荧光假单胞菌对采后锦橙青霉病的防治和贮藏品质的影响

Effects of Pseudomonas fluorescens on controlling blue mold caused by Penicillium italicum in Jincheng citrus fruits and its storage quality

以"北碚447"锦橙果实为实验材料,研究了荧光假单胞菌(Pseudomonas fluorescens)对采后锦橙青霉病的防治效果和贮藏品质及感官品质的影响。利用P. fluorescens不同浓度菌悬液和各种处理液分别进行离体和活体实验。离体实验结果表明,1×10~8CFU/mL菌悬液在混合固体培养基上和意大利青霉孢子共同培养时,能完全抑制其生长繁殖,对峙培养时,相对抑菌率高达(52. 59±1. 59)%;在马铃薯葡萄糖液体培养基中意大利青霉孢子12 h后的萌发率和芽管长度分别为(0. 67±0. 47)%和(2. 25±0. 25)μm。活体实验结果表明,P. fluorescens菌悬液抑菌效果最好,且其浓度越高,防治效果越好,浓度为1×10~9CFU/mL时,果实的发病率和病斑直径仅为(49. 17±1. 18)%和(2. 72±0. 09) cm; 4℃下培养16 d,20℃下培养8 d,P. fluorescens在果实伤口处的活菌数分别增长了28倍和34倍;和对照相比,P. fluorescens能显著提高果实几丁质酶和β-1,3-葡聚糖酶的活性,有效增强果实的抗病性;经P. fluorescens菌悬液保鲜的果实,病情指数显著降低,且感官品质和对照差别较小,表明该P. fluorescens试验菌株在锦橙采后病害上具有极高的生物防治潜力。

The present study was conducted to investigate the effects of treatments with Pseudomonas fluorescens on controlling blue mold caused by Penicillium italicum and storage quality and sensory quality of postharvest Jincheng citrus fruits.In vitro and in vivo experiments were carried out by using different concentrations of P.fluorescens suspension and various processing fluids.In vitro results showed that P.fluorescens could completely inhibit the growth of P.italicum when it was incubated with spore suspension of P.italicum in agar plate.The relative inhibition rate was up to(52.59±1.59)%when it was cultured confronting against P.digitatum.The spore germination rate and germ tube length was only(0.67±0.47)%and(2.25±0.25)μm,respectively,when the concentration of bacterial suspension was 1×10 8 CFU/mL.In vivo results showed that the inhibitory effects of P.fluorescens suspension on blue mold on postharvest Jincheng orange was related to the concentration.The higher concentration,the disease incidence would be lower and the lesion diameter would be smaller.When the bacterial suspension was applied at 1.0×10 9 CFU/ml,the disease incidence and lesion diameter was only(49.17±1.18)%and(2.72±0.09)cm,respectively.Moreover,the population of P.fluorescens was increased by approximately 28-and 34-fold after incubation at 20℃for 8 days and 4℃for 16 days,respectively.Furthermore the disease resistance of Jincheng could be enhanced by P.fluorescens through inducing an increase of Chitinase andβ-1,3-glucanase.P.fluorescens could effectively inhibit the disease of fruits,and there was little differences on sensory quality between treatment group with P.fluorescens and control group.Based on the above analysis,the P.fluorescens strain had high biological control potential in the postharvest diseases of Jincheng citrus fruits.