JIA-2018-09

2027 Tamaki Masahiko et al. Journal of Integrative Agriculture 2018, 17(9): 2024–2030 nontreatment (Fig. 3-A), the treatment with FB solution only (Fig. 3-B) and containing CO 2 MMB (Fig. 3-C) show that some conidia had lipid granules lining up along the lines inside the membrane and the septum; however, the conidia treated with FB solution containing both CO 2 MBs (Fig. 3-D and E) showed bloated or no lipid granules and an expansion of the vacuole and the intracellular space. Furthermore, intracellular space site of the conidium treated with BF solution containing the decompression-type CO 2 MB were damaged worse than the gas-water circulating-type CO 2 MB. 4. Discussion According to Takahashi (2005), MB has the larger specific surface area and the slower ascend rate than MMB, resulting in higher gas dissolution efficiency. In the present study, the dissolved CO 2 concentration in both CO 2 MBs was higher than that in CO 2 MMB because the pH of the BF solution treated with both CO 2 MBs was lower than that with CO 2 MMB. A previous study has shown that the inactivation of Bacillus cereue spores by heat treatment can be promoted by dissolved CO 2 and decreased pH, which can be achieved with the addition of CO 2 (Kim et al . 2012). Takagi (2006) also stated that MB led to a drastic decrease in the ascend rate and to coalescence inhibition and sterilization over a prolonged period in the presence of surfactants. In addition, the MB size decreases in the presence of surfactants (Fujioka et al . 2012), while physical absorption and matter transport capacity increase in the characteristic gas-liquid interface of MB (Li et al . 2009). Therefore, we consider Fig. 1 Inhibition of germination and appressorium formation of Pyricularia oryzae Cavara conidia by Blasin ® Flowable (BF) solution containing carbon dioxide millibubbles (CO 2 MMB) and both CO 2 microbubbles (CO 2 MBs). Treatment with BF solution was performed for 5 min. A, germination ratio. B, appressorium formation ratio. Different uppercase and lowercase letters indicate significant differences among the BF concentration of the same treatments and different treatments at the same concentration of BF by Tukey-Kramer method, respectively ( P <0.01). Data are means±SE ( n =6). 0 20 40 60 80 100 No addition 50 000 10 000 5 000 1 000 Nontreatment CO 2 MMB The gas-water circulating-type CO 2 MB The decompression-type CO 2 MB 0 20 40 60 80 No addition 50 000 10 000 5 000 1 000 Dilution ratio of BF solution Dilution ratio of BF solution Germination ratio (%) Appressorium formation ratio (%) A B C a B a B a B a BC a B a B a B a C a B a BC a C a C a B a C a C a B a A a A a AB a A a A a A a BC b B b B b B b A b B b B b A b A ab A a A a A a A a A a A a A a A a