Study On Promoting Effects Of Growth-promoting Rhizobacteria From Pseudostellaria Heterophylla

Objective: The studies on the effects of growth-promoting rhizobacteria from Pseudostellaria heterophylla on the growth of Pseudostellaria heterophylla and intercropping maize, the physical and chemical properties of the cultivation soil, and pathogen of Pseudostellaria heterophylla, which would provide the evidences for the production of microbial fertilizer of Pseudostellaria heterophylla. Methods: Five rhizobacteria, namely KTS-1-1(A, had the abilities of the antagonism against root rot pathogen and dissolving potassium), TR-10J(B, had the ability of phosphate-solubilizing), ATS-1-1(C, had the ability of nitrogen fixing), ATR-2-3(D, had the ability of nitrogen fixing) and PTS-2-1(E, had the ability of phosphate-solubilizing were applied to the trials of Pseudostellaria heterophylla and maize growth pot, maize seeds germination, the assay of the soil physical and chemical characteristics and the inhibitory test of rhizobacteria against pathogen, so that the optimal combination of rhizobacteria was achievd for the production of microbial fertilizers of Pseudostellaria heterophylla. Results: ①The experiment of growth pot of the Pseudostellaria heterophylla showed that the combinations of A1B2C1D1E1, A1B2C1D1E1, A1B1C1D2E1, A2B1C2D2E2 had the most obvious effects on root length, fresh weight of roots, dry weight of roots, number of roots of Pseudostellaria heterophylla, respectively. For the effects of five growth-promoting rhizobacteria on saponins content of Pseudostellaria heterophylla, the combinations of A1B2C1D2E2, A1B1C1D1E1, A1B1C1D1E2 were higher than others, the corresponding values of saponins contents were 0.0762%, 0.0752% and 0.0744%, respectively. The combinations of A2B2C1D2E2, A2B2C2D2E1, A1B1C1D2E2 had the significant effects on the total nitrogen, the effective phosphorus, the effective potassium in the soil of cultivation, respectively. ②The experiment of growth pot of maize showed that the combinations of A2B1C2D1E2, A2B1C2D1E2, A1B1C1D2E2, A1B1C2D2E1, A2B1C1D2E1 had the most obvious effects on the fresh weight of stem leaf, dry weight of stem leaf, length of stem leaf, fresh weight of root, dry weight of root, respectively. Compared with the control, there existed statistical significance(p<0.05) for all the above combinations. The combinations of A1B2C1D1E1, A1B1C2D1E2, A2B1C2D2E1, A1B2C1D1E1, A2B2C2D1E1, A2B2C1D1E1 had the most obvious effects on the total nitrogen, phosphorus, potassium of stem leaf and the total nitrogen, phosphorus, potassium of roots. ③The experiment of maize seed germination showed that the combinations of A1B1C2D2E2, A2B1C1D2E1(or A2B2C1D1E1), A1B1C1D1E1, A1B2C2D2E2, A1B1C2D2E2, A1B2C2D2E1, A2B2C2D1E1, A1B1C2D1E2 and A1B2C2D2E2 had the most obvious effects on germination potential, germination rate, dehydrogenase activity, seedling length, radicule length, hypocotyls length, the number of fibrous roots, dry weight of seedlings and dry weight of roots, respectively. There existed the interactions among five growth-promoting rhizobacteria on seedling length, radicule length, hypocotyls length, the number of fibrous roots, dry weight of seedlings and dry weight of roots. ④The experiment of the assay of the soil properties showed that the combinations of A2B1C1D2E2, A1B1C2D1E2, A2B2C2D1E2 had the most obvious effects on the total nitrogen, the effective phosphorus, the effective potassium of the soil, respectively. Compared with the control, there existed statistical significance(p<0.05) for all the above combinations. For the contents of the total nitrogen, the effective phosphorus and the effective potassium in the soil, those of A2B2C2D2E1 and A1B2C2D2E2 were higher than control. ⑤The inhibitory experiment of Growth-promoting rhizobacteria from Pseudostellaria heterophylla showed that four pathogenic fungi were isolated from Pseudostellaria heterophylla diseased root, namely TZSLF, RPF-2, RGF-10 and TZSLV, which were identified as Fusarium sp., Verticillium sp., Fusarium sp. and Bionectria ochroleuca, respectively. The inhibitory rate of KTS-1-1 reached 54%~70%, while those of ten fungicides was between 2%~77%. Conclusion: ①The combinations of A1B1C1D2E1 could promote the growth of Pseudostellaria heterophylla and maize, especially increase the dry weight of roots of Pseudostellaria heterophylla, and improve the contents of the soil properties including the total nitrogen, the effective phosphorus and the effective potassium. ②The inhibitory rates of KTS-1-1 against pathogenic fungi were higher than those of most fungicides. ③The pathogens for the root rotten disease of Pseudostellaria heterophylla were identified as Fusarium sp., Verticillium sp. and Bionectria ochroleuca.