Mention the methods to study the mineral requirements in plants.

(N/A) $\Rightarrow$ Julius von Sachs,a prominent German botanist,demonstrated for the first time that plants could be grown to maturity in a defined nutrient solution.
$\Rightarrow$ The technique of growing plants in a nutrient solution is known as hydroponics.
$\Rightarrow$ Since then,a number of improvised methods have been employed to try and determine the mineral nutrients essential for plants.
$\Rightarrow$ The essence of all these methods involves the culture of plants in a soil-free,defined mineral solution.
$\Rightarrow$ These methods require purified water and mineral nutrient salts.
$\Rightarrow$ After a series of experiments in which the roots of the plants were immersed in nutrient solutions and wherein an element was added/removed or given in varied concentrations,a mineral solution suitable for plant growth was obtained.
$\Rightarrow$ By this method,essential elements were identified and their deficiency symptoms were discovered.
$\Rightarrow$ Hydroponics has been successfully employed as a technique for the commercial production of vegetables such as tomato,seedless cucumber,and lettuce.
$\Rightarrow$ It must be emphasized that the nutrient solutions must be adequately aerated to obtain optimum growth.