3种药用作物对烟草黑胫病菌的抑菌效果研究

Antifungal effects of three medicinal crops on Phytophthora nicotianae

烟草黑胫病是由疫霉菌侵染引起的最具危害的土传病害之一,为寻找该病的控制方法,该试验采用菌丝生长速率法,研究了玄参、川明参、半夏等作物茎叶根系提取物、根系分泌物以及提取物与分泌物组合对烟草黑胫病的抑菌效果,结果表明:(1)玄参、川明参、半夏的茎叶和根系提取物对烟草黑胫病菌有不同程度的抑制作用,且随提取物浓度增大而增强;其中,玄参抑菌活性最强,0.5 g·mL^(-1)时茎叶、根系提取物抑菌率分别达74.88%,69.27%;川明参与半夏抑制效果相对较差;川明参茎叶和根系提取物组合后,有明显增益效应。(2)玄参、川明参、半夏根系分泌物对烟草黑胫病菌均表现出一定的抑菌性,随浓度增大而增强;抑菌强度为川明参>玄参>半夏。(3)提取物与根系分泌物组合的抑菌性,玄参、川明参相近而强于半夏,均介于各自提取物与根系分泌物之间。玄参、川明参具有防控烟草黑胫病的应用潜力。

Tobacco black shank is one of the most harmful soil-borne diseases infected by Phytophthora parasitica. In order to probe the control method to this disease, in this study, the mycelial growth rate method was employed to investigate the antifungal effects of extracts from stem-leaf and root, root exudates, and their combination of Scrophularia ningpoensis, Chuanmingshen violaceum and Pinellia ternata The results showed that：①Stem-leaf and root extracts of S. ningpoensis, C. violaceum and P. ternata exhibited different antifungal activities, and the inhibition increased with the increase of extract concentration. The antifungal effect of S. ningpoensis extracts at 0.5 g·mL-1 was the strongest than other medicinal plants, the inhibition rate of steam-leaf and root extracts reached 74.88%, 69.27%, respectively. The inhibitory effect of C. violaceum and P. ternata was relatively lower, however, there is a significant gain effect after combination of steam-leaf and root extracts of C. violaceum. ②The root exudates of S. ningpoensis, C. violaceum and P. ternata showed fungistasis to Phytophthora nicotianae, and fungistasis was enhanced with the increase of root exudate concentration. The antifungal effect in the order of C. violaceum 〉 S. ningpoensis 〉 P. ternata. ③The antifungal activity of combination of extract and root exudate from S. ningpoensis was similar with the effect of C. violaceum, they were both stronger than P. ternata, and the antifungal activity for three combination were located between the antifungal activity of their extracts and root exudates. S. ningpoensis and C. violaceum can be potentially applied to prevent and control the tobacco black shank.