Ionicon Analytik GmbH, Technikerstrasse 21a, 6020 Innsbruck, Austria.
Physiol Plant. 2010 Feb;138(2):123-33. doi: 10.1111/j.1399-3054.2009.01322.x. Epub 2009 Nov 9.
When plants are damaged by herbivorous insects they emit a blend of volatile organic compounds (VOCs) which include a range or terpenoids and green leaf volatiles (GLVs) formed via different metabolic pathways. The precise timing of these emissions upon the onset of herbivore feeding has not been fully elucidated, and the information that is available has been mainly obtained through laboratory based studies. We investigated emissions of VOCs from Populus tremula L. xP. tremuloides Michx. during the first 20 h of feeding by Epirrita autumnata (autumnal moth) larvae in a field site. The study was conducted using Proton Transfer Reaction-Mass Spectrometry (PTR-MS) to measure emissions online, with samples collected for subsequent analysis by complementary gas chromatography-mass spectrometry for purposes of compound identification. GLV emission peaks occurred sporadically from the outset, indicating herbivore activity, while terpene emissions were induced within 16 h. We present data detailing the patterns of monoterpene (MT), GLV and sesquiterpene (SQT) emissions during the early stages of herbivore feeding showing diurnal MT and SQT emission that is correlated more with temperature than light. Peculiarities in the timing of SQT emissions prompted us to conduct a thorough characterization of the equipment used to collect VOCs and thus corroborate the accuracy of results. A laboratory based analysis of the throughput of known GLV, MT and SQT standards at different temperatures was made with PTR-MS. Enclosure temperatures of 12, 20 and 25 degrees C had little influence on the response time for dynamic measurements of a GLV or MT. However, there was a clear effect on SQT measurements. Elucidation of emission patterns in real-time is dependent upon the dynamics of cuvettes at different temperatures.
当植物受到草食性昆虫的损害时，它们会释放出混合的挥发性有机化合物（VOCs），其中包括一系列萜类化合物和通过不同代谢途径形成的绿叶挥发物（GLVs）。这些排放物在草食性昆虫取食时的确切时间尚未完全阐明，现有的信息主要是通过实验室研究获得的。我们在野外地点调查了 Epirrita autumnata（秋尺蠖）幼虫取食期间白杨杂种（Populus tremula L. x P. tremuloides Michx.）的 VOC 排放情况，使用质子转移反应质谱法（PTR-MS）在线测量排放物，收集样本以进行气相色谱-质谱联用分析，用于化合物鉴定。GLV 排放峰从一开始就零星出现，表明存在食草动物的活动，而萜烯排放则在 16 小时内被诱导。我们提供了详细的数据，说明了在草食性昆虫取食的早期阶段，单萜（MT）、GLV 和倍半萜（SQT）排放的模式，显示出与温度而非光照相关的昼夜 MT 和 SQT 排放。SQT 排放时间的特殊性促使我们对用于收集 VOC 的设备进行了全面的特性描述，从而证实了结果的准确性。通过 PTR-MS 对不同温度下已知 GLV、MT 和 SQT 标准的吞吐量进行了基于实验室的分析。在 12、20 和 25 摄氏度的封闭温度下，对 GLV 或 MT 的动态测量的响应时间几乎没有影响。然而，对 SQT 测量有明显的影响。实时阐明排放模式取决于不同温度下比色皿的动态特性。
