scholarly journals Evolution and diversity of floral scent chemistry in the euglossine bee-pollinated orchid genusGongora

2016 ◽  
Vol 118 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Molly C. Hetherington-Rauth ◽  
Santiago R. Ramírez
Keyword(s):  
AoB Plants ◽  
2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Katharina Brandt ◽  
Isabel Cristina Machado ◽  
Daniela Maria do Amaral Ferraz Navarro ◽  
Stefan Dötterl ◽  
Manfred Ayasse ◽  
...  

Abstract Dioecy in angiosperms is often associated with sexual dimorphism in floral traits other than the sexual organs. Species of the neotropical orchid genus Catasetum produce unisexual flowers characterized by a remarkable morphological sexual dimorphism. Catasetum species emit strong floral perfumes that act as both signal and reward for male euglossine bee pollinators. Although the role of floral perfumes of Catasetum in attracting euglossine pollinators is well investigated, little is known about whether perfumes differ between floral sexes and, if they do, whether this chemical dimorphism influences the pollination ecology of the plants. Taking Catasetum arietinum as a model species, our aim was to observe the behaviour of pollinators on male and female flowers and to compare scent properties (i.e. chemical composition, total amount and temporal fluctuation) of male and female flowers. Floral scent samples were collected by using dynamic headspace methods and were analysed via gas chromatography coupled with mass spectroscopy (GC-MS). Catasetum arietinum is pollinated by males of two Euglossa species (i.e. E. nanomelanotricha and E. securigera). Bees approached male and female inflorescences of C. arietinum in similar proportions but landed significantly more often and spent more time on female flowers, which emitted more scent than male flowers. Furthermore, the amount of scent emitted varied across the different times of sampling, corresponding to the pattern of the diel foraging activity of pollinating bees on male and female flowers. The chemical composition of scents differed significantly between sexes. The two major compounds (Z)-methyl-p-methoxycinnamate and (E)-geranyl geraniol contributed most to this difference. This is the first case of sexual dimorphism reported in orchid floral perfumes. We discuss the influence of sex-specific floral scents on the behaviour of euglossine pollinators and offer new insights into the ecological and evolutionary significance of divergence in floral scents among dioecious plants.


Diversity ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 5
Author(s):  
Herbert Braunschmid ◽  
Robin Guilhot ◽  
Stefan Dötterl

Floral scent is an important trait in plant–pollinator interactions. It not only varies among plant species but also among populations within species. Such variability might be caused by various non–selective factors, or, as has been shown in some instances, might be the result of divergent selective pressures exerted by variable pollinator climates. Cypripedium calceolus is a Eurasian deceptive orchid pollinated mainly by bees, which spans wide altitudinal and latitudinal gradients in mainly quite isolated populations. In the present study, we investigated whether pollinators and floral scents vary among different latitudes. Floral scents of three C. calceolus populations in the Southern Alps were collected by dynamic headspace and analyzed by gas chromatography coupled to mass spectrometry (GC/MS). These data were completed by previously published scent data of the Northern Alps and Scandinavia. The scent characteristics were compared with information on pollinators recorded for present study or available in the literature. More than 80 scent compounds were overall recorded from plants of the three regions, mainly aliphatics, terpenoids, and aromatics. Seven compounds were found in all samples, and most samples were dominated by linalool and octyl acetate. Although scents differed among regions and populations, the main compounds were similar among regions. Andrena and Lasioglossum species were the main pollinators in all three regions, with Andrena being relatively more abundant than Lasioglossum in Scandinavia. We discuss natural selection mediated by pollinators and negative frequency–dependent selection as possible reasons for the identified variation of floral scent within and among populations and regions.


2019 ◽  
Vol 20 (13) ◽  
pp. 3235 ◽  
Author(s):  
Yanguo Ke ◽  
Farhat Abbas ◽  
Yiwei Zhou ◽  
Rangcai Yu ◽  
Yuechong Yue ◽  
...  

Auxin plays a key role in different plant growth and development processes, including flower opening and development. The perception and signaling of auxin depend on the cooperative action of various components, among which auxin/indole-3-acetic acid (Aux/IAA) proteins play an imperative role. In a recent study, the entire Aux/IAA gene family was identified and comprehensively analyzed in Hedychium coronarium, a scented species used as an ornamental plant for cut flowers. Phylogenetic analysis showed that the Aux/IAA gene family in H. coronarium is slightly contracted compared to Arabidopsis, with low levels of non-canonical proteins. Sequence analysis of promoters showed numerous cis-regulatory elements related to various phytohormones. HcIAA genes showed distinct expression patterns in different tissues and flower developmental stages, and some HcIAA genes showed significant responses to auxin and ethylene, indicating that Aux/IAAs may play an important role in linking hormone signaling pathways. Based on the expression profiles, HcIAA2, HcIAA4, HcIAA6 and HcIAA12, were selected as candidate genes and HcIAA2 and HcIAA4 were screened for further characterization. Downregulation of HcIAA2 and HcIAA4 by virus-induced gene silencing in H. coronarium flowers modified the total volatile compound content, suggesting that HcIAA2 and HcIAA4 play important roles in H. coronarium floral scent formation. The results presented here will provide insights into the putative roles of HcIAA genes and will assist the elucidation of their precise roles during floral scent formation.


Author(s):  
Patrick Stamm ◽  
Florian Etl ◽  
Artur Campos D. Maia ◽  
Stefan Dötterl ◽  
Stefan Schulz

2021 ◽  
Vol 288 ◽  
pp. 110218
Author(s):  
Ruijie Hao ◽  
Shuting Yang ◽  
Zhongqiang Zhang ◽  
Yajing Zhang ◽  
Jun Chang ◽  
...  

Oikos ◽  
1999 ◽  
Vol 85 (3) ◽  
pp. 409 ◽  
Author(s):  
Jette T. Knudsen ◽  
Susanna Andersson ◽  
Peter Bergman

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Alexander Haverkamp ◽  
Felipe Yon ◽  
Ian W Keesey ◽  
Christine Mißbach ◽  
Christopher Koenig ◽  
...  

Pollination by insects is essential to many ecosystems. Previously, we have shown that floral scent is important to mediate pollen transfer between plants (<xref ref-type="bibr" rid="bib16">Kessler et al., 2015</xref>). Yet, the mechanisms by which pollinators evaluate volatiles of single flowers remained unclear. Here, Nicotiana attenuata plants, in which floral volatiles have been genetically silenced and its hawkmoth pollinator, Manduca sexta, were used in semi-natural tent and wind-tunnel assays to explore the function of floral scent. We found that floral scent functions to increase the fitness of individual flowers not only by increasing detectability but also by enhancing the pollinator's foraging efforts. Combining proboscis choice tests with neurophysiological, anatomical and molecular analyses we show that this effect is governed by newly discovered olfactory neurons on the tip of the moth's proboscis. With the tip of their tongue, pollinators assess the advertisement of individual flowers, an ability essential for maintaining this important ecosystem service.


Sign in / Sign up

Export Citation Format

Share Document