Sexual and temporal variations in floral scent in the subdioecious shrub Eurya japonica Thunb

Abstract

In many flowering plants, floral scents are a significant trait for visitors, playing an important role in attracting pollinators and/or detracting herbivores. The evolution of flowering plants from hermaphroditism to dioecy is often accompanied by sexual dimorphism in floral scent. In this study, floral scents emitted by different sexual morphs of the subdioecious shrub Eurya japonica Thunb. were collected using a dynamic headspace method, and sexual and temporal variations were evaluated by gas chromatography–mass spectrometry (GC–MS). Two volatiles, α‐pinene and linalool, were identified as the major components of floral scents in females, hermaphrodites, and males. The males emit higher amounts of floral scents, particularly α‐pinene, compared to females or hermaphrodites. Floral scents emitted by males generally decrease as flowers enter senescence, whereas those from females or hermaphrodites do not significantly differ. Intraspecific variations in floral scents of subdioecious species provided by this study would contribute to better understanding of sexual dimorphism in floral scent.

Sexual Differences in Eurya loquaiana Dunn Floral Scent and How Pollinators Respond

“…Sexual differentiation of floral scent might be expected in genus Eurya , as this difference has been observed both in E. japonica [ 22 , 23 ] and in this study. Miyazawa et al, reported the different compositions of essential oils of male and female flower buds in E. japonica [ 23 ], and Wang et al, compared the flower scent of E. japonica using a dynamic headspace method [ 22 ]. The same species was examined in these two studies; however, different sampling types lead to different results.…”

“…So far, most of the studies addressing Eurya plants have concentrated on morphology and anatomy; only a few studies have focused on floral scent components. Wang et al, reported two components of E. japonica : α-pinene and linalool [ 22 ]. Motooka et al, detected 87 compounds in essential oils from E. japonica flowers, and the main compounds were linalool, (9Z)-tricosene, and nonanal [ 50 ].…”

“…Miyazawa et al, (2016) found that α-terpineol and 3-carene were the most abundant compounds in male oil, while (2E)-hexenal and camphor were the most abundant compounds in female oil. Wang et al, (2018) observed no qualitative differences, but males emitted significantly higher amounts of α-pinene and marginally higher amounts of linalool compared with females or hermaphrodites [ 22 ]. In our study, the same compounds were detected in male, female, and hermaphrodite flowers, but the compositions varied ( Table 2 , Figure 3 ).…”

“…Despite their fragrant flowers, few studies have addressed the floral scent compositions of the Eurya species [ 22 , 23 ]. To better understand the floral scent of the genus Eurya and its ecological role in pollination, in this study, we investigate the floral scent components of E. loquaiana, using headspace–solid-phase micro-extraction (HS-SPME) combined with gas-chromatography–mass-spectrometry (GC-MS) [ 24 ].…”

An Update on the Function, Biosynthesis and Regulation of Floral Volatile Terpenoids

“…Solanaceae linalool and its enantiomers [26] Eurya japonica Thunb Theaceae α-pinene, linalool [27] Gardenia jasminoides Rubiaceae farnesene, Z-3-hexenyl tiglate, indole [28] Gelsemium sempervirens (L.) J. St.-Hil. Gelsemiaceae (Z)-α-ocimene, α-farnesene [29] Gossypium hirsutum Malvaceae (3S)-linalool GhTPS12 [30,31] Jasminum spp.…”