Fe2+, Fe3+ ions
Role in plant cells
Needed for enzymes involved in chlorophyll production
Deficiency causes
Chlorosis
Noticeable in alkaline soils which reduce solubility of iron compounds
Good sources
Red soils contain iron compounds
Amount required
ppm

2

Other elements, (possibly) required in smaller amounts

(< 1ppm)

Manganese (Mn)
Zinc (Zn)
Boron (B)
Copper (Cu)
Molybdenum (Mo)


Other related topics on this site

This topic has connections with other topics on this website:

Inorganic ions

Web links

Vitamin From Wikipedia, the free encyclopedia

Vitamins and minerals from NHS Choices

Vitamin and mineral requirements in human nutrition Second edition Authors: World Health Organization, Food and Agricultural Organization of the United Nations

A Recipe for Hydroponic Success Providing all of the essential elements in the right quantity and the right proportion to each other can seem like a daunting task to even the most mathematically gifted growers. by NEIL S. MATTSON & CARI PETERS

Other vitamins and minerals

List of micronutrients


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