Heavy Metals Affect Yield, Essential Oil Compound, and Rhizosphere Microflora of Vetiver (Vetiveria zizanioides Linn. nash) Grass

The effects of heavy metals [chromoium (Cr), cadmium (Cd), lead (Pb) and nickel (Ni)] on the yield, khusimol content in the essential oil, accumulation of metals, and rhizosphere microflora of vetiver (Vetiveria zizanoides) were studied in a pot experiment. The shoot yield and khusimol content in oil of vetiver were enhanced by the application of moderate amount of metals to soils. The application of Cr, Pb, and Ni had deleterious effects on the root and essential oil yield. The application of high levels of metals to soil had harmful effects on the bacterial and fungal counts in the rhizosphere. The concentrations of metals such as Cr, Cd, Pb, and Ni in shoot and root tissues were significantly enhanced by the application of those metals to soils. It can be concluded that the vetiver could be used as a promising crop for revegetation, soil remediation, and production of better quality essential oil in metal-contaminated soils.