Mutagenesis of the Bacillus edaphicus Strain NBT and Its Effect on Growth of Chili and Cotton

<正> A strain NBT capable of dissolving silicate minerals and promoting plant growth was treated with UV+LiCl. Thirty-two mutants tolerable to 2% NaCl solution were obtained. However, through the survival experiments in high osmatic pressure, high temperature and different acidities, two mutants of NBT-6 and NBT-19 were finally obtained. They could survive from 10% NaCl solution and tolerate 55℃, acidic (pH 4) and alkalic (pH 10) conditions. The mutants had the same ability to release K from silicate minerals as the starting strain NBT. Pot experiments with chili and cotton showed that both the mutants developed in the rhi-zosphere soils. The available P and K contents in the rhizosphere soils and plant biomass increased through inoculating these bacteria.