Abstract:
Objective It is of great significance to isolate and screen salt-tolerant phosphate fungi for improving low-yield saline-alkali soil.
Method Fifteen phosphate-dissolving fungi were isolated from the rhizosphere soil of halophytes and crops in the Yellow River Delta using the transparent circle method. PDA medium containing different NaCl concentrations were used to determine the salt tolerance of the fungi. Liquid culture experiment were used to determine the ability of dissolving Ca3 (PO4)2. F2 (No. of isolated fungi) can tolerate salt concentration up to 7% and F19 can tolerate salt concentration up to 9%. The two phosphate-solubilizing fungi had excellent capability in dissolving phosphorus. In the PVK liquid medium, the highest available phosphorus contents were 480.96 mg/L and 772.69 mg/L, which were 120 and 193 times of the control groups.
Result Based on morphological characteristics and ITS rDNA sequence analysis, F2 and F19 fungal strains were identified as Penicillium oxalicum and Aspergillus niger. On this basis, soil culture and pot experiment were used to test the phosphorus solubilization and growth-promoting effects of the microbial agents. The results showed that the application of microbial agents could significantly increase the level of available phosphorus in saline-alkali soil and promote wheat growth. Compared with the control, the available phosphorus content increased by 38.9% after 15 days of inoculation with F2, and 32.7% after 20 days of inoculation with F19. The average root length of wheat seedlings increased by 37.81% and 38.27%. The average plant height increased by 60.75% and 61.17%.
Conclusion The research results showed that the strains F2 and F19 could be used for the development of phosphorus-dissolving biological fertilizers in saline-alkali soils.
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