Pincebourde Sylvain, Frak Ela, Sinoquet Hervé, Regnard Jean Luc, Casas Jérôme
Institut de Recherche sur la Biologie de l'Insecte (IRBI, CNRS UMR 6035), Université François Rabelais, Faculté des Sciences et Techniques, 37200 Tours, France.
Plant Cell Environ. 2006 Dec;29(12):2238-47. doi: 10.1111/j.1365-3040.2006.01598.x.
Herbivory alters plant gas exchange but the effects depend on the type of leaf damage. In contrast to ectophagous insects, leaf miners, by living inside the leaf tissues, do not affect the integrity of the leaf surface. Thus, the effect of leaf miners on CO2 uptake and water-use efficiency by leaves remains unclear. We explored the impacts of the leaf-mining moth Phyllonorycter blancardella (Lepidoptera: Gracillariidae) on light responses of the apple leaf gas exchanges to determine the balance between the negative effects of reduced photosynthesis and potential positive impacts of increased water-use efficiency (WUE). Gas exchange in intact and mined leaf tissues was measured using an infrared gas analyser. The maximal assimilation rate was slightly reduced but the light response of net photosynthesis was not affected in mined leaf tissues. The transpiration rate was far more affected than the assimilation rate in the mine integument as a result of stomatal closure from moderate to high irradiance level. The WUE was about 200% higher in the mined leaf tissues than in intact leaf portions. Our results illustrate a novel mechanism by which plants might minimize losses from herbivore attacks; via trade-offs between the negative impacts on photosynthesis and the positive effects of increased WUE.
食草作用会改变植物的气体交换，但影响取决于叶片损伤的类型。与外食性昆虫不同，潜叶虫生活在叶片组织内部，不会影响叶片表面的完整性。因此，潜叶虫对叶片二氧化碳吸收和水分利用效率的影响仍不清楚。我们探究了潜叶蛾Phyllonorycter blancardella（鳞翅目：细蛾科）对苹果叶片气体交换光响应的影响，以确定光合作用降低的负面影响与水分利用效率（WUE）提高的潜在积极影响之间的平衡。使用红外气体分析仪测量完整叶片组织和有潜道叶片组织中的气体交换。在有潜道的叶片组织中，最大同化率略有降低，但净光合作用的光响应未受影响。由于从适度到高辐照水平时气孔关闭，潜道表皮中的蒸腾速率比同化率受到的影响大得多。有潜道的叶片组织中的水分利用效率比完整叶片部分高约200%。我们的结果说明了一种植物可能将食草动物攻击造成的损失降至最低的新机制；即通过光合作用的负面影响与水分利用效率提高的积极影响之间的权衡。
