Plant Nutrition 3: Micronutrients and metals

Abstract

Summary In the third of three lessons spanning the topic of Plant Nutrition, we examine how micronutrients affect both plants and humans. Specifically, we examine the functions of the nine essential micronutrients Fe, Cu, Zn, Mn, Mo, Ni, B, Si and Cl with a particular focus on the unique chemistry of the metal micronutrients. Because the optimal concentration range of most micronutrients is quite narrow in the plant body, plants employ strategies at both the low end and high end of the optimal nutrient range to avoid deficiency and toxicity effects, although some plants hyperaccumulate micronutrients for defensive purposes. Efforts to improve human nutrition through biofortification, particularly of Fe, Zn and Se are discussed. We further examine how plants and people are affected by the toxic elements As, Cd and Al, and efforts to alleviate their harm through our understanding of plant micronutrition.