The Study On Seeding Effects Of Spent Mushroom Substrate And Rhizospheric Microbial Community Dynamics On Watermelon And Muskmelon

The spent mushroom substrate is the organic material remaining after the mushroom has been harvested. In the current study, spent mushroom substrates(oyster mushroom and lentinula edodes) were used as the main seedlings substrate of watermelon and muskmelon. The optimum seedling substrate formula was obtained by condition experiments, the correlation between rhizospheric enzyme activity and fertility factors were analyzed, and the rhizospheric microbial community dynamics in seedling growth process was illustrated to evaluate the seeding efficiency of spent mushroom substrate.1.Physicochemical properties of different matrix substrates and biological characters of seedlings were tested, which was revealed that the effect of spent mushroom substrate was overweight that of traditional substrate, e.g. soil and organic fertilizer. The strong seedlings index of watermelon and muskmelon was highest in the substrate(Shiitake mushroom: Oyster mushroom: soil=1:1:2, volume ratio).2.The activity of rhizospheric enzyme(i.e. urease, neutral phosphatase, acid phosphatase and alkaline phosphatase) were detected at the seedling growth process under different matrix substrates. The correlation analysis between enzyme activity and fertility factors of substrate(total nitrogen, total phosphorus, organic matter and pH) showed that, the rhizospheric urease activity was positive correlated to the ground dry weight of seedlings and total nitrogen in terms of watermelon and muskmelon, and the rhizospheric neutral phosphatase activity was positive correlated to the underground dry weight of seedlings and total phosphorus, and the alkaline phosphatase activity in watermelon was positive correlated to the substrate pH, while this correlation was negative in the muskmelon.3. Denaturing Gradient Gel Electrophoresis(DGGE) was used to illustrated the microbial community dynamics in the rhizosphere of seedlings. The Quantity One software was employed to calculate the Shnnon-Weaver and Simpson biodiversity based on DGGE pattern. In the watermelon seedlings, the rhizospheric bacterial diversity(Shnnon-Weaver and richness index) was improved in the process of seedlings growth, and Simpson index was increased as well, which indicated that the abundance of high activity bacteria was boosted and become the predominant. While, Shnnon-Weaver and Simpson index was no significantly changes in the muskmelon seedlings. The recovering and 16 S rDNA sequencing of DGGE Bands demonstrated that Bacillus subtilis, Paenibacillus mucilaginosus and Paenibacillus polymyxa were dominated in spent mushroom substrate, and Clostridium difficile was the predominant in the traditional organic fertilizer substrate.