Effect of Bacillus cereus strains on potassium and iron uptake from substrates containing muscovite and phlogopite

Beneficial soil microorganisms are important biological factors in improving take up micronutrient by plants. Microorganisms help the release of nutrients from soil minerals using different mechanisms. The use of plant growth promoting bacteria (PGPBs) for sustainable agriculture has increased tremendously in the last decades. This study was conducted to investigate the effect of two strains of Bacillus cereus on potassium and iron uptake by alfaalfa from substrates containing micaceous minerals (muscovite and phlogopite).
The greenhouse experiment was achieved using a completely randomized design in factorial arrangement with three replications. The treatments included four levels of nutrient solution (complete, iron- and potassium-free, potassium-free, and iron- free), two types of potassium bearing minerals (phlogopite and muscovite), three bacterial treatments (PTCC 1247, and PTCC 1665 and non-inoculated). The studied plants which were irrigated with four nutrient solutions during the growing seasons were harvested after 150 days of planting and potassium and iron of the shoots and roots were measured by flame photometry and atomic absorption spectrometery, respectively.
The results showed that the presence of bacteria strains resulted in increased shoot and root dry weights, and also take up of potassium and iron from studied substrates. The highest uptake of shoot potassium observed in the plants Cultivated at substrates containing muscovite and phlogopite and Nutrition with two nutrient solutions, complete and iron free. The highest uptake of root potassium observed at substrate containing phlogopite inoculated with strain PTCC 1247 and nutrient with nutrient solution iron free. The uptake of iron in plant roots was several folds greater than the shoot. Iron concentration in the roots of growing plants in phlogopite substrate was higher than muscovite. Plant inoculation with bacterial strains resulted in increased iron uptake in inoculated roots compared to non-inoculated ones. The obtained results showed the content of iron concentration in growing plants in phlogopite substrates was greater than substrates containing muscovite. The uptake of potassium and iron was different Due to different treatment Nutrient solution. The highest uptake potassium and iron were observed for plants cultivated at substrates containing muscovite and Nutrient with Complete nutrient solution.
The presence of bacteria in plant rhizosphere could release nutrients from soil minerals and lead to improve growth and yield of plants. In conclusion, the optimal use of useful type of bacteria could decrease chemical fertilizer application under greenhouse conditions.