拮抗酵母对西兰花黑斑病及品质的影响

黑斑病是西兰花最常见的采后病害,利用不同浓度拮抗酵母菌悬液可抑制黑斑病,但抑菌效果及对西兰花品质影响尚不清楚。离体试验结果表明,在105~108浓度范围内,随酵母菌悬液浓度增加,黑斑病菌受抑制效果越明显。108 CFU/mL拮抗酵母菌悬液对病原菌菌落生长抑制率最高,为87.9%,对病原菌孢子24 h后的萌发和芽管生长抑制率分别为90.97%,84.05%。活体试验结果表明,西兰花接种105 CFU/mL拮抗酵母菌悬液后,无论是单独存在还是和病原菌同时存在,都能在西兰花伤口处快速繁殖。108CFU/mL拮抗酵母菌悬液处理7 d后西兰花的病斑直径和发病率分别为4.70 mm和21.27%,效果明显好于较低浓度酵母菌处理的西兰花。不同浓度拮抗酵母菌悬液可有效保持西兰花贮藏期间叶绿素、Vc和可溶性糖含量,减缓PPO酶活性升高的趋势,并维持POD酶活性,而108 CFU/mL拮抗酵母菌悬液处理的各项指标优于其他处理组,其保鲜效果最好。因此,拮抗酵母菌可抑制黑斑病菌生长和繁殖,以108 CFU/mL拮抗酵母菌悬液效果为最好,对西兰花PPO酶活性有抑制作用外,对花球其它生理活性无明显影响。

Effects of Antagonistic Yeast on Black Spot Disease and Quality of Post-harvest Broccoli

Black spot is the most common post-harvest disease in broccoli, and it can be inhibited using different concentrations of antagonism yeast suspension, but the effects of antimicrobial activity and the impacts on the quality of broccoli is not clear. The results of in vitro experiments showed that the inhibition effect of black spot increased with the increasing concentrations of yeast within the concentration range of 105~108, .108 CFU/mL yeast suspensions had the highest inhibition rate of pathogenic bacterial colony growth with 87.9%, and the inhibition rate of pathogen spores germination and bud tube length were 90.97% and 84.05% in 24th hour, respectively. The results of in vivo experiments showed that yeast could be very good colonized in broccoli wound whether it was alone or in the presence of the pathogenic bacteria after the broccoli was inoculated with 105 CFU/mL yeast suspensions. The broccoli spot diameter and morbidity were 4.70 mm and 21.27 % in the 7d treated with 108 CFU/mL concentration of yeast suspensions. The effect of 108 CFU/mL of yeast suspensions was significantly better on broccoli than that at lower concentrations of yeast. Different concentrations of antagonism yeasts treatment could effectively maintain the content of chlorophyll, Vc and soluble sugar during storage. Meanwhile, it also decreased the activity of PPO and maintained the activity of POD. Therefore, antagonistic yeasts could inhibit the growth and reproduction of pathogenic bacteria, and the effect of 108 CFU/mL antagonistic yeast suspension was the best. It also decreased the activity of PPO, and there was no significant effect on other physiological quality of broccoli.