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Skaliter O, Kitsberg Y, Sharon E, Shklarman E, Shor E, Masci T, Yue Y, Arien Y, Tabach Y, Shafir S, Vainstein A. Spatial patterning of scent in petunia corolla is discriminated by bees and involves the ABCG1 transporter. Plant J 2021; 106:1746-1758. [PMID: 33837586 DOI: 10.1111/tpj.15269] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/23/2021] [Accepted: 03/31/2021] [Indexed: 05/27/2023]
Abstract
Floral guides are patterned cues that direct the pollinator to the plant reproductive organs. The spatial distribution of showy visual and olfactory traits allows efficient plant-pollinator interactions. Data on the mechanisms underlying floral volatile patterns or their interactions with pollinators are lacking. Here we characterize the spatial emission patterns of volatiles from the corolla of the model plant Petunia × hybrida and reveal the ability of honeybees to distinguish these patterns. Along the adaxial epidermis, in correlation with cell density, the petal base adjacent to reproductive organs emitted significantly higher levels of volatiles than the distal petal rim. Volatile emission could also be differentiated between the two epidermal surfaces: emission from the adaxial side was significantly higher than that from the abaxial side. Similar emission patterns were also observed in other petunias, Dianthus caryophyllus (carnation) and Argyranthemum frutescens (Marguerite daisy). Analyses of transcripts involved in volatile production/emission revealed lower levels of the plasma-membrane transporter ABCG1 in the abaxial versus adaxial epidermis. Transient overexpression of ABCG1 enhanced emission from the abaxial epidermis to the level of the adaxial epidermis, suggesting its involvement in spatial emission patterns in the epidermal layers. Proboscis extension response experiments showed that differences in emission levels along the adaxial epidermis, that is, petal base versus rim, detected by GC-MS are also discernible by honeybees.
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Affiliation(s)
- Oded Skaliter
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yaarit Kitsberg
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Elad Sharon
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Elena Shklarman
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ekaterina Shor
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tania Masci
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yuling Yue
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yael Arien
- B. Triwaks Bee Research Center, Department of Entomology, Institute of Environmental Sciences, Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada, Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Sharoni Shafir
- B. Triwaks Bee Research Center, Department of Entomology, Institute of Environmental Sciences, Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Alexander Vainstein
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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Tunes P, Camargo MGG, Guimarães E. Floral UV Features of Plant Species From a Neotropical Savanna. Front Plant Sci 2021; 12:618028. [PMID: 34025689 PMCID: PMC8137824 DOI: 10.3389/fpls.2021.618028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Despite the wide interest in flower colours, only after the end of the nineteenth-century studies started to comprise floral UV reflection, which is invisible to humans but visible to the major groups of pollinators. Many flowers and inflorescences display colour patterns, an important signal for pollinators, promoted by the presence of at least two different colours within flowers or inflorescences, including colours in the UV waveband. For Neotropical savanna plant species, we characterised floral UV features using UV-photography and reflectance measurements. We tested (i) whether floral UV features were constrained by their shared ancestry, (ii) whether floral UV features were associated with pollinators, and (iii) whether floral UV features were associated with floral traits mediating these interactions, including floral resource, type of attraction unit and presence/absence of non-UV colour patterns. Of 80 plant species, ca. 70% were UV-patternless, most of them UV-absorbing. Approximately 30% presented one of three types of UV-patterns: bullseye, contrasting corolla markings oriented toward floral resources or contrasting reproductive structures, which were all considered as floral guides. Floral UV features were phylogenetically constrained and were associated with pollinators, floral resources and attraction unit, but not with non-UV colour patterns. UV-patternless flowers were associated with most of the pollination systems, while UV-patterned flowers were mainly associated with bee-pollination. UV-absorbing flowers comprised the only category with hawkmoth- and butterfly-pollinated flowers, and a high percentage of hummingbird-pollinated species. Nocturnal pollinated species were also commonly UV-absorbing, except for one UV-reflecting bat-pollinated species and one beetle-pollinated species with UV-reflecting stigmas. All types of floral UV features were associated with nectar; however, flowers with contrasting reproductive structures were mainly associated with pollen. There was an association between UV-absorbing species and the presence of inflorescences and intermediate attraction units. Our results evince that phylogenetic relatedness can constraint floral UV features' diversification, but combinations of evolutionary and ecological processes may be expected in this scenario.
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Affiliation(s)
- Priscila Tunes
- Laboratory of Ecology and Evolution of Plant-Animal Interactions, Postgraduate Program in Biological Sciences (Botany), Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | | | - Elza Guimarães
- Laboratory of Ecology and Evolution of Plant-Animal Interactions, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
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de Camargo MGG, Lunau K, Batalha MA, Brings S, de Brito VLG, Morellato LPC. How flower colour signals allure bees and hummingbirds: a community-level test of the bee avoidance hypothesis. New Phytol 2019; 222:1112-1122. [PMID: 30444536 DOI: 10.1111/nph.15594] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/08/2018] [Indexed: 05/07/2023]
Abstract
Colour signals are the main floral trait for plant-pollinator communication. Owing to visual specificities, flower visitors exert different selective pressures on flower colour signals of plant communities. Although they evolved to attract pollinators, matching their visual sensitivity and colour preferences, floral signals may also evolve to avoid less efficient pollinators and antagonistic flower visitors. We evaluated evidence for the bee avoidance hypothesis in a Neotropical community pollinated mainly by bees and hummingbirds, the campo rupestre. We analysed flower reflectance spectra, compared colour variables of bee-pollinated flowers (bee-flowers; 244 species) and hummingbird-pollinated flowers (hummingbird-flowers; 39 species), and looked for evidence of bee sensorial exclusion in hummingbird-flowers. Flowers were equally contrasting for hummingbirds. Hummingbird-flowers were less conspicuous to bees, reflecting mainly long wavelengths and avoiding red-blind visitors. Bee-flowers reflected more short wavelengths, were more conspicuous to bees (higher contrasts and spectral purity) than hummingbird-flowers and displayed floral guides more frequently, favouring flower attractiveness, discrimination and handling by bees. Along with no phylogenetic signal, the differences in colour signal strategies between bee- and hummingbird-flowers are the first evidence of the bee avoidance hypothesis at a community level and reinforce the role of pollinators as a selective pressure driving flower colour diversity.
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Affiliation(s)
- Maria Gabriela Gutierrez de Camargo
- Departamento de Botânica, Laboratório de Fenologia, Instituto de Biociências, UNESP-Universidade Estadual Paulista, 13506-900, Rio Claro, São Paulo, Brasil
| | - Klaus Lunau
- Department Biology, Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - Marco Antônio Batalha
- Department of Botany, Federal University of São Carlos, 13565-905, São Carlos, São Paulo, Brazil
| | - Sebastian Brings
- Department Biology, Institute of Sensory Ecology, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | | | - Leonor Patrícia Cerdeira Morellato
- Departamento de Botânica, Laboratório de Fenologia, Instituto de Biociências, UNESP-Universidade Estadual Paulista, 13506-900, Rio Claro, São Paulo, Brasil
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