Rice sheath blight is a destructive fungal disease caused by Rhizoctonia solani. To find a safe and green measure, the biological activity of six plant extracts against R. solani was determined by mycelial growth rate method. The results showed that magnolol possessed better antifungal activities against R. solani, with an EC₅₀ value of 7.47 mg/L. further action mechanism of magnolol against R. solani was carried out. Studies by scanning electron microscopy (SEM) showed that the morphology of R. solani mycelia was deformation and surface folds. Transmission electron microscope (TEM) observation on treated R. solani showed that magnolol could induce cytoplasmic membrane rupture and cytoplasmic membrane even disappeared completely accompanied with cellular debris was covered around this fungal, and the mycelia treated with magnolol showed fluorescence after PI staining. Further study showed that the content of malondialdehyde (MDA) and activity of chitinase, β-1,3-glucanase and relative conductivity of mycelia were increased, while the content of soluble protein and activities of catalase (CAT), polyphenol oxidase (PPO), superoxide dismutase (SOD), succinate dehydrogenase (SDH) and NAD-malate dehydrogenase (NAD-MDH) were significantly decreased. These results indicated that magnolol could significantly damage the plasma membrane of R. solani, and interfere with cell respiratory metabolism, thus inhibiting the growth of mycelium.

水稻纹枯病是由立枯丝核菌引起的一种破坏性真菌病害。为寻找一种安全、绿色的措施，采用菌丝体生长速率法测定了六种植物提取物对茄属植物的生物活性。结果表明，厚朴酚对茄病菌具有较好的抗真菌活性，EC ₅₀值为7.47 mg/L。对厚朴酚对茄病菌的进一步作用机制进行了研究。扫描电镜(SEM)研究表明，茄病菌菌丝体形态为变形和表面褶皱。处理过的茄属植物的透射电子显微镜 (TEM) 观察表明厚朴酚可诱导细胞质膜破裂，细胞质膜甚至完全消失，细胞碎片覆盖在该真菌周围，用厚朴酚处理的菌丝体在 PI 染色后显示荧光。进一步研究表明，丙二醛（MDA）含量及几丁质酶、β-1,3-葡聚糖酶活性及菌丝相对电导率升高，可溶性蛋白含量及过氧化氢酶（CAT）、多酚氧化酶（PPO）活性升高, 超氧化物歧化酶 (SOD)、琥珀酸脱氢酶 (SDH) 和 NAD-苹果酸脱氢酶 (NAD-MDH) 显着降低。这些结果表明厚朴酚可显着破坏R. solani的质膜，并干扰细胞呼吸代谢，从而抑制菌丝体的生长。