IPSP-CNR, Institute for Sustainable Plant Protection, National Research Council, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Florence, Italy.
IVALSA-CNR, Trees and Timber Institute, National Research Council, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Florence, Italy; Department of Agri-Food Production and Environmental Sciences, University of Florence, Viale delle Idee 30, 50019, Sesto Fiorentino, Florence, Italy.
Environ Pollut. 2016 Jun;213:988-995. doi: 10.1016/j.envpol.2015.12.047. Epub 2016 Jan 22.
Emission of BVOC (Biogenic Volatile Organic Compounds) from plant leaves in response to ozone exposure (O3) and nitrogen (N) fertilization is poorly understood. For the first time, BVOC emissions were explored in a forest tree species (silver birch, Betula pendula) exposed for two years to realistic levels of O3 (35, 48 and 69 ppb as daylight average) and N (10, 30 and 70 kg ha(-1) yr(-1), applied weekly to the soil as ammonium nitrate). The main BVOCs emitted were: α-pinene, β-pinene, limonene, ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and hexanal. Ozone exposure increased BVOC emission and reduced total leaf area. The effect on emission was stronger when a short-term O3 metric (concentrations at the time of sampling) rather than a long-term one (AOT40) was used. The effect of O3 on total leaf area was not able to compensate for the stimulation of emission, so that responses to O3 at leaf and whole-plant level were similar. Nitrogen fertilization increased total leaf area, decreased α-pinene and β-pinene emission, and increased ocimene, hexanal and DMNT emission. The increase of leaf area changed the significance of the emission response to N fertilization for most compounds. Nitrogen fertilization mitigated the effects of O3 exposure on total leaf area, while the combined effects of O3 exposure and N fertilization on BVOC emission were additive and not synergistic. In conclusion, O3 exposure and N fertilization have the potential to affect global BVOC via direct effects on plant emission rates and changes in leaf area.
植物叶片排放 BVOC（生物挥发性有机化合物）对臭氧暴露（O3）和氮（N）施肥的响应机制尚未完全阐明。本研究首次在林分树种（银桦，Betula pendula）中探索了 BVOC 排放，该树种在两年内暴露于现实水平的 O3（白天平均为 35、48 和 69 ppb）和 N（10、30 和 70 kg ha(-1) yr(-1)，每周作为硝酸铵施用于土壤）。排放的主要 BVOC 为：α-蒎烯、β-蒎烯、柠檬烯、罗勒烯、（E）-4,8-二甲基-1,3,7-壬三烯（DMNT）和己醛。臭氧暴露增加了 BVOC 排放并减少了总叶面积。当使用短期 O3 指标（采样时的浓度）而不是长期指标（AOT40）时，对排放的影响更强。O3 对总叶面积的影响无法补偿排放的刺激，因此叶片和整株植物水平对 O3 的响应相似。氮施肥增加了总叶面积，减少了 α-蒎烯和 β-蒎烯的排放，增加了罗勒烯、己醛和 DMNT 的排放。叶面积的增加改变了大多数化合物对氮施肥的排放响应的重要性。氮施肥减轻了臭氧暴露对总叶面积的影响，而臭氧暴露和氮施肥的综合影响对 BVOC 排放是相加的，而不是协同的。总之，臭氧暴露和氮施肥有可能通过直接影响植物排放速率和叶面积变化来影响全球 BVOC。
