Total petroleum hydrocarbons (TPHs) is one of the most important environmental challenges. Phytoremediation of oil-polluted soil depends on microorganisms of the rhizosphere. This study attempts to evaluate the microbial impact of Zea mays rhizosphere during a 60 day period using three different treatments: control soil, oil-polluted soil and oil-polluted soil including fertilizer (NH₄No₃, K₂HPO₄). Then, the rhizosphere bacteria were identified. The results showed that CFU per gram of control soil was higher than other treated soils, an indication of oil stress on microbial population. In addition, more bacterial diversity was observed in soils and different bacteria were isolated from the soils. Finally, the most resistant bacteria to the oil pollution were assayed. The assay of isolates indicated that all of those separated from the oil-polluted soil have the ability to produce biosurfactant in different quantities. Further investigation must be carried out to optimize the degradation of oil by these isolates. 

Melissa officinalis is a medicinal plant belong to  lamiacea family.  This plant has been cultivated in many parts of the world due to its therapeutic effects. This study was conducted to improve antioxidant activities of proliferated shoots from tissue culture. The seeds of plant   were cultured in MS hormone free medium in order to obtain   seedlings. Then the  shoots were transfer to MS medium supplemented with 2 mg/ L  BAP.After 45 days salicylic acid (SA) was added to the medium at concentrations of 0, 50, 100 and 200 µM. The antioxidant activity and phenolics, flavonoids and rosmarinic acid content in proliferated shoots were evaluated 4,7,10 and 14 days after treatment. As a result the highest free radical scavenging and reducing power activity, as well as the highest value of total phenolic   and rosmarinic acid were observed in shoots   after 14 days of treatment with 100 µM salicylic acid. The elevated level of superoxide anion scavenging activity      and total flavonoids        were obtained from the shoots treated with 50 µM salicylic acid for 14 days. Over all treatment with100 µM salicylic acid for 14 days was better in order to antioxidant activity and compounds with recognized antioxidant activity.