假臭草和九里香甲醇提取液对橡胶树白粉病菌抑菌活性的测定

为筛选防治橡胶树白粉病安全有效的植物源杀菌剂,采用孢子萌发抑制法测定22种植物甲醇提取液对橡胶树白粉病菌孢子的抑菌活性.结果表明,假臭草和九里香提取液浓度在0.1 g/mL时,对橡胶树白粉病菌孢子的萌发抑制率分别为43.98％和47.62％,极显著优于其它植物和对照.进一步测定假臭草和九里香提取液的EC50和EC75值,以及其盆栽试验的防治效果与橡胶树叶片丙二醛(MDA)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和苯丙氨酸解氨酶(PAL)的活性.结果表明,假臭草和九里香对病原菌孢子的EG50值分别为0.26 g/mL和0.20 g/mL,EC75值分别为1.12 g/mL和0.99 g/mL.假臭草和九里香提取液浓度在EC75值时,防病效果分别为20.00％和18.67％,显著高于对照.假臭草和九里香提取液处理后,橡胶树叶片的MDA含量极显著低于对照,CAT、SOD和PAL活性则显著或极显著高于对照.由此可见,假臭草和九里香提取液不仅能抑制病原菌的萌发和生长,而且能提高橡胶树的抗病性.

The Bioassay of Methanol Extracts from Eupatorium catarium and Murraya paniculata on Inhibition of Oidium heveae

Rubber tree powdery mildew disease, caused by Oidium heveae, is one of the significant leaf diseases in rubber trees. To find the botanical fungicide that could effectively control the disease, the spore germinating inhibition method was used to determine the effect of methanol extracts from 22 plant species on antifungal activity in this test. The results showed that extracts from Eupatorium catarium and Murraya paniculata in a concentration of 0.1 g/mL inhibited the germination of the spore by 43.98% and 47.62%, respectively, which were significantly more effective than those from other plants and the control. The EC50 and EC75 of methanol extracts from E. catarium and M. paniculata had control effect on potted plant materials and the activities of MDA, CAT, SOD, and PAL in rubber leaves after controlling the disease were further measured. The results showed that the EC50 of extracts from E. catarium and M. paniculata was 0.26 g/mL and 0.20 g/mL, respectively, and the EC75 1.12 g/mL and 0.99 g/mL, respectively. The control effects in pot experiment of the extracts from E. catarium and M. paniculata in the concentration of EC75 was 20.00% and 18.67%, respectively, significantly higher than that of the control. After treatment with the extracts from E. catarium and M. paniculata, the MAD content in leaves was significantly lower, while the CAT, SOD, PAL contents were higher than the control. These results suggested that the methanol extracts from E. catarium and M. paniculata could not only inhibit the germination and growth of the pathogen, but also elevate the host disease resistance.