侧柏挥发性化学成分的鉴定及其对双条杉天牛的触角电位反应

行为试验发现侧柏饵木对双条杉天牛有很强的引诱作用。采用顶空吸附采样方法林间采集侧柏不同部位的挥发性成分,经热脱附吹扫捕集-气相色谱-质谱联用分析,发现侧柏释放的挥发性成分主要由脂肪族的绿叶成分和单萜烯组成。固相微萃取和水蒸汽蒸馏采集侧柏韧皮成分,分析发现其主要成分由单萜烯、倍半萜烯及其衍生物组成,两种采样方法的采样效果有一定的差异。触角电位研究表明,双条杉天牛触角对挥发性绿叶成分正戊醇、正己醇、2-乙基-1-己醇和1-辛烯-3-醇有很强的触角电位反应;对醛类化合物触角电位反应较弱;对单萜烯类化合物香桧烯、侧柏醇和(-)-柠檬烯有很强的触角电位反应。双条杉天牛对小蠹虫的信息素都有很强的触角电位反应,特别是对3-甲基-2-环己烯-1-醇及其酮类化合物。含6个碳或8个碳的醇类成分与马鞭草烯酮结合和侧柏挥发性的单萜烯类成分对双条杉天牛寻找寄主的行为可能有很大影响。

Analysis of Platycladus orientalis Volatiles and Their Electroantennogram Responses with Semanotus bifasciatus

Behavioral tests revealed that Semanotus bifasciatus was easy to be attracted to its host trees species, Platycladus orientalis. The volatiles emitted from different parts of P. orientalis were collected outdoors by headspace sampling in situ and analyzed by Thermodesorption Cold Trap (TCT)-GC-MS. Two major classes of compounds, aliphatics [mainly green-leaf volatiles (GLVs)] and monoterpenes, existed in the host tree species investigated. Sesquiterpenes and monoterpenes (and their derivatives) sampled from the phloem by the solid phase microextraction (SPME) and hydrodistillation made up the major part of whole volatile blends. However, differences could be found with respect to a few components of the blend. Electroantennograms from the antennae of S. bifasciatus were recorded in response to compounds presented in the headspace of P. orientalis and other sources. The antennae responded strongly to green leaf alcohols: 1-Pentanol, Hexanol, 2-ethyl-1-Hexanol and 1-Octen-3-ol; but a little EAG amplitudes were observed to aldehydes; Better antennal responses to Sabinene, Thujanol and (-)-Limonene were found. In addition, the antennae were more sensitive to that of bark beetle pheromones than some monoterpenes and alcohols, especially the compounds 3-methyl-2-cyclohexen-1-ol and 3-methyl-2-cyclohexen-1-one. The blends of C6 and C8 alcohols plus verbenone together with monoterpenes might play an important role in host selection of S. bifasciatus.