genetically and metabolic consistency as compared to wild type have been provided
for HRs applications in phytoremediation process (Gujarathi et al. 2005; Georgiev
et al. 2007). Transformed roots are amenable to genetic modifications and may
advance the characterization of genes that regulate the phytoremediation potentials
of plants. In addition, the expression of appropriate genes in plant root system
improves the rhizo-degradation of extremely recalcitrant compounds, for example,
PAHs and PCBs, etc. (Abhilash et al. 2009; Gerhardt et al. 2009).
Another advantage of using HRs for studying about the phytoremediation system
is their capability to develop large quantities of root exudates that are consisting of
enzymes and few kinds of metal-chelating substances that may detoxify or cutoff the
adverse organic and inorganic pollutants in the soil (Bais et al. 2006; Doty 2008;
Gujarathi et al. 2005). Flocco et al. (1998) reported in A. lapathifolia and concluded
that roots comprise major levels of peroxidase enzymes (E.C. 1.11.1.7) that are
recognized to be concerned with the detoxification process of phenols and some
other aromatic molecules. Among all the toxic compounds that contaminate the
water and agricultural soils, polychlorinated biphenyls (organic chlorine molecules)
and some inorganics, in particular, HMs and radionuclides (an atom that has excess
nuclear energy) have been the important issues in phytoremediation investigation.
These important characteristics made HRCs have been referred to as an exceptional
experimental model to remediate organic and inorganic pollutants because of their
biochemical and genetic stability through cost-effective phytoremediation treatments as phytostabilization, phytovolatilization, rhizofiltration, phytodegradation,
and phytoextraction (Upadhyay et al. 2019; Majumder and Jha 2012). Several
reports have concluded and reported that HRs originated from various kinds of
plant species can be exploited for the treatment of different organic and inorganic
pollutants including heavy metals, dyes, ions, pesticides, excess nutrients, and
solvents (Fig. 2.1).
2.1 Phytoremediation for Heavy Metal Degradation
HMs are characterized as metallic components that have comparatively highly thick
contrary to water (Tchounwou et al. 2012). There are 59 elements categorized as
HMs on the terrestrial crust, which are discharged into the environment through
man-made activities or by natural constituents. Among those five HMs viz., copper,
chromium, cadmium, zinc, and lead are believed to be extremely harmful (Shaban
et al. 2016). HMs may cause the brain to injure and also creates several other
disorders in living beings. These HMs cannot be humiliated easily and their remediation from the environment is very essential. In this situation, the application of
advanced biological methods especially HRCs is the only alternative and gives more
attention since they are believed to be renewable, eco-friendly, and produce valuable
credentials for enzymatic reactions (Jadhav et al. 2009).
HMs contamination of soils is one of the particularly relevant environmental
issues throughout the world (Doumett et al. 2008; Nouri et al. 2006). Consequently,
34
A. K. Moola et al.
for HRs applications in phytoremediation process (Gujarathi et al. 2005; Georgiev
et al. 2007). Transformed roots are amenable to genetic modifications and may
advance the characterization of genes that regulate the phytoremediation potentials
of plants. In addition, the expression of appropriate genes in plant root system
improves the rhizo-degradation of extremely recalcitrant compounds, for example,
PAHs and PCBs, etc. (Abhilash et al. 2009; Gerhardt et al. 2009).
Another advantage of using HRs for studying about the phytoremediation system
is their capability to develop large quantities of root exudates that are consisting of
enzymes and few kinds of metal-chelating substances that may detoxify or cutoff the
adverse organic and inorganic pollutants in the soil (Bais et al. 2006; Doty 2008;
Gujarathi et al. 2005). Flocco et al. (1998) reported in A. lapathifolia and concluded
that roots comprise major levels of peroxidase enzymes (E.C. 1.11.1.7) that are
recognized to be concerned with the detoxification process of phenols and some
other aromatic molecules. Among all the toxic compounds that contaminate the
water and agricultural soils, polychlorinated biphenyls (organic chlorine molecules)
and some inorganics, in particular, HMs and radionuclides (an atom that has excess
nuclear energy) have been the important issues in phytoremediation investigation.
These important characteristics made HRCs have been referred to as an exceptional
experimental model to remediate organic and inorganic pollutants because of their
biochemical and genetic stability through cost-effective phytoremediation treatments as phytostabilization, phytovolatilization, rhizofiltration, phytodegradation,
and phytoextraction (Upadhyay et al. 2019; Majumder and Jha 2012). Several
reports have concluded and reported that HRs originated from various kinds of
plant species can be exploited for the treatment of different organic and inorganic
pollutants including heavy metals, dyes, ions, pesticides, excess nutrients, and
solvents (Fig. 2.1).
2.1 Phytoremediation for Heavy Metal Degradation
HMs are characterized as metallic components that have comparatively highly thick
contrary to water (Tchounwou et al. 2012). There are 59 elements categorized as
HMs on the terrestrial crust, which are discharged into the environment through
man-made activities or by natural constituents. Among those five HMs viz., copper,
chromium, cadmium, zinc, and lead are believed to be extremely harmful (Shaban
et al. 2016). HMs may cause the brain to injure and also creates several other
disorders in living beings. These HMs cannot be humiliated easily and their remediation from the environment is very essential. In this situation, the application of
advanced biological methods especially HRCs is the only alternative and gives more
attention since they are believed to be renewable, eco-friendly, and produce valuable
credentials for enzymatic reactions (Jadhav et al. 2009).
HMs contamination of soils is one of the particularly relevant environmental
issues throughout the world (Doumett et al. 2008; Nouri et al. 2006). Consequently,
34
A. K. Moola et al.