Factors Influencing the Evolution of Heavy Metal Hyperaccumulation in Plants

Abstract

My interest in the topic of bioremediation stemmed from a plant biotechnology seminar I was taking when this paper was assigned in my ecology and evolution class. Bioremediation is the use of biological agents, such as plants and microbes, to break down or remove pollutants from a contaminated site and has been touted as an environmentally-friendly method of cleaning up polluted areas. One potential application of bioremediation technology is the use of plants to remove heavy metals from contaminated soils through a process called phytoremediation. Hyperaccumulator plants have been heavily researched for phytoremediation use because of their ability to accumulate extraordinarily high levels of heavy metals in their tissues. These plants can thrive in soils contaminated with heavy metals at levels that would kill most plants. While hyperaccumulator plants have been extensively researched for phytoremediation, the reasons for the evolution of the hyperaccumulation trait have not been conclusively proven and are not frequently discussed. Thus, I took this opportunity to explore a facet of bioremediation that rarely receives attention. This review paper compiles and examines available research to evaluate five adaptive advantage explanations hypothesized to have influenced the evolution of the hyperaccumulation trait in plants.