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Nutrients
Below are listed all the essential elements for health plant life in order of increasing quantity.
Mo Molybdenum |
part of nitrate reductase; essential for N fixation |
Chlorosis or twisting of leaves, whiptail disease in acidic soils. | Excess Mo causes Fe and Cu deficiencies. |
Cu Copper |
component of plastocyanin, aplastid pigment; present in lignin of xylem elements; activates enzymes |
Young leaves dark green, twisted, and wilted; tips of roots and shoots remain alive; xylem loses rigidity; rarely deficient | Excess Cu results in Fe deficiency, especially in acid soils. |
Zn Zinc |
ecessary for formation of pollen; involved in auxin synthesis; maintenance of ribosome structure; activates enzymes |
Causes most problems in all micronutrients. Chlorosis, smaller leaves, thin; reduced internodes; distorted leaf margins; older leaves most affected. New leaves grow contorted and twisted, dropping early. | Excess Zn causes dark mottled leaves |
Mn Manganese |
photosynthetic O2 evolution; enzyme activator; electron transfers |
Interveinal chlorosis; appears first on older leaves from base; necrosis common; disorganisation of lamellar membranes; immobile when pH over 7.5 and often accompanies Fe deficiency | Excess Mn arises in acidic media giving orange-brown mottling |
B Boron |
ssential for growth of pollen tubes; regulation of enzyme function; possible role in sugar transport |
Death of apical meristem; leaves
twisted and pale at base; swollen, discoloured root tips; young
tissue most affected with grey specks, shoots turn grey | Excess B causes discolouration and death of leaf tips, then margins. |
Fe Iron |
equired for synthesis of chlorophyll; component of cytochromes and ferredoxin; cofactor of peroxidase and some other enzymes |
Interveinal chlorosis; short and slender stems; buds remain alive; affects young leaves first, yellows from base, eventually necrosis; immobile when pH over 7.5 or high Cu levels | Excess Fe causes leaf bronzing. |
Cl Chlorine |
activates photosynthetic elements; functions in water balance |
Wilted leaves; chlorosis or bronzing; necrosis; stunted, thickened roots | Ecess Cl also causes bronzing. |
Macronutrients | Function | Deficiency | Toxicity |
S Sulphur |
part of coenzyme A and the amino acids and cystine and methionine; can be absorbed through stomata as gaseous SO2 |
Interveinal chlorosis; usually no necrosis; affects young leaves, lime green to yellow; stem elongation; rarely deficient; immobile when high pH or Ca levels | SO2 causes interveinal chlorosis. |
P Phosphorus |
part of nucleic acids, sugar phosphates, and ATP; component of phospholipids of membranes; coenzymes |
Stunted growth, dark blue/green to purple pigmentation; accumulation of anthocyanin pigments, delayed maturity; leaves contort and drop, often with dark blotches, lower leaf tips may turn brown and curl down; reddening on underside of stem; affects entire plant; low pH makes P unavailable as does cold, wet heavy soils; excess Fe and Zn in soil binds with phosphates; second to N, P is element most likely to be deficient | Excess P reduces availability of Zn, Fe, Mg, and calcium in young leaves. Watch especially symptoms for Zn |
Mg Magnesium |
part of chlorophyll; enzyme activator; protein synthesis |
Interveinal chlorosis and reddening of leaves; red spots; leaf lips turn upward; older leaves most affected, and drop early; made unavailable by high K levels and low pH | Excess Mg creates small, dark green leaves with curled edges. |
Ca Calcium |
membrane integrity; in middle lamella; functions as “second messenger”to co-ordinate plant's responses to many environmental stimuli; reversibly binds with calmodulin, which activates many enzymes |
Required in large quantities. Death of root and shoot tips; very dark
green foliage and slow growth; young leaves and shoots most affected, distorted and withered | Excess Ca causes wilting and Mg, K, Fe and Mn deficiencies. |
K Potassium |
regulates osmotic pressure of guard cells, thereby controlling opening and closing of stomata; activates more than 60 enzymes; necessary for starch formation |
Chlorosis and necrosis, weak stems and
roots; roots more susceptible to disease; young leaves develop mottling, older leaves most
affected, first tips and margins; leaf tip curls (often downwards)
and brown spots and tips develop; common in tomatoes, potatoes, beans and
fruit. Recovery is slow. | Excess K gives scorching of plants and wilting, may lead to Ca or Mg deficiency. |
N Nitrogen |
part of nucleic acids, chlorophyll, amino acids, protein, nucleotides, and co-enzymes |
N is very mobile and
dissipates quickly - element most likely to be deficient. General chlorosis, stunted growth;
older leaves yellow first, stem(underside) and leaf veins might
develop red/purplish colouration due to accumulation of anthocyanin
pigments; small, brightly coloured fruit; |
Toxicity shows as excessive lush, green foliage, stems weak, leaves go copper/brown and drop |
O Oxygen |
major component of plant's organic compounds |
Rarely limiting enough to cause specific symptoms | Photorespiration |
C Carbon |
major component of plant's organic compounds |
Rarely limiting enough to cause specific symptoms | |
H Hydrogen |
major component of plant's organic compounds |
Rarely limiting enough to cause specific symptoms |