Abstract:

This research investigated the effects of Bacillus subtilis and actinomycetes on salt tolerance of plants. Specifically， the effects of B. subtilis and three actinomycetes （Roseosporus 2-5， Lavendulae 6-3 and Cinereus 1-6） on seed germination and seedling growth of Bidens pilosa and Eclipta prostrata under salt stress were studied using a petri dish method. It was found that： 1） B. subtilis and the three actinomycetes increased the seed germination rate of B. pilosa at salt concentrations of 25-75 mmol·L^-1， but the four microbial solutions had little effect on the seed germination rate of E. prostrata. 2） B. subtilis and the three actinomycetes had little effect on the root length of B. pilosa under salt stress， and had different degrees of growth promotion effect on the root length of E. prostrata. 3） The four microbial solutions had little effect on the stem length of B. pilosa， but significantly promoted intestinal stem growth of E. prostrata under salt stress， with B. subtilis and the 3 ascomycetes increasing the stem length of this species by 30.56%， 28.57%， 26.47% and 24.24%， respectively at 100 mmol·L^-1 salt concentration. 4） Treatment with B. subtilis and the three actinomycetes at the various salt concentrations reduced the dry weight of B. pilosa， compared to seedlings germinated in a sterile solution， but the dry weight of E. prostrata was increased to different degrees in the same conditions. In summary， B. subtilis and the three actinomycetes had significant growth promotion effects on seed germination rate of B. pilosa and root length， stem length and dry weight of E. prostrata under salt stress， which was beneficial to adaptation of B. pilosa and E. prostrata seedlings to salt stress.

Key words: Bacillus subtilis, actinomycetes, salt stress, seed germination, seedling growth