Aphids are considered one of the most damaging pests in agriculture. Plants respond to aphid attack with the production of toxic, repellent and/or antinutritive metabolites, including phenolic compounds. In this study, we examined the free phenolic acid composition of pepper (Capsicum annuum L.) leaves in response to green peach aphid (Myzus persicae Sulzer) feeding in different time course experiments. When plants were infested with an initial low density of aphids (20 aphids/plant), few significant changes were shown in leave phenolic content suggesting a very slight response from plants. However, with a high density of aphids (200 aphids/plant), several phenolics, especially the cinnamic acids (C6-C3): caffeic acid, p-coumaric acid, and sinapic acid, and also the p-hydroxybenzoic acid, salicylic acid, accumulated at specific times. Conversely, another hydroxy-benzoic acid: protocatechuic acid strongly decreased in response to infestation. The possible role of the observed changes in plant defence responses or in aphid counter-defence is discussed.

蚜虫被认为是农业中最具破坏性的害虫之一。植物通过产生毒性，驱避性和/或抗营养性代谢产物（包括酚类化合物）来应对蚜虫侵袭。在这项研究中，我们研究了辣椒（Capsicum annuum L.）叶片在不同时程实验中响应绿桃蚜（Myzus persicae Sulzer）进食后的游离酚酸成分。当植物受到最初低密度的蚜虫侵染（每株植物有20个蚜虫）时，叶子中的酚含量几乎没有显着变化，表明植物的响应非常微弱。但是，由于蚜虫的密度很高（每株植物有200个蚜虫），所以有几种酚类，尤其是肉桂酸（C6-C3）：咖啡酸，p-香豆酸和芥子酸，以及对羟基苯甲酸，水杨酸在特定时间积累。相反，另一种羟基苯甲酸：原儿茶酸则由于侵染而大大降低。讨论了观察到的变化在植物防御反应或蚜虫防御中的可能作用。