Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland.
Tree Physiol. 2018 Oct 1;38(10):1461-1475. doi: 10.1093/treephys/tpy029.
The changing climate will expose boreal forests to rising temperatures, increasing soil nitrogen (N) levels and an increasing risk of herbivory. The single and interaction effects of warming (+2 °C increase), moderate N addition (30 kg ha-1 year-1) and bark herbivory by large pine weevil (Hylobius abietis L.) on growth and emissions of biogenic volatile organic compounds (BVOCs) from shoots of Scots pine (Pinus sylvestris L.) seedlings were studied in growth chambers over 175 days. In addition, warming and N addition effects on shoot net photosynthesis (Pn) were measured. Nitrogen addition increased both shoot and root dry weights, whereas warming, in combination with herbivory, reduced stem height growth. Warming together with N addition increased current-year shoot Pn, whereas N effects on previous-year shoot Pn were variable over time. Warming decreased non-oxygenated monoterpene (MT) emissions in June and increased them in July. Of individual MT compounds, α-pinene, δ-3-carene, γ-terpinene and terpinolene were among the most frequently responsive compounds in warming treatments in the May-July period. Sesquiterpene emissions were observed only from warming treatments in July. Moderate N addition increased oxygenated monoterpenes in May, and MTs in June and September. However, N addition effect on MTs in June was clearer without warming than with warming. Bark herbivory tended to increase MT emissions in combination with warming and N addition 3 weeks after the damage caused by weevils. Of individual compounds in other BVOC blends, herbivory increased the emissions of methyl-benzene, benzene and hexanal in July. Hence, though both warming and N addition have a potential to change BVOC emissions from Scots pines, the N effect may also be partly cancelled by warming. Furthermore, herbivory pressure in combination with climate warming and N addition may, at least periodically, increase BVOC release to the atmosphere from young Scots pine seedlings.
气候变化将使北方森林面临气温升高、土壤氮（N）含量增加以及食草动物危害风险增加等问题。本研究在生长室内通过 175 天的时间，研究了增温（升高 2°C）、中度施氮（30kg ha-1 year-1）和松扁象甲（Hylobius abietis L.）取食树皮对辐射松（Pinus sylvestris L.）幼苗枝条生长和生物源挥发性有机化合物（BVOCs）排放的单一和交互作用。此外，还测量了增温和施氮对枝条净光合（Pn）的影响。施氮增加了枝条和根系的干重，而增温与食草动物的共同作用则降低了茎干的生长高度。增温与施氮共同作用增加了当年生枝条的净光合，而施氮对前一年枝条净光合的影响则随时间而变化。增温降低了 6 月非氧化型单萜（MT）的排放，而增加了 7 月 MT 的排放。在 5 月至 7 月期间，在增温处理中，α-蒎烯、δ-3-蒈烯、γ-萜品烯和萜品油烯等个别 MT 化合物是最常响应的化合物之一。在 7 月仅从增温处理中观察到倍半萜的排放。中度施氮增加了 5 月的含氧单萜，6 月和 9 月的 MT。然而，在没有增温的情况下，施氮对 MT 的影响比有增温时更明显。在象甲取食后 3 周，与增温和施氮共同作用下，取食树皮会增加 MT 的排放。在其他 BVOC 混合物中的个别化合物中，取食增加了 7 月的甲基苯、苯和己醛的排放。因此，尽管增温和施氮都有可能改变辐射松的 BVOC 排放，但氮的影响也可能部分被增温所抵消。此外，在气候变暖以及氮添加的共同作用下，食草动物的压力可能会至少在某些时期增加幼年辐射松幼苗向大气中释放 BVOC。
