Leaf isoprene emission rate as a function of atmospheric CO2 concentration
Leaf isoprene emission rate as a function of atmospheric CO2 concentration
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DOI：
10.1111/j.1365-2486.2008.01803.x
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发表时间：
2009-05
影响因子：
11.6
通讯作者：
Michael J. Wilkinson;R. Monson;N. Trahan;Stanfield Y. Lee;E. Brown;R. B. Jackson;H. W. Polley;P. Fay;R. Fall
中科院分区：
文献类型：
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作者：
Michael J. Wilkinson;R. Monson;N. Trahan;Stanfield Y. Lee;E. Brown;R. B. Jackson;H. W. Polley;P. Fay;R. Fall
有相当大的兴趣在建模异戊二烯排放从陆地植被，因为这些排放量发挥了主要控制对流层的氧化能力。我们使用了一个独特的现场实验，采用连续梯度的CO2浓度从240至520 ppmv，以证明蓝桉异戊二烯排放量增加在最低的CO2浓度，这是类似的估计CO2浓度在最后一次冰期最大，相比380 ppmv，目前的CO2浓度。在最低CO2浓度下，枫香叶片的异戊二烯排放量没有增加。然而，异戊二烯排放率从这两个物种是较低的树木生长在520 ppmv CO2相比，树木生长在380 ppmv CO2。当生长在环境控制室中时，与400 ppmv CO2相比，在800 ppmv CO2下生长的美洲黑杨和美洲黑杨的树木表现出异戊二烯排放率降低30-40%。当在1200 ppmv CO2下生长时，与600 ppmv CO2相比，P. tremuloides表现出33%的减少。我们使用目前的叶片异戊二烯排放模型来证明，如果不考虑异戊二烯的CO2抑制，会出现重大错误。为了减轻这些错误，我们提出了一个新的异戊二烯排放模型，描述其响应大气CO2浓度的变化。该模型的逻辑是基于假设的竞争之间的胞质和叶绿体丙酮酸，异戊二烯生物合成的主要底物之一的过程。
There is considerable interest in modeling isoprene emissions from terrestrial vegetation, because these emissions exert a principal control over the oxidative capacity of the troposphere. We used a unique field experiment that employs a continuous gradient in CO2 concentration from 240 to 520 ppmv to demonstrate that isoprene emissions in Eucalyptus globulus were enhanced at the lowest CO2 concentration, which was similar to the estimated CO2 concentrations during the last Glacial Maximum, compared with 380 ppmv, the current CO2 concentration. Leaves of Liquidambar styraciflua did not show an increase in isoprene emission at the lowest CO2 concentration. However, isoprene emission rates from both species were lower for trees grown at 520 ppmv CO2 compared with trees grown at 380 ppmv CO2. When grown in environmentally controlled chambers, trees of Populus deltoides and Populus tremuloides exhibited a 30–40% reduction in isoprene emission rate when grown at 800 ppmv CO2, compared with 400 ppmv CO2. P. tremuloides exhibited a 33% reduction when grown at 1200 ppmv CO2, compared with 600 ppmv CO2. We used current models of leaf isoprene emission to demonstrate that significant errors occur if the CO2 inhibition of isoprene is not taken into account. In order to alleviate these errors, we present a new model of isoprene emission that describes its response to changes in atmospheric CO2 concentration. The model logic is based on assumed competition between cytosolic and chloroplastic processes for pyruvate, one of the principal substrates of isoprene biosynthesis.