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研究茉莉酸甲酯(MeJA)和日本龟蜡蚧诱导柿树挥发物对天敌昆虫红点唇瓢虫的吸引作用。结果显示:7月份当日本龟蜡蚧处于若虫阶段时,它的危害并不能诱导柿树对瓢虫的吸引;相反,用茉莉酸甲酯处理过的柿树表现出对瓢虫明显的吸引,呈现升高—降低—再升高的波动变化。在MeJA处理后的8h(当天15:00)和24h(第2天早7:00)达到高峰期,其对瓢虫的吸引率分别为78.21%和73.42%。通过GC/MS分析,从MeJA处理的柿树和对照中共检出4类17种化学成分。2[10]-蒎烯和柠檬油精是在处理柿树中新增加的成分。另外3种萜类化合物的相对含量增加,其中α-蒎烯最为明显。这些挥发物组成的变化揭示了柿树吸引瓢虫的原因。根据对化学成分的分析,选择单组分柠檬油精和α-蒎烯来验证它们对红点唇瓢虫的吸引力。结果证明,两者对该瓢虫都有明显吸引力,在浓度为1×10-4和1×10-5g.mL-1时的吸引率分别为78.95%和75.61%。因此认为,MeJA可以作为一种信号转导分子用于诱导寄主植物释放挥发物,提高对蚧虫的生物防治效果。此外,发现萜类化合物在一天中的波动变化。直到MeJA处理后的8h,6种萜类物质的含量都增加,但到了12h,只检出α-蒎烯其含量为0.87%。然而到第2天早上7:00,所有6种萜类化合物又都重新检测到,其中α-蒎烯甚至达到了73.01%。
To investigate the attraction of persimmon volatiles to the natural enemies of red spot ladybugs, Ladybug, MeJA and Japanese turtle scale. The results showed that when the Japanese turtle scale was in the nymphal stage in July, its harm could not induce the persimmon to attract ladybugs. On the contrary, the persimmon tree treated with methyl jasmonate showed obvious attraction to ladybugs, Showing the rise - decrease - then increase the volatility. At the peak of 8h (15:00) and 24 h (7:00 of the next day) after MeJA treatment, the rates of attraction to ladybugs were 78.21% and 73.42%, respectively. By GC / MS analysis, four classes of 17 chemical constituents were detected from the persimmons treated with MeJA and the control. 2 [10] - Pinene and limonene are newly added ingredients in the treatment of persimmon. The other three terpenoids increased the relative content, of which α-pinene the most obvious. The changes in the composition of these volatiles reveal why persimmon attracts ladybugs. Based on the analysis of the chemical composition, one-component lemon olein and α-pinene were selected to verify their attractiveness to Ladybug. The results show that both have obvious attractiveness to the ladybug, and the attraction rates are 78.95% and 75.61% respectively when the concentration is 1 × 10-4 and 1 × 10-5g.mL-1. Therefore, MeJA can be used as a signal transduction molecule to induce host plants to release volatile compounds and improve the biological control effect of scale insects. In addition, changes in terpenoids were found during the day. Up to 8 h after MeJA treatment, the content of all six terpenoids increased, but only 12.7% of α-pinene was detected by 12 h. However, by 7:00 AM on the second day, all six terpenoids were detected again, with α-pinene reaching even 73.01%.