Chloromethane formation and degradation in the fern phyllosphere
Chloromethane formation and degradation in the fern phyllosphere
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DOI：
10.1016/j.scitotenv.2018.03.316
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发表时间：
2018-09-01
影响因子：
9.8
通讯作者：
Keppler, Frank
中科院分区：
文献类型：
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作者：
Jaeger, Nicole;Besaury, Ludovic;Keppler, Frank
氯甲烷（CH 3Cl）是大气中含量最丰富的卤代痕量气体。它在自然平流层臭氧破坏中起着重要作用。目前对全球CH 3Cl预算的估计是近似的。目前正在讨论土壤和植物中微生物降解CH 3Cl全球汇的强度。一些植物，特别是蕨类植物，已被确定为CH 3Cl的主要排放者。它们降解CH 3Cl的能力仍然不确定。在这项研究中，我们调查了潜在的叶片从3丰富的蕨类植物（薇菜，桫椤，鳞毛蕨filix-mas）产生和降解CH 3Cl通过测量其生产和消费率和稳定的碳和氢同位素的签名。研究的蕨类植物能够降解CH 3Cl，C的降解速率为2.1 - 17和0.3 - 0.9 μ g g（dw）（-1）天（-1）。cooperi和D. filix-mas分别取决于CH 3Cl补充和温度。剩余CH 3Cl的稳定碳同位素富集因子为-39 +/-13ppm，而氢的同位素分馏可忽略不计（-8 +/-19ppm）。与此相反，O.帝王草不消耗CH 3Cl，但产生CH 3Cl的速率为0.6 - 128 μ g g g（dw）（-1）day（-1），碳的稳定同位素值为-97 +/- 8 ppm，氢的稳定同位素值为-202 +/- 10 ppm。尽管3种蕨类植物表现出明显不同的形成和消费模式，但它们的叶相关细菌多样性没有显着差异。此外，我们没有检测到与唯一已知的氯甲烷利用途径“cmu”在微生物叶际的蕨类植物的基因。我们的研究表明，仍然未知的CH 3Cl在植物上的生物降解过程在大气CH 3Cl的全球循环中起着重要的作用。(C)2018 Elsevier B. V.版权所有。
Chloromethane (CH3Cl) is the most abundant halogenated trace gas in the atmosphere. It plays an important role in natural stratospheric ozone destruction. Current estimates of the global CH3Cl budget are approximate. The strength of the CH3Cl global sink by microbial degradation in soils and plants is under discussion. Some plants, particularly ferns, have been identified as substantial emitters of CH3Cl. Their ability to degrade CH3Cl remains uncertain. In this study, we investigated the potential of leaves from 3 abundant ferns (Osmunda regalis, Cyathea cooperi, Dryopteris filix-mas) to produce and degrade CH3Cl by measuring their production and consumption rates and their stable carbon and hydrogen isotope signatures. Investigated ferns are able to degrade CH3Cl at rates from 2.1 to 17 and 0.3 to 0.9 mu g g(dw)(-1) day(-1) for C. cooperi and D. filix-mas respectively, depending on CH3Cl supplementation and temperature. The stable carbon isotope enrichment factor of remaining CH3Cl was -39 +/- 13 parts per thousand, whereas negligible isotope fractionation was observed for hydrogen (-8 +/- 19 parts per thousand). In contrast, O. regalis did not consume CH3Cl, but produced it at rates ranging from 0.6 to 128 mu g g(dw)(-1) day(-1), with stable isotope values of -97 +/- 8 parts per thousand for carbon and -202 +/- 10 parts per thousand for hydrogen, respectively. Even though the 3 ferns showed clearly different formation and consumption patterns, their leaf-associated bacterial diversity was not notably different. Moreover, we did not detect genes associated with the only known chloromethane utilization pathway "cmu" in the microbial phyllosphere of the investigated ferns. Our study suggests that still unknown CH3Cl biodegradation processes on plants play an important role in global cycling of atmospheric CH3Cl. (C) 2018 Elsevier B.V. All rights reserved.