Physiological responses of Polypogon monspeliensis L. in petroleum-contaminated soils

In a greenhouse study, decontamination capacity of the species Polypogon monspoliensis was investigatedfor detoxification of petroleum-polluted soils caused by sewage and waste materials of Tehran Petroleum Refinery. For this purpose, the amount of total oil and grease before and 45 days after transplanting one-month-old seedlings in the soils of five different treatments were measured. Pollution-free agricultural soil and contaminated soil were mixed together with the weight ratios of 1 to 9 (%10), 2 to 8 (%20), 3 to 7 (%30), 4 to 6 (%40), and 5 to 5 (%50). These were then compared with the amounts obtained from control treatment without vegetation, but with the same concentration of pollution. Findings demonstrated that the maximum reduction in the petroleum rate (84.85%) was related to the treatment of 10% contamination containing the plant. Increase in the shoot height in treatments 10% and 20% as well as the root dry and fresh weight in treatments 10% , 20% , and 30% shows that probably activity of more rhizosphere microorganisms of the plant in these treatments has led to the improvement in the growth of plant organs comparing to the treatments without pollution.