1. Chlorine dioxide is a safe and efficient oxidative disinfectant, which has been widely used in food production, drinking water, medical equipment, indoor pollution, public health and other aspects of disinfection and sterilization in many countries. Some studies at home and abroad have shown that Chlorine dioxide at an appropriate concentration can damage the cell walls and cell membranes of fungal spores and affect the number of pathogenic bacteria such as Botrytis cinerea, Cladosporium, Trichoderma, Penicillium, Escherichia coli, Salmonella typhimurium and Listeria It has a very good inhibitory effect, and the growth of plants cultivated on Chlorine dioxide sterilized medium is similar to or better than that of autoclaved medium. At present, there are few reports on the study of Chlorine dioxide on Streptomyces.

2. Grapes are one of the unstorable fruits with thin skins and soft flesh. They are easily infected by pathogenic microorganisms after harvest, which causes huge economic losses. Among them, Alternaria rot is one of the most prominent post-harvest diseases of grape fruits. The main pathogenic bacteria is Alternaria spp. It has strong adaptability to the ecological environment and rapid growth and reproduction, which seriously affects the host’s plasma membrane permeability. Sex, enzyme activity, hormone balance and other physiological metabolic processes, which cause a lot of fruit rot. Recently, some researchers used different concentrations of Chlorine dioxide to treat Alternaria spp. and living Alternaria spp. for different times to explore the effect of Chlorine dioxide on Alternaria spp., and provide theoretical basis for the application of Chlorine dioxide in grape storage and preservation.

3. The results of the study were compared with the control group. The treatments with various concentrations of Chlorine dioxide inhibited the growth of Alternaria hyphae to varying degrees, and with the increase of Chlorine dioxide concentration and the extension of time, it inhibited the growth of Alternaria hyphae The effect is also gradually enhanced. Among them, the inhibition rate of the 9.0 μg/L Chlorine dioxide treatment group is significantly higher than that of the other groups. The culture dish treated at this concentration for 30 min still has no hyphae growth on the 6th day, which can indicate that Chlorine dioxide will reduce Alternaria alternata. Almost all of the spores were killed.

4. The inhibition rate of germ tube elongation is a parameter to measure the influence of Chlorine dioxide on the growth of Alternaria alternata. The inhibition rate of the control group is 0. The closer the inhibition rate is to 100%, the better the inhibition effect. The figure below shows that treatments with different concentrations of ClO2 have different degrees of inhibition on the elongation of Alternaria sp. germ tubes. With the increase of Chlorine dioxide concentration and time, the inhibition rate of shoot tube elongation basically showed an upward trend. When the concentration reached 9 μg/L, the treatment time was longer than 20 min to achieve the full inhibition effect. The researchers also studied the effect of Chlorine dioxide on the germination of Alternaria spores, and the results were similar to the inhibitory effect of germ tube elongation.

5. As shown in the figure below, compared with the control group, the density of the hyphae of Alternaria spp. cultured by Chlorine dioxide treatment decreased significantly, and the hyphae surface was rough and gully appeared. Observed under a high-power microscope, the internal cytoplasm of Alternaria spp. hyphae agglomerated, and the hypha became hollow, darkened, thickened, and shrunken. When treated with 9.0 μg/L Chlorine dioxide for 30 minutes, no hyphae grew during the entire culture period. . On the other hand, the hyphae of the control group were quite dense, with many spores growing between the hyphae, and the hyphae at the edges were smooth and tightly surrounded. This shows that ClO2 has a certain inactivation effect on the spores of Alternaria spp., which can damage the hyphae, and high concentrations may cause the hyphae to break.

6. The above studies show that Chlorine dioxide can effectively inhibit the hypha growth, germ tube elongation and spore germination of Alternaria alternata in vitro, and cause damage to the hyphae of Alternaria alternata. The greater the Chlorine dioxide concentration, the longer the treatment time, and the better the inhibitory effect. When the spore concentration of Alternaria spp. is 1×106/mL, 9.0 μg/L Chlorine dioxide treatment for 30 min can completely inhibit spore germination. At the same time, the grape berries after CIO2 airtight fumigation inoculation can effectively maintain high PPO, POD and SOD activities during storage, and their better antioxidant properties can effectively slow down the damage of free radicals in the fruit to cell membranes, and resist and block free oxygen. The damage caused by the base to the fruit cells can repair the damaged cells in time and enhance the ability of the fruit to resist the infection of Alternaria sp.