Chapter 6 - Arbuscular Mycorrhizal Fungi and Metal Phytoremediation: Ecophysiological Complementarity in Relation to Environmental Stress

Abstract

Recent investigative interests focusing on plants and their allied soil-symbionts would suggest an important and multilateral impact of soil microbes in plant nutrient uptake and the regulation of soil nutrient availability. Focusing especially on the arbuscular mycorrhizal (AM) fungi, this chapter examines the primary mechanisms by which plant–soil interactions shape plant stress tolerance in relation to metal stress (i.e., from deficiency to toxicity conditions), and further outlines how these properties could be applied toward the phytoremediation of metal-polluted environments. Core mechanisms to be addressed include: enhanced metal/nutrient uptake, metal/nutrient biosorption and precipitation, and soil particulate micro- and macroaggregation. Biochemical pathways and plant physiological effects are emphasized. Thereafter, these multilateral effects are examined in an eco-physiological depiction of the dynamics of AM-symbiosis as a function of plant metal stress tolerance along with some of the ecophysiological boundaries in upscaling these processes (e.g., relating to the cost of maintaining the symbiotic infrastructure of the mycorrhizal fungi and the burden of metal stress at the scale of landscape remediation). Overall, the successful integration of any such processes into field-level applications hinges on identifying and then accounting for boundaries set by biogeochemical conditions of metal-contaminated environments and the ecophysiological factors underpinning plant–soil interactions.