1.5.2 Phytodegradation or Phytotransformation and Phytostimulation
Phytodegradation, or phytotransformation, is the process in which the plants uptake,
store, and degrade or transform complex organic pollutants to a lesser harmful
substance and simpler organic compounds. Phytostimulation is also known as
plant-assisted bioremediation, i.e., the stimulation which is assisted by microbial
or fungal. The enzyme or exudates are released to the root zone. Soil organic
contaminants can be degraded directly by plant enzyme systems or indirectly by
improving living conditions for the soil microorganisms, to enhance their activity
and accelerate the degradation of pollutant [45]. The indirect phytotransformation is
called as phytostimulation [46]. Phytodegradation process involves the uptake of the
contaminants, storing and degrading the contaminants within the tissue. The contaminants can be absorbed by the plant, and the plant enzymes break down the
contaminants [47]. Figure 2 presents the schematic representation of
phytodegradation process.
Plant-assisted microbial degradation or phytostimulation or rhizodegradation is
also categorized as phytotransformation. The root zone of plants is the zones for
accelerated biodegradation, due to presence of consortia of microorganisms in
rhizosphere, the soil-root interface. Growing of the root stimulates the proliferation
of the microbes which utilizes the exudates of plants. The exudates act as a source of
carbon and energy [48]. Further, the proliferation of microbes facilitates in the
uptake and degradation of components, e.g., hydrocarbon [49]. The rhizosphere
region is the soil area of the plant, and it secretes substances that can accelerate the
rate of degradation of the organic contaminants. The rhizosphere has 100 times
greater quantity of microbes than the surface because of the various nutrients like
amino acids, enzymes secreted by the plant, sugars, etc. present in the soil. It also has
Fig. 2 Phytodegradation
Phytoremediation of Soil for Metal and Organic Pollutant Removal
51
Phytodegradation, or phytotransformation, is the process in which the plants uptake,
store, and degrade or transform complex organic pollutants to a lesser harmful
substance and simpler organic compounds. Phytostimulation is also known as
plant-assisted bioremediation, i.e., the stimulation which is assisted by microbial
or fungal. The enzyme or exudates are released to the root zone. Soil organic
contaminants can be degraded directly by plant enzyme systems or indirectly by
improving living conditions for the soil microorganisms, to enhance their activity
and accelerate the degradation of pollutant [45]. The indirect phytotransformation is
called as phytostimulation [46]. Phytodegradation process involves the uptake of the
contaminants, storing and degrading the contaminants within the tissue. The contaminants can be absorbed by the plant, and the plant enzymes break down the
contaminants [47]. Figure 2 presents the schematic representation of
phytodegradation process.
Plant-assisted microbial degradation or phytostimulation or rhizodegradation is
also categorized as phytotransformation. The root zone of plants is the zones for
accelerated biodegradation, due to presence of consortia of microorganisms in
rhizosphere, the soil-root interface. Growing of the root stimulates the proliferation
of the microbes which utilizes the exudates of plants. The exudates act as a source of
carbon and energy [48]. Further, the proliferation of microbes facilitates in the
uptake and degradation of components, e.g., hydrocarbon [49]. The rhizosphere
region is the soil area of the plant, and it secretes substances that can accelerate the
rate of degradation of the organic contaminants. The rhizosphere has 100 times
greater quantity of microbes than the surface because of the various nutrients like
amino acids, enzymes secreted by the plant, sugars, etc. present in the soil. It also has
Fig. 2 Phytodegradation
Phytoremediation of Soil for Metal and Organic Pollutant Removal
51