Key points are not available for this paper at this time.
Broadly, the approach which researchers have adopted in this review has been to ask the following questions about mineral nutrients: What properties make them essential. How are they obtained. How effectively are they used. We shall not be considering two most important, but frequently reviewed, aspects of the subject, namely biological fixation of N/sub 2/ and its assimilation and mechanisms of membrane transport.
Clarkson et al. (Sun,) studied this question.