Cobalt Deficiency
Posted: Sunday, December 19, 2010
by Robert Wright
UsaveHydroponics
Atomic Number: 27
Atomic Symbol: C0
Electron configuration: [ Ar] 4s23d7
Molecular Form of Cobalt (how plants take it up)
The distribution of Co 2+ in plants is entirely species dependent.
Cobalt , considered to be an essential element by some, is needed for nitrogen fixation. In a sense, it is essential element for nitrogen - fixing bacteria. This makes cobalt an important element for legumes and other nitrogen - fixing plants. There is some evidence that it plays some other role in nitrogen metabolism in legumes besides fixation.
Algae - The biosorption of cobalt in black sea brown algae Cystoseira barbara and seaweed Ascophyllum nodosum involves a physical absorption by ion - exchange mechanism.
Fungi - In fungi cobalt accumulates by two processes. The metabolism - independent one presumably involves cation binding to the cell surface. This process is followed by the metabolism - dependent type through progressive uptake of large amounts of cations. Accumulated Co is transported (at the rate of 40/p.g/h/100 mg dry weight of N. crassa) mainly into the intracellular spaces and vacuoles. Both uptake and transport depend on pH and temperature.
Ionic Charge
- Co + 2
- Co + 3
Cobalt Chloride (pH 4.6)
Sources:
Most of the Earth's cobalt is in its core. Cobalt is of relatively low abundance in the Earth's crust and natural waters. Cobalt occurs in the minerals cobaltite, smaltite, and erythrite, and is often associated with nickel, silver, lead, copper, and iron ores, from which it is most frequently obtained as a by - product. It is also present in meteorites. Important ore deposits are found in Zaire, Morocco, and Canada. The U.S. Geological Survey has announced that the bottom of the north central Pacific Ocean may have cobalt - rich deposits at relatively shallow depths in water close to the Hawaiian Islands and other U.S. Pacific territories.
Cobalt Functions in Plants:
Cobalt, a component of vitamin B-12, has long been regarded as an essential element for animals and microorganisms but has not been recognized as such for plants. The only physiological role as yet ascribed to this metal is in the fixation of molecular nitrogen in root nodules of leguminous plants which posses vitamin B 12 and cobamide coenzymes and the non - legumes, Alnus glutinosa and Casuarina cunninghamiana
Cobalt Deficiency in Plants:
Low concentration of Co 2 + in medium stimulates growth from simple algae to complex higher plants. Relatively higher concentrations are toxic. High concentrations of cobalt hamper RNA synthesis, and decrease the amounts of the DNA and RNA probably by modifying the activity of a large number of endo - and exonucleases.
Application Recommendations:
In New Zealand and elsewhere, cobalt deficiency is often corrected by the use of cobaltized superphosphate, limestone high in cobalt, or simply crude cobalt salts.
Author: Robert R. Wright
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