The mineral elements present in the soil enter into the plants through roots. All the elements, which enter into the plants, may not be essential for their surival. Some are absorbed and accumulated by plants because they are present in the soil in excess amounts. For exmaple, some plants absorb and accumulate Selenium while others store gold or other minerals, but they are not essential. In fact, more then 60 elements have been found to be present in different plants but only a few are essential for the survival. Thus, an essential element is the which must be directly involved in the metabolism of plant and must cause specific deficiency symptom if not supplied to the plant from external medium.
