Environmental variables controlling the uptake of carbonyl sulfide by lichens
Environmental variables controlling the uptake of carbonyl sulfide by lichens
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DOI：
10.1029/2000jd900436
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发表时间：
2000-11-27
影响因子：
4.4
通讯作者：
Kesselmeier, J
中科院分区：
文献类型：
--
作者：
Kuhn, U;Kesselmeier, J
在实验室条件下，研究了加州中部疏林地衣的代表植物-曼氏枝花（Ramalinamenziesii）对大气羰基硫（COS）的吸收。通过使用动态比色皿系统，在气候室条件下研究了COS吸收的控制参数。叶状体的含水量，对地衣的整体生理是必不可少的，被认为是基本的微量气体交换的重要性，30%的水含量是COS吸收的近似最低值，随着增加的活动高达200%的水含量。此外，实际的大气混合比有显着的影响，COS的吸收被发现是一个线性函数的环境COS混合比导致的补偿点低至37 ppt。25 ℃的最适温度是COS吸收的生理基础。在碳酸酐酶的特异性抑制剂存在下对COS消耗的抑制证明了这种酶对于摄取具有关键相关性。所有这些控制COS沉积的变量被集成到一个摄取算法来模拟这种地衣的交换行为。证明了该模型对现场数据的适用性。以干重为基础的吸收率在优化条件下（25 ℃; 450 pptCOS）达到0.17 +/- 0.09 pmol g（-1）s（-1）（即4.2 +/- 2.2 pmol m（-2）s（-1）菌体表面积）。地衣对全球COS汇强度的贡献约为0.3 Tg a（-1），不是一个主要的，但一个重要的汇。
The uptake of atmospheric carbonyl sulfide (COS) by the lichen species Ramalina menziesii, representative fur the open oaf; woodland in central California, was studied under laboratory conditions. By use of a dynamic cuvette system, the controlling parameters for the COS uptake were investigated under climate chamber conditions. The thallus water content, essential for the overall physiology of lichens, was found to be of basic importance for the trace gas exchange, A water content of 30% was the approximate minimum for COS uptake, with increasing activity up to a water content of 200%. Additionally, actual atmospheric mixing ratios have a significant influence on the exchange, The COS uptake was found to be a linear function of the ambient COS mixing ratio resulting in a compensation point as low as 37 ppt. A temperature optimum of 25 degreesC was indicative of a physiological basis of the COS uptake. The inhibition of the COS consumption in the presence of a specific inhibitor for the enzyme carbonic anhydrase proved this enzyme to be of key relevance for the uptake. All these variables controlling the COS deposition were integrated into an uptake algorithm to model the exchange behavior of this lichen. The applicability of the model to field data is demonstrated. Uptake rates on a dry weight basis normalized to optimized conditions (25 degreesC; 450 ppt COS) reached 0.17 +/- 0.09 pmol g(-1) s(-1) (i.e, 4.2 +/- 2.2 pmol m(-2) s(-1) thallus surface area, respectively). The contribution of lichens to the global COS sink strength is assigned to be about 0.3 Tg a(-1), representing not a major but a significant sink.