科研人員在一則研究中報(bào)告說(shuō)，落葉樹(shù)對(duì)去除大氣中的某些有機(jī)化合物有著驚人的功效,，這一發(fā)現(xiàn)對(duì)氣候模型有著重要的意義。
植物既是這些揮發(fā)性有機(jī)化合物（或稱VOCs）的一種接收器也是它們的一種來(lái)源,，當(dāng)植物物質(zhì)腐爛時(shí),，VOCs會(huì)進(jìn)入到大氣之中。 在大氣中,，VOCs可被氧化,，從而導(dǎo)致了氣溶膠的形成。氣溶膠可調(diào)節(jié)大氣的氧化能力,，并對(duì)氣候產(chǎn)生重要的反饋?zhàn)饔谩?/p>
各種模型通常將VOCs的攝取和降解像其它更常被研究的諸如臭氧這樣的生物源性氣體那樣來(lái)對(duì)待,，即它們大多數(shù)是不起反應(yīng)的。 Thomas Karl及其共同作者將模型與實(shí)驗(yàn)室的實(shí)驗(yàn)相結(jié)合,，他們現(xiàn)在提出,，VOCs實(shí)際上可與葉子的酶起反應(yīng)，因此它們可從大氣中被清除,。 這些結(jié)果提示,，植物實(shí)際上比人們過(guò)去認(rèn)為的可在污染區(qū)域中攝取更多的VOCs，尤其是在熱帶地區(qū),。 （生物谷Bioon.com）
生物谷推薦英文摘要：
Science DOI: 10.1126/science.1192534
Efficient Atmospheric Cleansing of Oxidized Organic Trace Gases by Vegetation
T. Karl,1,* P. Harley,1 L. Emmons,1 B. Thornton,2 A. Guenther,1 C. Basu,2 A. Turnipseed,1 K. Jardine3
The biosphere is the major source and sink of nonmethane volatile organic compounds (VOC) in the atmosphere. Gas phase chemical reactions initiate the removal of these compounds from the atmosphere, which ultimately proceeds via deposition at the surface or direct oxidation to CO or CO2. We performed ecosystem-scale flux measurements that show the removal of oxygenated VOC via dry deposition is substantially larger than currently assumed for deciduous ecosystems. Laboratory experiments indicate efficient enzymatic conversion and potential upregulation of various stress-related genes leading to enhanced uptake rates as a response to ozone and methyl vinyl ketone exposure or mechanical wounding. A revised scheme for the uptake of oxygenated VOCs, incorporated into a global chemistry–transport model, predicts appreciable regional changes in annual dry deposition fluxes.
1 National Center for Atmospheric Research, Boulder, CO, USA.
2 School of Biological Sciences, University of Northern Colorado, Greeley, CO, USA
3 Biosphere 2, University of Arizona, Tucson, AZ, USA.
