不同品种黄瓜对B型烟粉虱羧酸酯酶活性的影响

采用酶标仪动力学法,比较研究了3个黄瓜品种对B型烟粉虱Bemisia tabaci(Gennadius)羧酸酯酶比活力的影响。结果表明,不同品种黄瓜对B型烟粉虱羧酸酯酶活性具有明显的影响:取食四季秋瓜和22-94RZ的B型烟粉虱羧酸酯酶活性均较高,其比活力最低值分别为对照的1.07倍和1.27倍;取食Deltastar RZ的为最低,其羧酸酯酶比活力最低值仅为对照的0.56倍。取食不同品种黄瓜不同时间,B型烟粉虱羧酸酯酶比活力动态变化趋势不同:取食四季秋瓜、22-94RZ的B型烟粉虱,其羧酸酯酶比活力始终保持被激活状态;取食Deltastar RZ后则处于被抑制状态,但72h后恢复至起始水平,说明B型烟粉虱在Deltastar RZ上具有较强的恢复能力,适应性较好。研究表明羧酸酯酶在B型烟粉虱选择适应寄主过程中应该起着重要作用。

Effects of different cucumber varieties on carboxylesterase activity in Bemisia tabaci B-biotype

The effect of different varieties of cucumber on the carboxylesterase （CarE） activity of the B-biotype of the tobacco whitefly,Bemisia tabaci （Gennadius） was studied in order to provide basic information for developing new varieties of insect-resistant cucumber and improve the integrated management of this pest.Using the kinetic method,differences in CarE activity of tobacco whiteflies fed on the leaves of three different cucumber varieties was analyzed at T=23—27℃ and RH=80%±5% in a laboratory.The CarE activity of tobacco whiteflies varied significantly with cucumber variety.The lowest specific CarE activity was measured in whiteflies fed on Sijiqiugua or 22-94 RZ cucumbers which was 1.07 or 1.27 times higher,respectively,than the control,and 0.56 times lower than that of whiteflies fed on Deltastar RZ cucumbers.There was a significant difference in the dynamics of CarE activity between whiteflies fed on Sijiqiugua or 22-94 RZ and those fed on Deltastar RZ.CarE activity in whiteflies fed on both Sijiqiugua and 22-94 RZ cucumbers generally increased during the experiment,whereas that of whiteflies fed on Deltastar RZ cucumbers decreased after 3 to 24 hours,increased after 48 hours and finally returned to its original level after 72 hours.This demonstrates that whiteflies were able to control CarE activity when feeding on Deltastar RZ cucumbers.These results indicate that CarE may be important in host plant selection by the B.tabaci B-biotype.