Root lesion nematodes (RLN) have negative impacts on legume-grass systems. These impacts might be moderated by bacterial feeding nematodes (BFN) presence. It remains unknown how these trophic groups of nematodes interactively impact plant productivity and dynamics of carbon (C) and nitrogen (N) in grass-legume mixtures. We addressed this research gap using inter-kingdom interactions in a model system. Chickpea and oat were grown in mono- and mixed cultures, and RLN and BFN were applied alone and in combination. Plant biomass, shoot C and N content and isotopic composition, and mineral N in soil were measured. RLN presence reduced root biomass across treatments. This reduction was stronger in the grass than the legume and was not modified by BFN. Nematodes increased plant shoot N concentrations. RLN and BFN had interactive effects on shoot nutrient concentration resulting in reduced shoot C concentration when both trophic groups were combined. Shoot δ15N data revealed transfer of symbiotically fixed N from chickpea to oat in the presence of RLN. However, this N transfer did not result in improved oat growth. Interactive effects of soil organisms can cascade aboveground, influencing C and N dynamics and ecosystem productivity.

中文翻译：

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土壤线虫的直接和间接营养相互作用影响鹰嘴豆和燕麦的营养

根病线虫 (RLN) 对豆科植物-草系统有负面影响。这些影响可能会因细菌摄食线虫 (BFN) 的存在而缓和。尚不清楚这些线虫营养组如何相互作用地影响草豆科植物混合物中的植物生产力和碳 (C) 和氮 (N) 动态。我们使用模型系统中的跨界交互来解决这一研究空白。鹰嘴豆和燕麦在单一和混合培养物中生长，RLN 和 BFN 单独和组合施用。测量了土壤中的植物生物量、枝条 C 和 N 含量和同位素组成以及矿物 N。RLN 的存在降低了整个处理的根生物量。这种减少在草中比豆类更强，并且没有被 BFN 改变。线虫增加了植物地上部 N 浓度。当两个营养组结合时，RLN 和 BFN 对枝条养分浓度有交互作用，导致枝条 C 浓度降低。芽 δ15N 数据显示在 RLN 存在下共生固定的 N 从鹰嘴豆转移到燕麦。然而，这种氮转移并没有导致燕麦生长的改善。土壤生物的交互作用可以在地上级联，影响 C 和 N 动态和生态系统生产力。