Ecology and evolution of light-dependent and light-independent phytogenic volatile organic carbon.

The low molecular weight hydrocarbons produced by plants form a uniquely exciting group of compounds. Produced by a common biosynthetic route, they play multiple and complex roles in organismal, ecological, and atmospheric processes. While some of these compounds have clearly identified functions within plants, others are made for reasons not yet fully understood. Here, both light-dependent and light-independent emissions are reviewed, together with regulation of production and possible functions of light-dependent volatile organic carbon (VOC). In addition to issues regarding the phylogenetic origins of VOC emissions, the origins of the pivotal enzymes that give rise to the observed emission phenotypes are discussed. Studies on the evolution and regulation of their production and emission provide an amazing opportunity for scientists working from the molecular to the tropospheric scales to interact. Contents Summary 199 I. Introduction 199 II. Light-independent emissions 200 III. Light-dependent emissions 201 IV. Regulation of production 202 V. Possible functions of light-dependent VOCs 204 VI. Evolutionary aspects of phytogenic VOC 206 Acknowledgements 206 References 209.