The concept of mineral plant nutrient in the light of evolution

The concept of mineral plant nutrient has been the subject of a long debate. Here, we suggest that an updated discussion on this issue requires considering three dimensions. The first one is ontological as it refers to the fundamentals that underlie the category of being a mineral plant nutrient, the second one refers to the practical rules helping to assign a given element to that category, while the third dimension implies the consequences of those rules for human activities. We highlight the idea that the definition of what is a mineral plant nutrient can be enriched by incorporating an evolutionary perspective, thus giving biological insight and helping to integrate information from different disciplines. Following this perspective, mineral nutrients can be contemplated as the elements adopted and/or retained, along evolution, for survival and successful reproduction. We suggest that the operational rules stated in both early and recent works, while highly valuable for their original purposes, will not necessarily account for fitness under the conditions prevailing in natural ecosystems where elements were adopted and are retained -as a result of natural selection processes- covering a wide spectrum of biological activities. We outline a new definition that considers the mentioned three dimensions.