Biotechnology Bulletin ›› 2023, Vol. 39 ›› Issue (6): 274-285.doi: 10.13560/j.cnki.biotech.bull.1985.2022-1226

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Growth Promoting of Pinus massoniana Seedlings Regulated by Rhizosphere Phosphate-solubilizing Paraburkholderia spp.

XU Hong-Yun1(), LV Jun2, YU Cun2()   

  1. 1. College of Eco-Environment Engineering, Guizhou Minzu University, Guiyang 550025
    2. College of Forestry, Guizhou University, Guiyang 550025
  • Received:2022-10-08 Online:2023-06-26 Published:2023-07-07
  • Contact: YU Cun E-mail:xhyplant@126.com;chifengyucun@163.com

Abstract:

It is aimed to screen phosphate-solubilizing rhizobacteria(PSB)and to clarify its growth-promoting effect on Pinus massoniana seedlings and the mechanism. The soil-dilution plate method was used to isolate and purify the PSB strains. The PSB strains were identified by morphology and 16s rDNA sequencing methods. Finally, the masson pine seedlings were inoculated with PSB strains for 60 d, then the seedling growth and physiological indexes, soil physical and chemical properties, and rhizosphere bacterial community were determined. The results showed that three PSB strains(WJ10, WJ25 and WJ41)with strong phosphate-solubilizing abilities were isolated from the P. massoniana rhizosphere soil and belonged to Paraburkholderia spp. The three PSB strains had the strongest phosphate-solubilizing abilities to aluminum phosphate, followed by tricalcium phosphate, calcium monophosphate and ferric phosphate. Based on the pot experiment, the three PSB strains effectively promoted seedlings growth, with the best effects on the seedling height and root length promotion for WJ25, followed by WJ41 and WJ10. The main mechanisms of seedling promotion of the three PSB strains include: 1)The PSB strains increased the root activity, chlorophyll b, soluble protein, nitrogen, phosphorus and potassium contents in masson pine seedlings; 2)meanwhile, PSBs enhanced the contents of available phosphorus, available potassium, active nitrogen, soil urease and phosphatase in rhizosphere soil; 3)in addition, the addition of three PSB strains also affected the composition and diversity of the rhizosphere bacterial community, and promoted the significant enrichment of beneficial bacteria such as Bacillus, Nitrosospira, Gemmata and Cytophaga in the rhizosphere soil. In conclusion, the three Paraburkholderia spp. strains could promote masson pine seedlings growth by regulating plant physiology and changing rhizosphere micro-environment. This study provides a theoretical basis for the development and application of rhizosphere PSB fertilizer of P. massoniana.

Key words: phosphate-solubilizing bacteria, growth promotion, Paraburkholderia spp., Pinus massoniana