Volume 30, Issue 2 p. 139-147
RESEARCH ARTICLE

Compositional changes of the floral scent volatile emissions from Asian skunk cabbage (Symplocarpus renifolius, Araceae) over flowering sex phases

Suguru Oguri

Corresponding Author

Suguru Oguri

Department of Northern Biosphere Agriculture, Faculty of Bioindustry, Tokyo University of Agriculture, Yasaka, Abashiri, Hokkaido, Japan

Correspondence

Suguru Oguri, Department of Northern Biosphere Agriculture, Faculty of Bioindustry, Tokyo University of Agriculture, Yasaka, Abashiri, Hokkaido, Japan.

Email: [email protected]

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Kensuke Sakamaki

Kensuke Sakamaki

Technical Research Institute, R&D Center, T. Hasegawa Co., Ltd., Kariyado, Nakahara-ku, Kawasaki-shi, Japan

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Hikaru Sakamoto

Hikaru Sakamoto

Department of Northern Biosphere Agriculture, Faculty of Bioindustry, Tokyo University of Agriculture, Yasaka, Abashiri, Hokkaido, Japan

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Kikue Kubota

Kikue Kubota

Department of Food and Cosmetic Science, Graduate School of Bioindustry, Tokyo University of Agriculture, Yasaka, Abashiri, Hokkaido, Japan

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First published: 31 October 2018
Citations: 8

Abstract

Introduction

Flowering of the Asian skunk cabbage (Symplocarpus renifolius, Araceae) shows a sequential expression of female, bisexual and male sex phases. The protogynous thermogenic inflorescence has unpleasant odours, but the contributing chemical composition is poorly understood.

Objective

To determine the volatile composition of odour emissions from each S. renifolius flowering phase.

Methodology

The dynamic headspace method was used to collect floral volatiles from six intact S. renifolius inflorescences in their natural habitat. Collected volatiles from the three flowering phases were analysed using gas chromatography–mass spectrometry/olfactometry (GC–MS/O).

Results

Female-phase inflorescences were characterised by an earthy-rotten-minty odour, while male-phase inflorescences typically exhibited a rotten-oily odour. Approximately 160 compounds were detected in volatiles from the three phases. Common to all phases were 3-methylbutyl 3-methylbutanoate, 1,8-cineole, dimethyl disulphide and sabinene, together accounting for 52 to 54% of total volatiles. GC–MS/O revealed that at least 28 volatiles including eight S-containing compounds contributed to the unpleasant odour of S. renifolius. Among them, dimethyl disulphide (onion-like), methional (potato-like), and the tentatively identified methyl dithioformate (garlic-like) were intense odour-active compounds in each floral phase. Additionally, 2-isopropyl-3-methoxypyrazine (IPMP) was a major contributor to the earthy odour that was characteristic of the female phase.

Conclusions

No marked changes were observed in floral volatile compositions over the three flowering phases of S. renifolius. Instead, flower phase-dependent proportional changes of minor components (e.g. IPMP and 2,3-butanedione) altered the odour characteristics between the female and male phases.