Nutrient metal elements in plants

Plants need many different metal elements for growth, development and reproduction, which must bemobilized from the soil matrix and absorbed by the roots as metal ions. Once taken up by the roots,metal ions are allocated to different parts of the plant by the vascular tissues. Metals are naturallypresent in the soil, but human activities, ranging from mining and agriculture to sewage processing andheavy industry, have increased the amount of metal pollution in the environment. Plants are challengedby environmental metal ion concentrations that fluctuate from low to high toxic levels, and havetherefore evolved mechanisms to cope with such phenomena. In this review, we focus on recent datathat provide insight into the molecular mechanisms of metal absorption and transport by plants, alsoconsidering the effect of metal deficiency and toxicity. We also highlight the positive effects of somenon-essential metals on plant fitness.