Aims: Using rhizobacteria as plant growth-promoting agents for improving heavymetal phytoremediation processes in contaminated soil has attracted a lot of attention mainly because of their eco-friendliness. The aim of this study was the evaluation of lead phytoremediation by Carthamus tinctorius improved with the isolated and molecularly identified lead-resistant rhizobacteria. Methods and Results: Rhizobacteria were isolated from C. tinctorius root and was identified using macroscopic and microscopic characteristics, biochemical testing and PCR. Then, the indole acetic acid production and phosphate-solubilizing activity were determined. Finally, the amount of lead in the plant was measured by atomic absorption method. Five strains of Bacillus cereus, Bacillus muralis, Bacillus sp., Pseudomonas fluorescens and Brevibacterium frigoritolerans with the ability of mineral phosphate solubilizing, high levels of indole acetic acid production and resistance to lead were isolated from the rhizosphere of C. tinctorius. The amount of produced indole acetic acid and the level of phosphate solubilizing by the isolates were 7.1-69.54 µg ml −1 and 91-147.3 µg ml −1 respectively. Lead assimilation in aerial part of safflower ranged from 925 to 2175 ppm. P. fluorescens and B. cereus strains had the highest effect on Lead assimilation with 2175 and 1862 ppm respectively. Conclusions: The results showed that different bacterial treatments influenced the rate of lead absorption by C. tinctorius exposed to lead stress. Significance and Impact of the Study: Use of rhizosphere isolates of C. tinctorius can improve phytoremediation capability and lead absorption in leadcontaminated soil.

Cockroaches are the most resistant urban and domestic pests in the world. Hence, investigations into alternative control strategies such as the use of active compounds of plants against this insect pest are important. In this study, Francoeuria undulata (L.) plants were collected from Isfahan province, Iran, and then the essential oil of the aerial parts of the plant was extracted by hydro-distillation. Plant essential oil was analyzed using GC/MS. The German cockroach, Blattella germanica L. (Blattodea: Ectobiidae), were obtained from the Tehran University of Medical Sciences. Different concentrations of F. undulata essential oil were prepared in acetone, and contact and repellency tests were carried out on German cockroaches. Moreover, 40 male rats were divided into 4 groups including 1 Control and 3 treated groups that received F. undulata oil with 5%, 15%, and 30% v/v concentrations once daily for 10 days. The blood samples were collected and biochemical parameters were assayed in serum. Also, the liver tissue was isolated for histopathological examination. The major components of the essential oil were 1,8-cineole (26.02%), α-pinene (12.51%), Camphor (8.36%), and Camphene (5.03%). The results showed that the concentrations of 5%, 15%, and 30% v/v of F. undulata oil in 60 min of exposure had 100% insecticidal activity against the German cockroach. The repellency percentage of F. undulata oil at 5% concentration was not significant compared to the control, while the concentrations of 15% and 30% of essential oil showed a significant repellent effect on the German cockroach. Furthermore, the essential oil, at 5% concentration, was non-toxic to the livers of rats. The changes in the activities of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase were also detected in the treated rats. This finding revealed that the F. undulata essential oil has effective insecticidal activity against the German cockroach, making it a candidate for being considered in the management programmas of this pest.

Rhizospheric bacteria are among the beneficial soil microorganisms that improve plant growth. These bacteria increase plant growth through various mechanisms such as the production of various phytohormones and the ability to solubilize phosphate. The aim of this study was to investigate the effects of rhizosphere bacteria on the growth of Carthamus tinctorius to improve its physiological and biochemical indicators. Carthamus tinctorius seeds were inoculated with five isolates of rhizosphere bacteria and were then planted the seeds in pots. Subsequently, the physiological and biochemical parameters of the plants, including the rates of auxin production, phosphate dissolving, photosynthetic pigments and the contents of proline and malondialdehyde were measured. For this purpose, a factorial experiment were conducted using a completely randomized design with three replications. The ANOVA was performed and a comparison of the means was carried out using Duncan's multiple range test. The results indicated that the largest stem fresh weight, root fresh and dry weights observed in the treatments of using Pseudomonas fluorescens (auxin concentration of 23.55 μg/mL) and Bacillus muralis (auxin concentration of 22.27 μg/mL). In addition, all bacterial species increased the safflower seed germination rate compared to the control group. The largest malondialdehyde content was recorded in the treatment with Bacillus albus, and MDA content decreased in the treatments that produced larger amounts of auxin. In general, the finding of this research suggested that bacterial inoculation was capable to significantly affect the growth of safflower and improve its qualitative and quantitative growth parameters.