Bulgarian Academy of Sciences, Institute of Plant Physiology, Acad. G. Bonchev Str., Bl. 21, Sofia 1113, Bulgaria.
J Chem Ecol. 2010 Jun;36(6):629-41. doi: 10.1007/s10886-010-9801-7. Epub 2010 May 21.
Feeding by herbivorous insects may change photosynthetic activity of host plants. We studied how feeding and oviposition by herbivorous stink bugs, Murgantia histrionica and Nezara viridula (Heteroptera: Pentatomidae), affect photosynthetic parameters of Brassica oleracea (savoy cabbage) and Phaseolus vulgaris (French bean). First, we measured photosynthetic gas exchange, chlorophyll fluorescence imaging, and emission of induced volatile organic compounds (VOC) immediately after feeding and during a post-feeding period. Photosynthesis decreased rapidly and substantially in B. oleracea and P. vulgaris infested by feeding bugs. Stomatal conductance did not decrease proportionally with photosynthesis; instead, inhibition of photosynthesis likely was due to a reduced diffusion of CO(2) in the mesophyll. We also measured the impact of oviposition per se and oviposition associated with feeding on photosynthetic parameters. A surprisingly large inhibition of photosynthesis was detected in cabbage leaves in response to oviposition by M. histrionica, even when oviposition was not associated with feeding activity. High resolution chlorophyll fluorescence imaging revealed that the damage to photochemistry caused by feeding and oviposition was restricted to the attacked areas. By contrast, the photochemical yield increased temporarily in the unaffected areas of the attacked leaves, indicating the onset of a compensatory response. Measurement of volatile organic compounds (VOC) revealed that feeding-damaged plants did not emit detectable amounts of VOC, indicating cellular damage (methanol and green leaf volatiles). However, feeding by M. histrionica induced emission of mono- and sesquiterpenes in savoy cabbage leaves. The different time-course of the induction of these two classes of terpenes may reflect the induction of two different biosynthetic pathways and indicate different roles of these terpenoids in tritrophic interactions.
取食行为可能会改变宿主植物的光合作用。我们研究了植食性臭蝽，Murgantia histrionica 和 Nezara viridula（半翅目：蝽科）的取食和产卵行为如何影响甘蓝和菜豆的光合作用参数。首先，我们在取食后立即和取食后一段时间测量了光合作用气体交换、叶绿素荧光成像和诱导挥发性有机化合物（VOC）的排放。受取食昆虫侵害的甘蓝和菜豆的光合作用迅速且大幅下降。受侵害的 B.oleracea 和 P. vulgaris 的气孔导度并没有与光合作用成比例下降；相反，光合作用的抑制可能是由于叶片间层 CO2 扩散减少所致。我们还测量了产卵本身以及与取食相关的产卵对光合作用参数的影响。令人惊讶的是，即使在与取食活动无关的情况下，M. histrionica 的产卵也会导致甘蓝叶片的光合作用受到很大抑制。高分辨率叶绿素荧光成像显示，取食和产卵对光化学造成的损害仅限于受侵害区域。相比之下，受侵害叶片的未受影响区域的光化学产量暂时增加，表明出现了补偿反应。挥发性有机化合物（VOC）的测量显示，受损植物不会排放可检测量的 VOC，表明细胞受损（甲醇和绿叶挥发物）。然而，M. histrionica 的取食诱导了羽扇豆烷和单萜烯在甘蓝叶片中的释放。这两类萜烯诱导的不同时间进程可能反映了两种不同生物合成途径的诱导，并表明这些萜类化合物在三营养级相互作用中具有不同的作用。
