Cell and Tissue Journal

Abstract Aim: Plant-microbe interactions are considered to be important processes determining the efficiency of phytoremediation of petroleum pollution. The use of legume-Rhizobium is a suitable method for modification of petroleum-contaminated soil. The aim of this study was to evaluate the phytoremediation potential of Acacia– Rhizobium symbiosis in petroleum-polluted soil. Material and methods: The three-day acacia-seedlings were transferred to hydroponic medium and inoculated with rhizobium. Then, the 13-days seedlings transferred to polluted soil with different concentration of crude oil, that is; 0% as control and 1-5% (vol. /Wight), at the start and end of the 90-days period. Soil samples were analyzed for hydrocarbon removal (total hydrocarbon, n-tridecan, n-tetradecan and n-pantadecan) by GC-FID. Contents of Pb, Zn and Cd were measured with atomic absorption from soil and plant roots. The data were statistically analyzed with the help of SPSS11 and Duncan ‘test. Results: The results showed accumulation of heavy metal in plant roots and it’s reducing in soil. Hydrocarbon reduction was found over the course of the experiment in all treatments. The maximum removal was obtained in plants inoculated with rhizobium at 4% treatment, in which inoculated-acacia removed 97-100% of the hydrocarbons from soil. There fore inoculation Rubinia  pseudoacacia with Rhizobia are effective in removing TPHs and heavy metals from petroleum polluted soil. Conclusion: Based upon these results, Rubinia pseudoacacia L. inoculated with rhizobium can be used as lead and cadmium bioaccumulator in petroleum pollution and was selected for the phytoremediation of petroleum-contaminated soil.  

Abstract Aim: The aim of this study was to evaluate the effects of rhizobial inoculation on the anatomical parameters of clover under SO₂ pollution.
Material and methods: 31 day-old plants (no-inoculated and inoculated with two strains of Rhizobium) exposed to the different concentrations of SO₂ (0 as a control, 0.5, 1, 1.5 and 2 ppm) for 5 consecutive days for 2 hours per day. The anatomical parameters of 40 day-old plants were Then investigated.
Results: Under high SO₂ concentrations (1, 1.5 and 2ppm), length of the palisade cells and diameter of the spongy cells decreased in both leaf surfaces. Stomatal density decreased in adaxial epidermis and increased in abaxial epidermis. Also, stomatal opening increased in adaxial epidermis and decreased in abaxial epidermis. Trichome density in both leaf surfaces significantly increased in 1.5 and 2ppm SO₂ compared with control plants. Under 2 ppm, trichome length increased significantly in both leaf surfaces. Inoculation of clover with two strains of Rhizobium significantly reduced the negative effects of high SO₂ concentration.
Conclusion: The results indicate the negative effects of high concentrations of SO₂ air pollution on the some anatomical parameters and the positive effects of bacterial inoculation on resistance to air SO₂ pollution stress.

Abstract Aim: In this study, effects of Rhizobium on alfalfa plant growth under the SO₂ pollution were evaluated
Material and methods: 35 days plants (non-inoculated and inoculated with native or standard Rhizobium) exposed to the different concentration of SO₂ (0, 0.5, 1, 1.5 and 2ppm) for 6 consecutive days for 2 hours per day.
Results: Results indicated significant decrease of Leaf area, stem length, root depth and fresh and dry weight of leaf, stem and root under high concentration of SO₂. Number of leaves at all concentrations showed no significant change. Inoculation of alfalfa with Rhizobium significantly reduced the negative effects of high concentration of SO₂. In this study, positive effects of native bacteria were impressive.
Conclusion: The results indicate the harmful effects of high concentrations of SO₂ pollution on growth of plants and the positive effects of bacterial inoculation on resistance to air SO₂ pollution stress.