Hydroponic culture
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APPLICATION    Hydroponic  culture, where plants are grown in mineral
   solutions  without soil, can be used to identify essential elements in
   plants.
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	TECHNIQUE    Plant  roots  are  bathed  in aerated solutions of known
   mineral  composition.  A particular mineral, such as potassium, can be
   omitted to test whether it is essential.
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RESULTS    If  the  omitted  mineral is essential, mineral deficiency
   symptoms occur, such as stunted growth and discolored leaves.