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采用光学视频接触角测量仪测定了苹果叶片的表面自由能,以及2.5%高效氟氯氰菊酯水乳剂(beta-cyfluthrin EW)稀释液的表面张力及静态接触角、0~60 s动态接触角。结果表明:苹果叶片近轴面的表面自由能为52.76 m J/m2,以极性分量为主导;而远轴面的表面自由能为21.79 m J/m2,且以色散力分量(非极性分量)为主导。高效氟氯氰菊酯水乳剂2 000倍稀释液的表面张力为52.45 m N/m,与25 g/L高效氟氯氰菊酯乳油3 000倍稀释液的相近,远低于去离子水的表面张力74.65 m N/m;其静态接触角与25 g/L高效氟氯氰菊酯乳油3 000倍稀释液的无显著差异,且在0~60 s内接触角下降趋势最快。研究表明:苹果叶片的近轴面比远轴面更易被药液润湿;在苹果园喷施2.5%高效氟氯氰菊酯水乳剂时,药液的稀释倍数不宜太高,以2 000倍为最佳。
The surface free energy of apple leaves and the surface tension and static contact angle of 2.5% beta-cyfluthrin EW dilution liquid were measured by optical video contact angle measuring instrument. The dynamic contact angle was 0-60 s. The results showed that the surface free energy of the apple leaves was 52.76 m J / m2, which was dominated by the polar component, while the surface free energy of the distal surface was 21.79 m J / m2. The dispersive force (nonpolarity Component) is dominant. The surface tension of the 2 000-fold dilution of the beta-cypermethrin emulsion was 52.45 mN / m, which was close to the 3000-fold dilution of 25 g / L beta-cypermethrin EC, well below the surface tension of the deionized water of 74.65 mN / m. There was no significant difference between the static contact angle and the 3 000-fold dilution of 25 g / L beta-cyfluthrin EC, and the contact angle decreased most rapidly in 0-60 s. The results show that the apple’s leaf is more easily wetted by chemicals than the far-axial surface at the paraxial plane. When the 2.5% beta-cypermethrin emulsion is sprayed in the apple orchard, the dilution ratio of the solution should not be too high, preferably 2 000 times .