Modeling the isoprene emission rate from leaves.
The leaves of many plants emit isoprene (2-methyl-1,3-butadiene) to the atmosphere, a process which has important ramifications for global and regional atmospheric chemistry. Quantitation of leaf isoprene emission and its response to environmental variation are described by empirically derived equations that replicate observed patterns, but have been linked only in some cases to known biochemical and physiological processes. Furthermore, models have been proposed from several independent laboratories, providing multiple approaches for prediction of emissions, but with little detail provided as to how contrasting models are related. In this review we provide an analysis as to how the most commonly used models have been validated, or not, on the basis of known biochemical and physiological processes. We also discuss the multiple approaches that have been used for modeling isoprene emission rate with an emphasis on identifying commonalities and contrasts among models, we correct some mathematical errors that have been propagated through the models, and we note previously unrecognized covariances within processes of the models. We come to the conclusion that the state of isoprene emission modeling remains highly empirical. Where possible, we identify gaps in our knowledge that have prevented us from achieving a greater mechanistic foundation for the models, and we discuss the insight and data that must be gained to fill those gaps.
School of Natural Resources and the Environment and Laboratory for Tree Ring Research, University of Arizona, Tucson, Arizona 85721, USA.
Russell K
RK
Monson
Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research, Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany.
Rüdiger
R
Grote
Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Ülo
Ü
Niinemets
Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, 85764 Neuherberg, Germany.
Jörg-Peter
JP
Schnitzler
D000465:Algorithms; D019883:Alkyl and Aryl Transferases / Q000737:chemistry*; D002070:Butadienes / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D055864:Droughts; D004579:Electron Transport; D004789:Enzyme Activation; D045782:Hemiterpenes / Q000737:chemistry*; D008954:Models, Biological; D010420:Pentanes / Q000737:chemistry*; D017785:Photons; D010788:Photosynthesis; D018515:Plant Leaves / Q000737:chemistry* / Q000502:physiology; D012621:Seasons; D013696:Temperature
D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene; D002245:Carbon Dioxide; D019883:Alkyl and Aryl Transferases; C093854:isoprene synthase