Agathokleous Evgenios, Kitao Mitsutoshi, Wang Xiaona, Mao Qiaozhi, Harayama Hisanori, Manning William J, Koike Takayoshi
Key Laboratory of Agrometeorology of Jiangsu Province, Institute of Applied Ecology, Nanjing University of Information Science and Technology (NUIST), Nanjing, 210044 People's Republic of China.
Division of Environment and Resources Research, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan.
J For Res (Harbin). 2021;32(5):2047-2057. doi: 10.1007/s11676-020-01223-6. Epub 2020 Sep 30.
Japanese larch ( (Lamb.) Carr.) and its hybrid are economically important coniferous trees widely grown in the Northern Hemisphere. Ground-level ozone (O) concentrations have increased since the pre-industrial era, and research projects showed that Japanese larch is susceptible to elevated O exposures. Therefore, methodologies are needed to (1) protect Japanese larch against O damage and (2) conduct biomonitoring of O in Japanese larch forests and, thus, monitor O risks to Japanese larch. For the first time, this study evaluates whether the synthetic chemical ethylenediurea (EDU) can protect Japanese larch against O damage, in two independent experiments. In the first experiment, seedling communities, simulating natural regeneration, were treated with EDU (0, 100, 200, and 400 mg L) and exposed to either ambient or elevated O in a growing season. In the second experiment, individually-grown saplings were treated with EDU (0, 200 and 400 mg L) and exposed to ambient O in two growing seasons and to elevated O in the succeeding two growing seasons. The two experiments revealed that EDU concentrations of 200-400 mg L could protect Japanese larch seedling communities and individual saplings against O-induced inhibition of growth and productivity. However, EDU concentrations ≤ 200 mg L did offer only partial protection when seedling communities were coping with higher level of O-induced stress, and only 400 mg EDU L fully protected communities under higher stress. Therefore, we conclude that among the concentrations tested the concentration offering maximum protection to Japanese larch plants under high competition and O-induced stress is that of 400 mg EDU L. The results of this study can provide a valuable resource of information for applied forestry in an O-polluted world.
日本落叶松（(Lamb.) Carr.）及其杂种是经济上重要的针叶树，在北半球广泛种植。自工业化前时代以来，地面臭氧（O₃）浓度有所增加，研究项目表明日本落叶松易受臭氧暴露增加的影响。因此，需要方法来（1）保护日本落叶松免受臭氧损害，以及（2）在日本落叶松林进行臭氧生物监测，从而监测日本落叶松面临的臭氧风险。本研究首次在两项独立实验中评估合成化学物质乙二脲（EDU）是否能保护日本落叶松免受臭氧损害。在第一个实验中，模拟自然更新的幼苗群落用EDU（0、100、200和400 mg/L）处理，并在生长季节暴露于环境臭氧或升高的臭氧环境中。在第二个实验中，单独种植的幼树用EDU（0、200和400 mg/L）处理，在两个生长季节暴露于环境臭氧中，并在随后的两个生长季节暴露于升高的臭氧中。这两项实验表明，200 - 400 mg/L的EDU浓度可以保护日本落叶松幼苗群落和单个幼树免受臭氧诱导的生长和生产力抑制。然而，当幼苗群落应对更高水平的臭氧诱导胁迫时，≤200 mg/L的EDU浓度仅提供部分保护，只有400 mg/L的EDU能在更高胁迫下完全保护群落。因此，我们得出结论，在所测试的浓度中，在高竞争和臭氧诱导胁迫下为日本落叶松植物提供最大保护的浓度是400 mg/L的EDU。本研究结果可为臭氧污染环境下的应用林业提供宝贵的信息资源。
