苯并噻二唑处理对柑橘果实采后病害控制效果及机制分析

以‘丰脐’柑橘果实为试材，研究了不同浓度苯并噻二唑（benzothiadiazole，BTH）和青霉菌 （Penicillium italicum）、绿霉菌（Penicillium digitatum）、炭疽菌（Colletotrichum gloeosporides）同孔、异孔接 种对柑橘果实青霉病、绿霉病、炭疽病的控制效果，筛选出针对这3 种病害控制效果最适宜的BTH浓度，在此浓 度下考察打孔和浸泡处理对果实果皮内源水杨酸含量和抗病性相关酶活力的影响。实验结果表明：0.25、0.50、 1.00 mmol/L 3 种浓度的BTH与P. italicum、P. digitatum、C. gloeosporioides同孔或异孔接种均可以降低果实青霉病、 绿霉病、炭疽病的病斑直径，其中，0.50 mmol/L的BTH效果最好；在病害发病率方面，3 种浓度的BTH处理均在果 实发病初期有效果，后期效果不显著，相比之下，0.50 mmol/L的BTH效果较好。最适浓度下，通过对果实果皮内源 水杨酸含量和抗病性相关酶活力的研究发现，BTH损伤接种能增加果皮内源水杨酸的含量，BTH浸泡处理对果皮内源 游离态水杨酸含量无显著影响，但能促进果皮内源结合态水杨酸含量的积累；BTH损伤接种和浸泡处理均能增加柑橘 果皮β-1,3葡聚糖酶、几丁质酶、苯丙氨酸解氨酶、过氧化物酶和多酚氧化酶的活力。由此推测，BTH处理诱导柑橘果 实提高了其采后抗病性。

Control and Mechanism of Postharvest Diseases in Citrus Fruits by Benzothiadiazole Treatment

(Fengqi Navel) orange fruits (Citrus sinensis L. Osbeck) were used as experimental subjects to evaluate the efficacy of different concentrations of benzothiadiazole (BTH) in controlling lesion diameters and disease incidence in citrus fruits inoculated with Penicillium italicum, Penicillium digitatum and Colletotrichum gloeosporides separately in the same and different wounds. At the same time, the optimum concentration of BTH to control these diseases was determined. The effects of BTH wound inoculation and dipping treatment on endogenous salicylic acid (SA) content and disease resistance-related enzymes activities in citrus peel were also investigated. The results indicated that BTH treatment at three concentrations (0.25, 0.50, 1.00 mmol/L) could reduce lesion diameters of citrus fruits inoculated with three pathogens and the best effect was observed at 0.50 mmol/L. All these three treatments controlled disease incidence at the early stage of disease, but the effect was marginal at the late stage. By comparison, BTH at 0.50 mmol/L was most effective. BTH wound inoculation at the optimum concentration could increase the content of endogenous SA in the peel. BTH dipping treatment had no significant effect on the content of endogenous free SA in the peel, but could promote the accumulation of endogenous bound SA content. Both BTH treatments could increase the activities of β-1,3-glucanase (GLU), chitinase (CHI), phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) in the peel. Therefore, BTH could be effective in inducing postharvest disease resistance in citrus fruits.