21种药用植物提取物对柑橘青霉病抑菌作用的筛选及白薇醇提物对脐橙青霉病的防治效果 Screening of antifungal activity of extracts from 21 species of medicinal plants against Penicillium italicum of citrus fruits and the efficacy of Cynanchum atratum ethanol extracts for control
为开发研制新型植物源柑橘保鲜剂，以抑菌圈直径为指标，利用牛津杯法筛选出对柑橘采后意大利青霉有良好抑制作用的21种中草药的醇提物，并对白薇醇提物防治脐橙青霉病的效果进行了评价。结果表明：白薇、零陵香、鸦胆子、藏青果、白药子5种中草药乙醇提取物对意大利青霉均有较好的抑制效果，抑制圈直径达26 mm以上，其中白薇醇提物抑菌活性最佳，抑制圈直径可达38.39 mm，最小抑菌浓度和最小杀菌浓度分别为3.13 mg/mL和6.25 mg/mL，且抑菌效果与对照药剂1000倍咪鲜胺显著差异。25 mg/mL白薇醇提物处理脐橙7 d后，对脐橙青霉病的防治效果达35.93%，与1000倍咪鲜胺的防治效果相当（36.37%）；白薇醇提物处理后可抑制意大利青霉菌菌丝生长，导致菌丝肿胀、膨大、畸形、细胞膜透性增加、细胞内含物外渗；还可诱导脐橙体内过氧化物酶活性下降，而苯丙氨酸解氨酶和几丁质酶活性上升。表明白薇醇提物对脐橙采后青霉病具有较好的防治效果，可进一步开发为植物源柑橘保鲜剂。 To develop new-style plant-derived preservative for citrus fruits, the antifungal activity of extracts from 21 species of Chinese medicinal herbs against citrus blue mold Penicillium italicum was investigated by cylinder-plate method, and the efficacy of extracts of selected Cynanchum atratum Bunge to control the disease on navel orange was also determined. The results showed that ethanol extracts of C. atratum, Ocimum basilicum L., Brucea javanica(L.) Merr., Terminalia chebula Retz and Stephania cepharantha Hayata efficiently inhibited the growth of P. italicum with inhibition zones all over 26 mm in diameter. Among all the selected medicinal plants, the extract from C. atratum showed the best antifungal activity, of which the inhibition zone diameter, minimum inhibitory concentration and minimum fungicidal concentration were 38.39 mm, 3.13 mg/mL and 6.25 mg/mL, respectively, similar to those of treatment with prochloraz. Likewise, treatments with the extract at 25 mg/mL and prochloraz produced similar efficacies of disease control with 35.93% and 36.37%, respectively. The ethanol extract of C. atratum significantly inhibited the mycelial growth and caused cytoplasm leakage and morphological changes including swollen, curliness and deformity in hyphae of P. italicum. The peroxidase activity of navel orange decreased, while those of phenylalanine ammonia-lyase and chitinase increased upon treatment with the extract. The results indicate that the ethanol extract of C. atratum is effective in blue mold disease control and may be further developed into plant-derived preservative for citrus fruits.