In the second of three Teaching Tools in Plant Biology spanning the topic of Plant Nutrition, we examine how macronutrients affect plant growth. Specifically, we look at (1) the availability of nutrients in the soil along with the effects of soil microbes and physical properties on their availability; (2) nutrient uptake from the external environment, across plasma membranes and into plant cells; (3) in some cases, the assimilation of the nutrient into organic molecules; (4) the distribution and redistribution of nutrients throughout the plant; and (5) regulation of these processes. In parallel, we examine the genetic basis of a plant’s nutrient use efficiency (NUE) and evaluate strategies by which to replenish nutrients that growing plants extract from soil.
Much of the discussion concerns the mechanisms by which nutrients enter, move through and are used by the plant, but the very important considerations about the impacts of chemically-synthesized fertilizers are also addressed. An extensive set of discussion questions to stimulate inquiry are included in the teaching guide.