Phytoremediation uses:
Phytoremediation integrates botanical processes with rhizosphere microbial ecology for contaminant removal, transformation, containment or detoxification using living plants and their associated microbiome. Roots actively exude low-molecular-weight organic acids such as citrate, malate, oxalate, sugars like glucose, amino acids and flavonoids that function as chemoattractants recruiting plant-growth-promoting rhizobacteria including Rhizobium, Pseudomonas fluorescens, Burkholderia and mycorrhizal fungi like Glomus that colonize root surface and interior, forming beneficial biofilm carrying catabolic genes for pollutant mineralization. Plant contributions encompass uptake of water-soluble organics via transpiration stream, translocation, sequestration in vacuoles mediated by tonoplast transporters, enzymatic transformation via cytochrome P450 monooxygenases, glutathione S-transferases, dehalogenases and peroxidases, plus hydraulic control preventing plume migration through high evapotranspiration rates 5 to 10 liters per day per mature poplar. Associated microbes enhance bioavailability through biosurfactant production, siderophore mediated iron competition, and mineralize petroleum hydrocarbons to carbon dioxide while plant supplies habitat and oxygen via aerenchyma. Animals do not actively contribute to primary mechanism; purely microbial approach excluded because phytoremediation definition inherently requires plant component providing photosynthetically driven solar remediation engine.
Ref: Pilon-Smits Phytoremediation Annual Review Plant Biology 2005; EPA Phytoremediation overview 2000; PubMed plant-microbe interaction.