Department of Animal & Plant Sciences, P3 Centre for Translational Plant Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY, 14853, USA.
Nat Commun. 2018 Nov 9;9(1):4743. doi: 10.1038/s41467-018-07134-9.
Reactive nitrogen from human sources (e.g., nitrogen dioxide, NO) is taken up by plant roots following deposition to soils, but can also be assimilated by leaves directly from the atmosphere. Leaf uptake should alter plant metabolism and overall nitrogen balance and indirectly influence plant consumers; however, these consequences remain poorly understood. Here we show that direct foliar assimilation of NO increases levels of nitrogen-based defensive metabolites in leaves and reduces herbivore consumption and growth. These results suggest that atmospheric reactive nitrogen could have cascading negative effects on communities of herbivorous insects. We further show that herbivory induces a decrease in foliar uptake, indicating that consumers could limit the ability of vegetation to act as a sink for nitrogen pollutants (e.g., smog from mobile emissions). Our study suggests that the interactions of foliar uptake, plant defence and herbivory could have significant implications for understanding the environmental consequences of reactive nitrogen.
人类活动产生的活性氮（如二氧化氮，NO）在沉积到土壤后被植物根系吸收，但也可以直接从大气中被叶片吸收。叶片吸收应该会改变植物的新陈代谢和整体氮平衡，并间接地影响植物食者；然而，这些后果仍未得到充分理解。在这里，我们表明，NO 的直接叶面吸收会增加叶片中基于氮的防御性代谢物的水平，并减少草食者的消耗和生长。这些结果表明，大气活性氮可能对草食性昆虫群落产生级联的负面影响。我们进一步表明，草食性会诱导叶片吸收的减少，表明消费者可能会限制植被作为氮污染物（例如，来自移动排放的烟雾）汇的能力。我们的研究表明，叶片吸收、植物防御和草食性之间的相互作用可能对理解活性氮的环境后果具有重要意义。
