Effects Of H₂S On Post-harvest Diseases And Storage Of Dangshan Pear

The fresh-keeping method of Dangshan Pear is always the key point for fuitfresh keeping. Strains were isolated from the rotten Dangshan pear and theinfection effects of these microorganisms were investigated. The conditions ofhydrogen sulfide and B.subtilis on the preservation of Dangshan pear were alsostudied in this study.In this thesis, the research contents were as follows：1. Isolation and characterization of pathogenic organism in postharvest rottenDangshan PearAmong the isolated pathogens, M2, M9, M10, M4had strong infection abilityamong mould, and bacteria had little infection ability. In the mixed infectionprocess, strain M2、M9、M10were the key pathogens, which could enhance theability of other pathogenic microorganism infection significantly. The optimumgrowth temperature of strain M2、M9、M10was25℃、30℃、30℃, respectively.And the optimum growth pH of strain M2、M9、M10pH was6、8、4. Meanwhile,M2, M9and M10were capable of produce a large quantity of pectinase andcellulose.2. Effects of hydrogen sulfide on Dangshan pear preservationWhen the concentrations of NaHS were more than2.0mmol/L, the decay ofDangshan pear caused by strains of M2, M9, M10were put off and the growth rateof the pathogenic organism was decreased greatly. The optimum NAHS fumigationconditions were as following: fumigation time was36h and NAHS concentrationwas2.0mmol/L.3. Inhibition effect of Bacillus subtilis on Aspergillus niger M10In the experiment of Bacillus subtilis prevented Aspergillus niger M10, theefficacy of Bacillus subtilis in controlling of M10was very obviously and theantagonism of B.subtilis and M10were very clear.