Data from: Herbivory-induced volatiles function as defenses increasing fitness of the native plant Nicotiana attenuata in nature

From an herbivore’s first bite, plants release herbivory-induced plant volatiles (HIPVs) which can attract enemies of herbivores. However, other animals and competing plants can intercept HIPVs for their own use, and it remains unclear whether HIPVs serve as an indirect defense by increasing fitness for the emitting plant. In a two-year field study, HIPV-emitting N. attenuata plants produced twice as many buds and flowers as HIPV-silenced plants, but only when native Geocoris spp. predators reduced herbivore loads (by 50%) on HIPV-emitters. In concert with HIPVs, plants also employ antidigestive trypsin protease inhibitors (TPIs), but TPI-producing plants were not fitter than TPI-silenced plants. TPIs weakened a specialist herbivore’s behavioral evasive responses to simulated Geocoris spp. attack, indicating that TPIs function against specialists by enhancing indirect defense.

从草食动物首次取食植物开始，植株便会释放草食动物诱导植物挥发物（herbivory-induced plant volatiles, HIPVs），此类挥发物可吸引草食动物的天敌。但其他动物以及存在竞争关系的植物可截获HIPVs以供自身利用，目前学界仍不清楚HIPVs是否可通过提升释放植株的适合度，从而发挥间接防御的作用。在一项为期两年的野外研究中，释放HIPVs的渐狭叶烟草（N. attenuata）所产生的芽与花数量，为HIPV沉默植株的两倍，但该现象仅在本地蝽属（Geocoris spp.）天敌使HIPV释放植株上的草食动物负载量降低50%时方才出现。与HIPVs协同发挥作用的还有植物所合成的抗消化性胰蛋白酶蛋白酶抑制剂（trypsin protease inhibitors, TPIs），但表达TPIs的植株其适合度并未高于TPI沉默植株。研究发现，TPIs会削弱专食性草食动物对模拟蝽属天敌攻击的行为躲避反应，这表明TPIs可通过增强间接防御来对抗专食性草食动物。