This group includes elements that are used as nutrients by only a limited number of plant species.  When high concentrations of an element, not commonly found in most plants, is seen in a particular species, it raises the possibility that the element is essential for that species.  The plants may use these for non-nutritional purposes.  It is thought that species where these elements are present may use them for protection against invading bacterii.  For example, Barium is found in brazil nuts; Aluminum in tea; Chromium, Nickel and Cobalt in gramineae; Silicon in rice and cucumbers.


BROMINE  (Br ) 79.90 Atomic Weight

(Essential Trace Element?)

Bromine is a rare element dispersed throughout the earth’s crust in compound form.  In sea water, it constitutes 65 parts per million by weight.  It combines readily with many elements. With the exception of a few plant species, Bromine has no known biological role.  It is a toxin that is sometimes used in the control of nematodes and other invading microbes in the soil.  Its main uses are in the medical and fossil fuel industries.  It is not known why certain plant species contain significant levels of  Bromine.