4.1.1 Phytosequestration
Phytosequestration is a phenomenon in which the bioavailable contaminants trapped
from the root systems and their entry into the root are reduced by several phytochemical complexations. Inhibition by transport proteins on the root membranes
successfully prevents contaminant entry. The vacuolar storage of root cells also
enhances the sequestration of contaminants into the vacuoles.
4.1.2 Rhizodegradation
Rhizosphere degradation is a process in which the plants stimulate the activities of
root-associated soil microbial communities for contaminant degradation. Many of
the aquatic plants also stimulate the microbial degraders, as proved in the case of
atrazine by hornwort plants (Salt et al. 1995a, b; Sarwar et al. 2017). This process
may also be referred to as phytostimulation.
4.1.3 Phytohydraulics
In phytohydraulics, the plants capture, transport, and transpire water from the
environment to control the pollutants by hydrology. This mechanism does not
degrade the contaminant.
4.1.4 Phytoextraction
The phenomenon of transferring the contaminants from the soil to the aboveground
level by employing plants is called phytoextraction. The plants may either uptake or
absorb the contaminant via the root system, and then transfer it to the shoot system,
from which it can either be extracted as metal or create energy by burning.
4.1.5 Phytovolatilization
After taking up the bioavailable contaminants through the root system, the plant
transfers them to the body of the plant above ground level, where it is digested or
converted into the volatile form and will soon be transpired out of the plant system,
along with water vapor, through the leaves and into the atmosphere. This phenomenon is called the phytovolatilization process.
4 Recent Advances in Phytoremediation of Toxic Metals from Contaminated. . .
89
Phytosequestration is a phenomenon in which the bioavailable contaminants trapped
from the root systems and their entry into the root are reduced by several phytochemical complexations. Inhibition by transport proteins on the root membranes
successfully prevents contaminant entry. The vacuolar storage of root cells also
enhances the sequestration of contaminants into the vacuoles.
4.1.2 Rhizodegradation
Rhizosphere degradation is a process in which the plants stimulate the activities of
root-associated soil microbial communities for contaminant degradation. Many of
the aquatic plants also stimulate the microbial degraders, as proved in the case of
atrazine by hornwort plants (Salt et al. 1995a, b; Sarwar et al. 2017). This process
may also be referred to as phytostimulation.
4.1.3 Phytohydraulics
In phytohydraulics, the plants capture, transport, and transpire water from the
environment to control the pollutants by hydrology. This mechanism does not
degrade the contaminant.
4.1.4 Phytoextraction
The phenomenon of transferring the contaminants from the soil to the aboveground
level by employing plants is called phytoextraction. The plants may either uptake or
absorb the contaminant via the root system, and then transfer it to the shoot system,
from which it can either be extracted as metal or create energy by burning.
4.1.5 Phytovolatilization
After taking up the bioavailable contaminants through the root system, the plant
transfers them to the body of the plant above ground level, where it is digested or
converted into the volatile form and will soon be transpired out of the plant system,
along with water vapor, through the leaves and into the atmosphere. This phenomenon is called the phytovolatilization process.
4 Recent Advances in Phytoremediation of Toxic Metals from Contaminated. . .
89