Evaluation the Growth Potential of Artichoke (Synara scolymus L.) and Milk thistle (Sylibum marianum L.) in Petroleum-contaminated Soil

Petroleum hydrocarbons are one of the most common pollutants groups in the environment and threaten the human, animals and plants health. Phytoremediation is a method for cleaning the contaminated areas. Medicinal plants because of their defense mechanisms able to resist and thwart destructive effect of stressors. Some plants have better resistance, including Artichoke (Cynara scolymus L.) and Milk Thistle (Silybum marianum L.); from Asteraceae family that has polyphenolic compounds with antioxidant properties and hepatoprotectors. To evaluation the growth potential of Artichoke and Milk Thistle in petroleum-contaminated soil, an experiment in a completely randomized design was done with 6 levels of gas oil and 3 replications in Gorgan University of Agricultural Sciences and Natural Resources. The results showed that, gas oil hydrocarbon had a significant effect at %1 on germination percent of seed and indexes involved in seedling growth including plant height, length, and width, fresh and dry weight of artichoke leaf. In Milk Thistle, gas oil had no significant effect on germination percent. Opposite to that, significant effect at %1 on growth indexes was observed. The maximum germination percent in Artichoke and Milk Thistle seeds was observed in 20 and 10 g/kg gas oil, respectively and the minimum of germination percent was observed in seeds samples that treated with 80 g gas oil per kg soil. Artichoke seedlings were more tolerance than Milk Thistle to the contaminated soil as better growth was observed in this condition. Generally, it seems that these two valuable medicinal plants had relatively resistance to the gas oli pollution and are suggestible to use in oil contaminated soil for cleaning purpose