| Title: | A unifying conceptual model for the environmental responses of isoprene emissions from plants |
| Author(s): | Morfopoulos C; Prentice IC; Keenan TF; Friedlingstein P; Medlyn BE; Penuelas J; Possell M; |
| Address: | "Department of Life Sciences, Imperial College, Silwood Park, Ascot SL5 7PY, UK" |
| ISSN/ISBN: | 1095-8290 (Electronic) 0305-7364 (Print) 0305-7364 (Linking) |
| Abstract: | "BACKGROUND AND AIMS: Isoprene is the most important volatile organic compound emitted by land plants in terms of abundance and environmental effects. Controls on isoprene emission rates include light, temperature, water supply and CO2 concentration. A need to quantify these controls has long been recognized. There are already models that give realistic results, but they are complex, highly empirical and require separate responses to different drivers. This study sets out to find a simpler, unifying principle. METHODS: A simple model is presented based on the idea of balancing demands for reducing power (derived from photosynthetic electron transport) in primary metabolism versus the secondary pathway that leads to the synthesis of isoprene. This model's ability to account for key features in a variety of experimental data sets is assessed. KEY RESULTS: The model simultaneously predicts the fundamental responses observed in short-term experiments, namely: (1) the decoupling between carbon assimilation and isoprene emission; (2) a continued increase in isoprene emission with photosynthetically active radiation (PAR) at high PAR, after carbon assimilation has saturated; (3) a maximum of isoprene emission at low internal CO2 concentration (ci) and an asymptotic decline thereafter with increasing ci; (4) maintenance of high isoprene emissions when carbon assimilation is restricted by drought; and (5) a temperature optimum higher than that of photosynthesis, but lower than that of isoprene synthase activity. CONCLUSIONS: A simple model was used to test the hypothesis that reducing power available to the synthesis pathway for isoprene varies according to the extent to which the needs of carbon assimilation are satisfied. Despite its simplicity the model explains much in terms of the observed response of isoprene to external drivers as well as the observed decoupling between carbon assimilation and isoprene emission. The concept has the potential to improve global-scale modelling of vegetation isoprene emission" |
| Keywords: | "Butadienes/*metabolism Carbon Dioxide/metabolism Electrons *Environment Hemiterpenes/*metabolism Light *Models, Biological NADP/metabolism Pentanes/*metabolism Photosynthesis Plants/*metabolism Temperature Isoprene carbon dioxide electron transport isopre;" |
| Notes: | "MedlineMorfopoulos, Catherine Prentice, Iain C Keenan, Trevor F Friedlingstein, Pierre Medlyn, Belinda E Penuelas, Josep Possell, Malcolm eng Research Support, Non-U.S. Gov't England 2013/09/21 Ann Bot. 2013 Nov; 112(7):1223-38. doi: 10.1093/aob/mct206. Epub 2013 Sep 19" |
