ABSTRACT
This chapter discusses aspects related to the ecotoxicology of airborne pollutants. Physical leaf characteristics such as leaf thickness, mesophyll cell surface area, internal air space volume, cell wall thickness, and the volume of the aqueous matrix of the cell wall influence the eventual concentration of the pollutant and its dissolution products in the apoplast. Once the pollutant has penetrated as far as the mesophyll cell surface, it may be metabolized, sequestered, or excreted. Detoxification systems capable of protecting sensitive targets from the oxidative stress imposed by pollutants and their derivatives are common in plants, as in animals, and are subject to strict genetic control. The processes controlling differential resistance to pollutants are considered within the framework of a conceptual model. Pollutant levels that exceed the capacity of avoidance/tolerance mechanisms will result in cellular destabilization—an effect that underpins changes in the performance of the individual and shifts in the genetic composition of both populations and communities.
