ELEMENTS IN PLANTS |
Thus those heavy metals which occur in metallophytes but which are toxic at all concentrations are not included in this list, because the plant will invariably grow better without them! But there are just a small few heavy metals which do confer some mineral benefit to plants, although they are toxic at higher concentrations - and these are included, chromium being one such element. [For a list of detrimental heavy metals occurring in metallophytes, see Thrift. But there may be a little bit of overlap between some essential elements and metallophytic elements]. Any radioactive elements in the soil are likely to increase the rate of variation and of evolution; they are likely responsible for at least some part of variation and speciation over the aeons which some of the radioactive isotopes have been in the soil (some radioactive isotopes have very long lifetimes; others with much shorter halflives are replenished by the radioactive decay of those radioactive isotopes with much longer halflives). [For info on radioactive isotopes (and much more) readers are directed to one of your Authors' other websites: Info for Isotopes]. |
MANGANESEBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about Manganese
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MAGNESIUMBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about Magnesium
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CALCIUMBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about Calcium
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PHOSPHORUSBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about phosphorus
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POTASSIUMBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about potassium
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NITROGENBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about nitrogen
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SILICONBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about Silicon
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VANADIUMVanadium readily forms large complexes which invariably possess catalytic and enzymatic properties in many organisms from plants to fungi, lichens and cyanobacteria. Vanadium is responsible for incorporating atoms of either bromine or chlorine into many marine species, forming organochlorides and organobromides, and is actually responsible for the production of most naturally occurring organobromine compounds to be found (mostly in species living in the Worlds oceans). Vanadium complexes are also involved in some nitrogen-fixing micro-organisms, especially in the Azotobacter family of micro-organisms (such as those within Water Fern (Azolla filiculoides, an unusual nitrogen-fixating plant). In the role of Nitrogen Fixation vanadium replaces the more commonly utilised molybdenum or iron nitrogenases.
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BORONBoron is required by plants for both growth and reproduction. Boron (in the form of chemical compounds) in the soil is found in organic matter. In hot, dry weather the decomposition rate of organic matter slows down reducing the quantities of boron released into the soil which affects the growth rate of many crops such as Brussel Sprouts, Radishes, etc. Also dry soil conditions restrict plant root activity and can be the cause of temporary boron deficiency, causing poorer plant yields.Plants are able to uptake boron best when the pH of the soil is between 5.0pH and 7.0pH. At higher pH values (more alkaline) boron uptake is reduced and crops suffer. Liming soils will reduce the alkalinity and encourage better use of boron by the plants. Coarse sandy soils contain a lot of quartz and are typically low in minerals which contain boron. Boron is also soluble in water and in areas of high rainfall the leaching of boron compounds out of the soil is of concern, especially on sandy soils.
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CHLORINEApparently Chlorine is an essential micronutrient for many plants - moreover the growth rate of many plants is significantly reduced by the absence of chloride (Cl-) ions. Cl- is involved in both the turgor-regulation and osmo-regulation. It regulates the activity of enzymes and is also implicated in the regulation of pH gradients across membranes and electrical excitability.It might be supposed that Chlorine only occurs in the soil near the sea, but this would be wrong; it also occurs, at much reduced concentrations, anywhere inland. The 36Cl radioactive isotope of chlorine occurs and is generated in the upper atmosphere (stratosphere) by cosmic ray bombardment of the inert gas Argon in the form of one of the three stable isotopes of Argon, 40Ar. Argon is present in the atmosphere at the surprising concentration of 0.93% (far exceeding the present amount of CO2 in the atmosphere of just 410ppm (2018 figures). So Chlorine is generated in the skies over the ocean and over continents, where it can descend to the land and oceans. 36Cl is also generated in nuclear explosions but since atmospheric tests of these weapons has only extant between the 1954 and 1960 the chlorine from nuclear explosions in the atmosphere slowly decreased. The deposition of 36Cl from nuclear sources decreased from a peak of 4000 atoms per square metre every second to just 10 atoms/m2/s - its pre-atomic bomb testing levels - which are generated by Argon-40 bombardment in the stratosphere. It is present in the soils mainly as the chloride ion, but some organic chlorine is to be found in some fungi and soil bacteria, of which only a small fraction have ever been identified (most wont grow in laboratory culture dishes so cannot be studied). Most chlorine in plants occurs as the chloride ion, but some occurs as covalently-bonded organic compounds of chlorine (its the same for the soils too, most occurs as Cl- but some as organic chlorine.
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COBALTBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about cobalt
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CHROMIUMBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about chromium
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COPPERCopper is a micronutrient in plants; they contain 2,500 times less copper than of nitrogen. In plants tissues the amount of copper is between 3 to 10ppm. [The ideal quantities of iron in plants is some 20 times higher than for copper]. Copper is an essential element which plants need to complete their life cycle: to produce viable seed. Deficiency in copper results in chlorosis of the leaves (turning pale-green to yellow when they should not. Too much potassium, phosphorus or other micronutrients in the soil and also cause copper deficiency resulting in wrinkling and reduced size of the leaves). However, high levels of copper in the soil will compete with the uptaking up of enough iron (and sometimes molybdenum or zinc).Copper activates several enzymes in plants involved in lignin production. It also has a role in photosynthesis as well as in respiration and assisting in the metabolism of carbohydrates and proteins in plants. Copper also affects the colour of some flowers. Many copper-proteins in plants have a functional counterpart which uses iron instead as the cofactor. Soil with a high copper content results in a decreased concentration of iron by plant roots and leaves. Whereas elevated levels of Nitrogenous compounds in the soil will aggravate any copper deficiency. But high levels of Phosphorus, Zinc, Iron or Aluminium may restrict the uptake of Copper by plant roots. Copper is also an essential element for humans, who require 0.2mg per day and up to 1.3mg per day for infants and females under lactation.
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IRONIron (not in its elemental form, which quickly oxidises to rust) is an essential mineral for plants and it is most available for the uptake by plants when the soil pH is less than 6.0 (it drops rapidly as soil pH 7.0 is approached). Soils low in organic matter are more likely to be Iron deficient, which can also be caused by a high lime content, cold weather, a lot of rain or excessive levels of potassium in the soil can trigger an iron deficiency. But a balance between Iron, Copper, Manganese and Molybdenum is particularly important.
Iron deficiency in plants can be confused with manganese deficiency. Iron is vital to plants. Various sources say that it is essential for the synthesis of chlorophyll in plants, but your Author has looked at all the intermediate products used in the synthesis of chlorophyll by plants, and not one has an iron molecule in it... Another source says that the iron has an involvement in producing ALA ( It is true that Haemoglobin in the blood of humans does indeed have an iron atom at its centre (instead of a magnesium atom for several of the above plant precursors of Chlorophyll a (as well as in Chlorophyll a itself).
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MOLYBDENUMBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about molybdenum
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NICKELBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about nickel
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SULFURBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about Sulfur
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SELENIUMBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about Selenium
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VANADIUMBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about vanadium
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ZINCBlurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb Blurb about zinc
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ELEMENTS IN PLANTS |