جستجوی مقالات مرتبط با کلیدواژه "pseudomonas fluorescence" در نشریات گروه "آب و خاک"

In order to investigate the effects of application of sodium chloride, organic matter, and growth promoting bacteria on fresh and dry shoot weights and also concentration of some nutrients in aerial parts of spinach, a factorial experiment was conducted in a completely randomized design with three replications.  The treatments consisted of three levels of sodium chloride (control (S0), 2 (S2) and 4 (S4) g Na Cl kg-1 soil equivalent to 0.7, 8 and 16.8 dS/m, respectively), five levels of organic matter (control 0%(OM0), 0.5% (RS0.5) and 1% (RS1) % rice husk and 0.5% (Bi0.5) and 1% (Bi1) % rice husk biochar, w/w)  and two bacterial levels i.e. without (P0) and with bacteria (P1). Results showed that increasing salinity levels significantly increased spinach dry weight, but significantly decreased concentrations of N, P, Ca and Mg in aerial part, while concentration of Na increased. With the use of organic matter sources, fresh and dry weights of spinach shoot and con fluorescence [H1] centration of all nutrients increased significantly. Also, addition of Pseudomonas fluorescence significantly increased fresh and dry weights and concentration of nutrients of spinach aerial part .According to the results obtained in this study, it can be concluded that the use of organic matter as a soil amendment and rich source of nutrients can greatly increase concentration of nutrients in spinach. Also, addition of Pseudomonas fluorescence as a biofertilizer can improve spinach growth and increase concentration of some nutrients in spinach aerial part under salinity conditions. Application of organic matter and bacteria in salinity-free conditions increased concentration of nutrient and yield of plant. In general, further investigations under field conditions are necessary to verify the results of the present study.  [H1]?

The presence of petroleum compounds in the soil causes environmental problems. Therefore, attempting to remediate contaminated soils is important. The present study was aimed at studying the effects of (1) different levels of biochar obtained from urban wastes and (2) the bacterium that degrades petroleum hydrocarbons on levels of nutrients in amaranth. The treatments were raw oil (0 , 2.5, and 5%; weight-based), biochar obtained from urban waste compost and fresh urban wastes (0, 1, and 2 %, weight-based), and bacterium (with and without Pseudomonas ). The results showed that with increasing the biochar level, the plant growth was promoted, with the highest values for growth parameters in plants treated with highest level of biochar. The dry and fresh weights of shoots in treatments with Pseudomonas florescence had statistically considerable differences compared to those in the other treatments. Overall, with the application of biochar and Pseudomonas, the levels of nutrients studied increased, and the maximum nutrient level was observed in the plants treated with the highest level of biochar. The highest P level (0.37%) was detected in plants treated with P1B0Ba1, and the lowest (0.23%) in plants treated with P2BM2Ba1. Moreover, the highest K level (5.16%) was recorded in plants treated with P2BM2Ba1, while the lowest (2.15%) was measured in plants treated with P0BM1Ba0 (no biological factor). The highest levels of Ca and Mg were found in treatments with biochar. The highest levels of Fe (1200.33 mg/kg) and Mn (441.5 mg/kg) were found in plants treated with P0B0Ba1, which had the biological factor, while the lowest was recorded in treatments where Pseudomonas florescence was absent. Accordingly, in order to increase the efficiency of soil remediation, it is recommended that organic matters, especially biochar, and bacterial treatments be exploited so that favorable conditions could be provided for plant growth and development.

In this study an experiment was conducted based on completely randomized design in research greenhouse of Mohaghegh Ardabili University in 2014. Treatments consisted of inoculated seeds by Pseudomonas putida strains 1, 10, 19 and 150, Pseudomonas fluorescence strains 69 and 159, combination of strain 19 from Pseudomonas putida and strain 69 from Pseudomonas fluorescence and control (without inoculation). Plants were kept in greenhouse until six-leaf stage then exposed to low temperature stress (8 ºC temperature for 270 minutes during five consecutive days). After exposing plants to low temperature stress, traits such as seedling height and dry weight, photosynthetetic pigments, total carbohydrates, proline, membrane integrity, protein amount, catalase, peroxidase and poly phenol oxidase enzymes were measured. Results indicated that primingof okra seeds with plant growth promoting bacteria increased seedling height and dry weight, physiological and biochemical characteristics. Pseudomonas putida and Pseudomonas fluorescence increased cell membrane integrity via increase in leaf proline content, total soluble carbohydrates and antioxidant enzymes. The greatest promotion of seedling growth under low temperature was obtained by priming of seeds with Pseudomonas putida strain 150 and of Pseudomonas fluorescence strain 69.

The species of Pseudomonas genus show different levels of resistance to soil''s heavy metals pollution. Since، there exists is a relationship between heavy metal resistance and plasmid profile of bacteria، in this study، plasmid profile of Plant Growth Promoting Rhizobacteria (PGPR) Pseudomonas fluorescence isolates were studied in the presence of cadmium and zinc. The bacteria were initially isolated from soybean rhizosphere and characterized as based on biochemical and biological properties. Then، different concentrations of Zn and Cd، in the H. E. P. E. S and M. E. S solid mediums، were employed to evaluate the resistance of the isolates to these heavy metals. Based on the growth in the presence of Zn and Cd، the isolates were classified into 4 groups. Two isolates taken from each group were exposed to different concentrations of Zn and Cd for a period of 2 months. Then، the isolates were sub-cultured and their plasmids isolated using alkaline lysis procedure. The plasmid profile of isolates indicated that the toxic effect of the cadmium was higher than that of zinc even when at lower concentrations. At concentrations of cadmium، all the isolates lost their plasmids. Three isolates also showed multiple resistances to heavy metals.