Page 246 - Plant-Based Remediation Processes

Chapter 12
Transgenic Approaches to Enhance
Phytoremediation of Heavy Metal-Polluted Soils

Pavel Kotrba

12.1 Introduction

Contamination of soils and sediments with toxic heavy metals contributes to serious
environmental, economic, and health problems. Plants are predominant organisms
in most ecosystems and have the natural ability to take up toxic metals along with
micronutrients (Sarwar et al. 2010; Kabata-Pendias 2011). A promising and rela-
tively new technology, referred to as phytoremediation, offers benefits of affordable
and environmentally sustainable in situ bioremediation method (Pilon-Smits 2005;
Macek et al. 2008; Doty 2008; Kotrba et al. 2009; Aken et al. 2010; Bhargava et al.
2012; Rajkumar et al. 2012). The phytoremediation approaches considered partic-
ularly suitable for reclamation of metal-polluted soils are phytoextraction and
phytovolatilization. Phytoextraction aims at use of metal-accumulating plants that
concentrate the pollutant in aboveground harvestable parts. Phytovolatilization is a
process by which plants allow the accumulated pollutant to evaporate through their
leaf surface when converted in planta to volatile forms. There are also other tactics
relevant to phytoremediation of inorganic xenobiotics. In phytostabilization, plants
are employed to prevent migration of contaminants to sites where they may pose a
danger, and in rhizofiltration plant roots are used to absorb, concentrate, and/or
precipitate pollutants from contaminated effluents.
Soils with abnormally high concentrations of some of the elements vary widely in
their effects on different plant species. Some plants, including several metallophyte
crops such as Indian mustard (Brassica juncea) or sunflower (Helianthus annuus),

This chapter is dedicated to the memory of my colleague, Professor Martina Mackova ´
(1965–2012).
P. Kotrba (*)
Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague,
Technicka ´ 5, Prague 166 28, Czech Republic
e-mail: pavel.kotrba@vscht.cz

D.K. Gupta (ed.), Plant-Based Remediation Processes, Soil Biology 35, 239
DOI 10.1007/978-3-642-35564-6_12, # Springer-Verlag Berlin Heidelberg 2013