Contents lists available at ScienceDirect Phytochemistry journal homepage: www.elsevier.com/locate/phytochem Incomplete synchrony of inflorescence scent and temperature patterns in Arum maculatum L. (Araceae) Gertrud Marotz-Clausen a , Simone Jürschik b , Roman Fuchs a , Irmgard Schäffler a , Philipp Sulzer b , Marc Gibernau c , Stefan Dötterl a,∗ a Department of Biosciences, Plant Ecology, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria b IONICON Analytik Gesellschaft m.b.H., Eduard-Bodem-Gasse 3, 6020 Innsbruck, Austria c CNRS – University of Corsica, Laboratory Sciences for the Environment (SPE - UMR 6134), Natural Resources Project, Vignola – Route des Sanguinaires, 20000 Ajaccio, France ARTICLE INFO Keywords: Araceae Floral volatile compounds Non-invasive headspace technique Thermal desorption GC-MS PTR-TOFMS ABSTRACT In many Araceae both scent and heat production are known to temporally vary throughout anthesis, and in several species strong scents are released for pollinator attraction when thermogenesis is also strong. However, it is not known whether the temporal patterns of both scent emission and temperature are strictly synchronous and, for example, reach their maxima at the same time. We studied Arum maculatum, a brood-site deceptive species attracting its moth fly pollinators with strong fetid scents, to study temporal patterns in scent emission and temperature during anthesis. Inflorescence scents were collected and analysed by dynamic headspace and gas chromatography-mass spectrometry (GC-MS) or by proton-transfer-reaction-time-of-flight mass spectrometry (PTR-TOFMS), and the temperature of the appendix, which is the heating osmophore during pollinator attrac- tion, was recorded by a thermocouple. We overall found that scent emission and temperature patterns were strongly correlated. However, in none of the seven studied individuals was the highest amount of scent released at times with the maximum temperature difference. Thus, patterns of scent emission and temperature are somewhat asynchronous suggesting that high scent emission rates and temporal scent patterns in plants with thermogenesis cannot be solely explained by temperature patterns. This calls for more in-depth studies to better understand the interplay between scent emission and thermogenesis. 1. Introduction Flowers and inflorescences produce fragrant blends composed of various molecules, on average about 20–60 per specimen (Dudareva and Pichersky, 2006; Willmer, 2011). This bouquet of diverse, pre- dominantly lipophilic organic compounds of low molecular weight is one of the key communication channels between a plant and its polli- nator(s) (Dudareva and Pichersky, 2006; Willmer, 2011). Attraction and guidance of pollinators to and on flowers/inflorescences, respec- tively, are the main functions attributed to floral scent (Dobson, 2006; Knudsen et al., 2006). The bouquet of compounds is believed to be species-specific(Flügel, 2013; Knudsen et al., 2006; Schoonhoven et al., 2012) and contributes to flower constancy of pollinators (Knudsen et al., 2006) and reproductive isolation of plants (Dudareva and Pichersky, 2006). In several species, especially among basal angios- perms, e.g. in aroids or cycads, scent emission is accompanied by thermogenesis (Seymour et al., 2009). This heat production in flowers/ inflorescences will enhance the volatilisation of molecules that attract pollinators from distance, and, when pollinators land on the flowers/ inflorescences, heat guides them towards the reproductive organs of flowers/inflorescences as demonstrated by Angioy et al. (2004). Yet, heat alone does not attract pollinators from distance (Dormer, 1960; Kite et al., 1998; Knoll, 1926), but is a reward in some species for the endothermic pollinators (Seymour et al., 2003). In some aroid species it was also hypothesized to trigger anthesis (Albre et al., 2003; Bermadinger-Stabentheiner and Stabentheiner, 1995; Gibernau et al., 2005; Robacker et al., 1988), to influence other physiological processes related to flowering (Albre et al., 2003; Barabé et al., 2002; Seymour and Schultze-Motel, 1999), and to stimulate trapped pollinators (Albre et al., 2003). Both scent (Dötterl et al., 2012a,b) and heat (Barabé et al., 2002; Bay, 1995; Bermadinger-Stabentheiner and Stabentheiner, 1995; Gibernau et al., 2004; Seymour et al., 2010) productions are known to temporally vary throughout anthesis. In several Araceae, for example, it is known that strong scents are released for pollinator attraction only during a ’short‘ period of time, e.g. a few hours, during which there is https://doi.org/10.1016/j.phytochem.2018.07.001 Received 29 March 2018; Received in revised form 21 June 2018; Accepted 1 July 2018 ∗ Corresponding author. E-mail address: stefan.doetterl@sbg.ac.at (S. Dötterl). Phytochemistry 154 (2018) 77–84 0031-9422/ © 2018 Published by Elsevier Ltd. T