Hydroponic culture

APPLICATION Hydroponic culture, where plants are grown in mineral solutions without soil, can be used to identify essential elements in plants.

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.

RESULTS If the omitted mineral is essential, mineral deficiency symptoms occur, such as stunted growth and discolored leaves.