Hempel Stefan, Stein Claudia, Unsicker Sybille B, Renker Carsten, Auge Harald, Weisser Wolfgang W, Buscot François
Department of Soil Ecology, Helmholtz Centre for Environmental Research-UFZ, Theodor-Lieser-Strasse 4, 06120 Halle, Germany.
Oecologia. 2009 May;160(2):267-77. doi: 10.1007/s00442-009-1294-0. Epub 2009 Feb 14.
The majority of plants are involved in symbioses with arbuscular mycorrhizal fungi (AMF), and these associations are known to have a strong influence on the performance of both plants and insect herbivores. Little is known about the impact of AMF on complex trophic chains, although such effects are conceivable. In a greenhouse study we examined the effects of two AMF species, Glomus intraradices and G. mosseae on trophic interactions between the grass Phleum pratense, the aphid Rhopalosiphum padi, and the parasitic wasp Aphidius rhopalosiphi. Inoculation with AMF in our study system generally enhanced plant biomass (+5.2%) and decreased aphid population growth (-47%), but there were no fungal species-specific effects. When plants were infested with G. intraradices, the rate of parasitism in aphids increased by 140% relative to the G. mosseae and control treatment. When plants were associated with AMF, the developmental time of the parasitoids decreased by 4.3% and weight at eclosion increased by 23.8%. There were no clear effects of AMF on the concentration of nitrogen and phosphorus in plant foliage. Our study demonstrates that the effects of AMF go beyond a simple amelioration of the plants' nutritional status and involve rather more complex species-specific cascading effects of AMF in the food chain that have a strong impact not only on the performance of plants but also on higher trophic levels, such as herbivores and parasitoids.
大多数植物都与丛枝菌根真菌（AMF）形成共生关系，而且已知这些共生关系对植物和食草昆虫的生长表现都有很大影响。尽管可以想象AMF会产生这样的影响，但对于AMF对复杂营养链的影响却知之甚少。在一项温室研究中，我们研究了两种AMF物种，即根内球囊霉和摩西球囊霉，对草地早熟禾、禾谷缢管蚜和寄生蜂燕麦蚜茧蜂之间营养相互作用的影响。在我们的研究系统中接种AMF通常会提高植物生物量（+5.2%）并降低蚜虫种群增长率（-47%），但没有真菌物种特异性效应。当植物受到根内球囊霉侵染时，相对于摩西球囊霉和对照处理，蚜虫的寄生率提高了140%。当植物与AMF共生时，寄生蜂的发育时间缩短了4.3%，羽化时的体重增加了23.8%。AMF对植物叶片中氮和磷的浓度没有明显影响。我们的研究表明，AMF的影响不仅仅是简单改善植物的营养状况，还涉及AMF在食物链中更复杂的物种特异性级联效应，这不仅对植物的生长表现有很大影响，而且对更高营养级，如食草动物和寄生蜂也有很大影响。
