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Bochynek T, Burd M. Pollination efficiency and the pollen-ovule ratio. THE NEW PHYTOLOGIST 2024; 243:1600-1609. [PMID: 38937955 DOI: 10.1111/nph.19929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 06/10/2024] [Indexed: 06/29/2024]
Abstract
Pollination presents a risky journey for pollen grains. Pollen loss is sometimes thought to favour greater pollen investment to compensate for the inefficiency of transport. Sex allocation theory, to the contrary, has consistently concluded that postdispersal loss should have no selective effect on investment in either sex function. But the intuitively appealing compensation idea continues to be raised despite the lack of theoretical endorsement. We address the theoretical issue with a model that directly represents pollen loss (and ovule loss through floral demise or loss of receptivity) as rate-dependent dynamical processes. These loss rates can be varied to examine the effect of pollination efficiency on optimal sex allocation. Pollen-ovule ratios follow from the sex allocation based on the resource costs of pollen and ovule production. This model confirms conventional findings that pollen loss should have essentially no effect on sexual resource allocation in large, panmictic populations. Pollen limitation of seed set does not alter this conclusion. These results force us to rethink the empirical association of pollination efficiency with low pollen-ovule ratios. This pattern could arise if efficient pollen transport commonly results in stigmatic deposition of cohorts of related pollen. Empirical evidence of correlated paternity supports this explanation.
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Affiliation(s)
- Thomas Bochynek
- Department of Physics, Emory University, Atlanta, GA, 30322, USA
| | - Martin Burd
- Indiana University Herbarium, East Tenth Street, Bloomington, IN, 47408, USA
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2
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Russell AL, Buchmann SL, Ascher JS, Wang Z, Kriebel R, Jolles DD, Orr MC, Hughes AC. Global patterns and drivers of buzzing bees and poricidal plants. Curr Biol 2024; 34:3055-3063.e5. [PMID: 38925116 DOI: 10.1016/j.cub.2024.05.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/06/2024] [Accepted: 05/29/2024] [Indexed: 06/28/2024]
Abstract
Foraging behavior frequently plays a major role in driving the geographic distribution of animals. Buzzing to extract protein-rich pollen from flowers is a key foraging behavior used by bee species across at least 83 genera (these genera comprise ∼58% of all bee species). Although buzzing is widely recognized to affect the ecology and evolution of bees and flowering plants (e.g., buzz-pollinated flowers), global patterns and drivers of buzzing bee biogeography remain unexplored. Here, we investigate the global species distribution patterns within each bee family and how patterns and drivers differ with respect to buzzing bee species. We found that both distributional patterns and drivers of richness typically differed for buzzing species compared with hotspots for all bee species and when grouped by family. A major predictor of the distribution, but not species richness overall for buzzing members of four of the five major bee families included in analyses (Andrenidae, Halictidae, Colletidae, and to a lesser extent, Apidae), was the richness of poricidal flowering plant species, which depend on buzzing bees for pollination. Because poricidal plant richness was highest in areas with low wind and high aridity, we discuss how global hotspots of buzzing bee biodiversity are likely influenced by both biogeographic factors and plant host availability. Although we explored global patterns with state-level data, higher-resolution work is needed to explore local-level drivers of patterns. From a global perspective, buzz-pollinated plants clearly play a greater role in the ecology and evolution of buzzing bees than previously predicted.
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Affiliation(s)
- Avery L Russell
- Department of Biology, Missouri State University, Springfield, MO 65897, USA.
| | - Stephen L Buchmann
- Department of Ecology and Evolutionary Biology and Department of Entomology, University of Arizona, Tucson, AZ, USA
| | - John S Ascher
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Zhiheng Wang
- College of Urban & Environmental Sciences, Peking University, 5 Yiheyuan Road, Beijing, China
| | - Ricardo Kriebel
- Department of Botany, Institute of Biodiversity Science and Sustainability, California Academy of Sciences, San Francisco, CA, USA
| | - Diana D Jolles
- Department of Biological Sciences, Plymouth State University, Plymouth, NH, USA
| | - Michael C Orr
- Entomologie, Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany; Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Alice C Hughes
- School of Biological Sciences, University of Hong Kong, Hong Kong, China.
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3
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Ballarin CS, Fontúrbel FE, Rech AR, Oliveira PE, Goés GA, Polizello DS, Oliveira PH, Hachuy-Filho L, Amorim FW. How many animal-pollinated angiosperms are nectar-producing? THE NEW PHYTOLOGIST 2024. [PMID: 38952269 DOI: 10.1111/nph.19940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/17/2024] [Indexed: 07/03/2024]
Abstract
The diversity of plant-pollinator interactions is grounded in floral resources, with nectar considered one of the main floral rewards plants produce for pollinators. However, a global evaluation of the number of animal-pollinated nectar-producing angiosperms and their distribution world-wide remains elusive. We compiled a thorough database encompassing 7621 plant species from 322 families to estimate the number and proportion of nectar-producing angiosperms reliant on animal pollination. Through extensive sampling of plant communities, we also explored the interplay between nectar production, floral resource diversity, latitudinal and elevational gradients, contemporary climate, and environmental characteristics. Roughly 223 308 animal-pollinated angiosperms are nectar-producing, accounting for 74.4% of biotic-pollinated species. Global distribution patterns of nectar-producing plants reveal a distinct trend along latitudinal and altitudinal gradients, with increased proportions of plants producing nectar in high latitudes and altitudes. Conversely, tropical communities in warm and moist climates exhibit greater floral resource diversity and a lower proportion of nectar-producing plants. These findings suggest that ecological trends driven by climate have fostered the diversification of floral resources in warmer and less seasonal climates, reducing the proportion of solely nectar-producing plants. Our study provides a baseline for understanding plant-pollinator relationships, plant diversification, and the distribution of plant traits.
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Affiliation(s)
- Caio S Ballarin
- Laboratório de Ecologia da Polinização e Interações - LEPI, Departamento de Biodiversidade e Bioestatística, Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (IBB - UNESP), Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, SP, CEP 18618-689, Brazil
- Programa de Pós-graduação em Biologia Vegetal, IBB - UNESP, Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, SP, CEP 18618-689, Brazil
| | - Francisco E Fontúrbel
- Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Av. Universidad 330, Valparaíso, CEP 2373223, Chile
- Millennium Nucleus of Patagonian Limit of Life (LiLi), Valdivia, CEP 5090000, Chile
| | - André R Rech
- Programas de Pós-Graduação em Biologia Animal, Estudos Rurais e Ciências Florestais, Faculdade Interdisciplinar em Humanidades, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, CEP 39100-000, Brazil
| | - Paulo E Oliveira
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, CEP 38405302, Brazil
| | - Guilherme Alcarás Goés
- Laboratório de Ecologia da Polinização e Interações - LEPI, Departamento de Biodiversidade e Bioestatística, Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (IBB - UNESP), Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, SP, CEP 18618-689, Brazil
- Laboratório de Restauração Florestal - LERF, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (UNESP), Botucatu, SP, CEP 18610-034, Brazil
| | - Diego S Polizello
- Laboratório de Ecologia da Polinização e Interações - LEPI, Departamento de Biodiversidade e Bioestatística, Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (IBB - UNESP), Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, SP, CEP 18618-689, Brazil
- Programa de Pós-graduação em Zoologia, IBB - UNESP, Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, São Paulo, CEP 18618-689, Brazil
| | - Pablo H Oliveira
- Laboratório de Ecologia da Polinização e Interações - LEPI, Departamento de Biodiversidade e Bioestatística, Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (IBB - UNESP), Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, SP, CEP 18618-689, Brazil
- Programa de Pós-graduação em Zoologia, IBB - UNESP, Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, São Paulo, CEP 18618-689, Brazil
| | - Leandro Hachuy-Filho
- Laboratório de Ecologia da Polinização e Interações - LEPI, Departamento de Biodiversidade e Bioestatística, Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (IBB - UNESP), Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, SP, CEP 18618-689, Brazil
- Programa de Pós-graduação em Zoologia, IBB - UNESP, Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, São Paulo, CEP 18618-689, Brazil
| | - Felipe W Amorim
- Laboratório de Ecologia da Polinização e Interações - LEPI, Departamento de Biodiversidade e Bioestatística, Instituto de Biociências, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (IBB - UNESP), Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, SP, CEP 18618-689, Brazil
- Programa de Pós-graduação em Biologia Vegetal, IBB - UNESP, Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, SP, CEP 18618-689, Brazil
- Programa de Pós-graduação em Zoologia, IBB - UNESP, Rua Prof. Dr Antonio Celso Wagner Zanin, Botucatu, São Paulo, CEP 18618-689, Brazil
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Ke Y, Zhang YB, Zhang FP, Yang D, Wang Q, Peng XR, Huang XY, Sher J, Zhang JL. Monocots and eudicots have more conservative flower water use strategies than basal angiosperms. PLANT BIOLOGY (STUTTGART, GERMANY) 2024; 26:621-632. [PMID: 38477557 DOI: 10.1111/plb.13637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/22/2024] [Indexed: 03/14/2024]
Abstract
Water balance is crucial for the growth and flowering of plants. However, the mechanisms by which flowers maintain water balance are poorly understood across different angiosperm branches. Here, we investigated 29 floral hydraulic and economic traits in 24 species from ANA grade, magnoliids, monocots, and eudicots. Our main objective was to compare differences in flower water use strategies between basal angiosperms (ANA grade and magnoliids) and derived group (monocots and eudicots). We found that basal angiosperms had richer petal stomatal density, higher pedicel hydraulic diameter, and flower mass per area, but lower pedicel vessel wall reinforcement and epidermal cell thickness compared to monocots and eudicots. We also observed significant trade-offs and coordination among different floral traits. Floral traits associated with reproduction, such as floral longevity and size, were strongly linked with physiological and anatomical traits. Our results systematically reveal the variation in flower economic and hydraulic traits from different angiosperm branches, deepening understanding of flower water use strategies among these plant taxa. We conclude that basal angiosperms maintain water balance with high water supply, whereas monocots and eudicots maintain a more conservative water balance.
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Affiliation(s)
- Y Ke
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Y-B Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - F-P Zhang
- College of Traditional Chinese Medicine, Yunnan University of Chinese Medicine, Kunming, Yunnan, China
| | - D Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - Q Wang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - X-R Peng
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - X-Y Huang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - J Sher
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - J-L Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
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5
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Wright EK, Timberlake TP, Baude M, Vaughan IP, Memmott J. Quantifying the production of plant pollen at the farm scale. THE NEW PHYTOLOGIST 2024; 242:2888-2899. [PMID: 38622779 DOI: 10.1111/nph.19763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Accepted: 03/27/2024] [Indexed: 04/17/2024]
Abstract
Plant pollen is rich in protein, sterols and lipids, providing crucial nutrition for many pollinators. However, we know very little about the quantity, quality and timing of pollen availability in real landscapes, limiting our ability to improve food supply for pollinators. We quantify the floral longevity and pollen production of a whole plant community for the first time, enabling us to calculate daily pollen availability. We combine these data with floral abundance and nectar measures from UK farmland to quantify pollen and nectar production at the landscape scale throughout the year. Pollen and nectar production were significantly correlated at the floral unit, and landscape level. The species providing the highest quantity of pollen on farmland were Salix spp. (38%), Filipendula ulmaria (14%), Rubus fruticosus (10%) and Taraxacum officinale (9%). Hedgerows were the most pollen-rich habitats, but permanent pasture provided the majority of pollen at the landscape scale, because of its large area. Pollen and nectar were closely associated in their phenology, with both peaking in late April, before declining steeply in June and remaining low throughout the year. Our data provide a starting point for including pollen in floral resource assessments and ensuring the nutritional requirements of pollinators are met in farmland landscapes.
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Affiliation(s)
- Ellen K Wright
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
- Cabot Institute, University of Bristol, Royal Fort House, Bristol, BS8 1UH, UK
| | - Thomas P Timberlake
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Mathilde Baude
- Université d'Orléans, Château de la Source, BP 6749, Orléans Cedex 2, 45067, France
- Institut d'Ecologie et des Sciences de l'Environnement (iEES-Paris), Sorbonne Université, UPEC, Université Paris Cité, CNRS, IRD, INRAE, Paris, 75005, France
| | - Ian P Vaughan
- Cardiff School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Jane Memmott
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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6
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Stephens RE, Gallagher RV, Méndez M, Sauquet H. Zygomorphic flowers last longer: the evolution of floral symmetry and floral longevity. Biol Lett 2024; 20:20240082. [PMID: 38889773 DOI: 10.1098/rsbl.2024.0082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 05/07/2024] [Indexed: 06/20/2024] Open
Abstract
Floral longevity, the length of time a flower remains open and functional, is a phylogenetically conserved trait that balances floral costs against the rate at which flowers are pollinated. Floral symmetry has long been considered a key trait in floral evolution. Although zygomorphic (bilaterally symmetric) flowers typically receive fewer floral visitors than actinomorphic (radially symmetric) flowers, it is yet to be determined whether this could be associated with longer floral longevity. Using newly collected field data combined with data from the literature on 1452 species in 168 families, we assess whether floral longevity covaries with floral symmetry in a phylogenetic framework. We find that zygomorphic flowers last on average 1.1 days longer than actinomorphic flowers, a 26.5% increase in longevity, with considerable variation across both groups. Our results provide a basis to discuss the ecological and evolutionary costs of zygomorphy for plants. Despite these costs, zygomorphy has evolved numerous times throughout angiosperm history, and we discuss which rewards may outweigh the costs of slower pollination in zygomorphic flowers.
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Affiliation(s)
- R E Stephens
- School of Natural Sciences, Macquarie University , Ryde, New South Wales, Australia
- National Herbarium of NSW, Botanic Gardens of Sydney , Mount Annan, New South Wales, Australia
| | - R V Gallagher
- School of Natural Sciences, Macquarie University , Ryde, New South Wales, Australia
- Hawkesbury Institute for the Environment, Western Sydney University , Richmond, New South Wales, Australia
| | - M Méndez
- Area of Biodiversity and Conservation, Universidad Rey Juan Carlos , Madrid, Spain
| | - H Sauquet
- National Herbarium of NSW, Botanic Gardens of Sydney , Mount Annan, New South Wales, Australia
- Evolution & Ecology Research Centre, University of New South Wales , Sydney, New South Wales, Australia
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7
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Matallana-Puerto CA, Duarte MO, Aguilar Fachin D, Poloni Guilherme C, Oliveira PE, Cardoso JCF. First evidence of late-acting self-incompatibility in the Aristolochiaceae. PLANT BIOLOGY (STUTTGART, GERMANY) 2024; 26:612-620. [PMID: 38634401 DOI: 10.1111/plb.13649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 03/25/2024] [Indexed: 04/19/2024]
Abstract
Most Aristolochiaceae species studied so far are from temperate regions, bearing self-compatible protogynous trap flowers. Although self-incompatibility has been suggested for tropical species, the causes of self-sterility in this family remain unknown. To fill this gap, we studied the pollination of the tropical Aristolochia esperanzae, including the physical and physiological anti-selfing mechanisms. Floral visitors trapped inside flowers were collected to determine the pollinators. Protogyny was characterized by observing the temporal expression of sexual phases and stigmatic receptivity tests. The breeding system was investigated using hand-pollination treatments. Pollen tube growth was observed using epifluorescence to identify the self-incompatibility mechanism. Flies were the most frequent visitors found inside A. esperanzae trap flowers, with individuals from the family Ulidiidae being potential pollinators since they carried pollen. The characteristic flower odour and presence of larvae indicate that A. esperanzae deceives flies through oviposition-site mimicry. Although this species showed incomplete protogyny, stigmatic receptivity decreased during the male phase, avoiding self-pollination. Fruits developed only after cross- and open pollination, indicating that the population is non-autonomous, non-apomictic, and self-sterile. This occurred through a delay in the growth of geitonogamous pollen tubes to the ovary and lower ovule penetration, indicating a late-acting self-incompatibility mechanism. Our findings expand the number of families in which late-acting self-incompatibility has been reported, demonstrating that it is more widespread than previously thought, especially when considering less-studied tropical species among the basal angiosperms.
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Affiliation(s)
- C A Matallana-Puerto
- Programa de Pós-Graduação em Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | - M O Duarte
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - D Aguilar Fachin
- Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Campus Samambaia, Goiânia, Goiás, Brazil
| | - C Poloni Guilherme
- Laboratório de Evolução e Morfologia de Diptera, Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - P E Oliveira
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - J C F Cardoso
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
- Departamento de Biodiversidade, Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil
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8
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Song B, Chen J, Lev-Yadun S, Niu Y, Gao Y, Ma R, Armbruster WS, Sun H. Multifunctionality of angiosperm floral bracts: a review. Biol Rev Camb Philos Soc 2024; 99:1100-1120. [PMID: 38291834 DOI: 10.1111/brv.13060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/02/2024] [Accepted: 01/22/2024] [Indexed: 02/01/2024]
Abstract
Floral bracts (bracteoles, cataphylls) are leaf-like organs that subtend flowers or inflorescences but are of non-floral origin; they occur in a wide diversity of species, representing multiple independent origins, and exhibit great variation in form and function. Although much attention has been paid to bracts over the past 150 years, our understanding of their adaptive significance remains remarkably incomplete. This is because most studies of bract function and evolution focus on only one or a few selective factors. It is widely recognised that bracts experience selection mediated by pollinators, particularly for enhancing pollinator attraction through strong visual, olfactory, or echo-acoustic contrast with the background and through signalling the presence of pollinator rewards, either honestly (providing rewards for pollinators), or deceptively (attraction without reward or even trapping pollinators). However, studies in recent decades have demonstrated that bract evolution is also affected by agents other than pollinators. Bracts can protect flowers, fruits, or seeds from herbivores by displaying warning signals, camouflaging conspicuous reproductive organs, or by providing physical barriers or toxic chemicals. Reviews of published studies show that bracts can also promote seed dispersal and ameliorate the effects of abiotic stressors, such as low temperature, strong ultraviolet radiation, heavy rain, drought, and/or mechanical abrasion, on reproductive organs or for the plants' pollinators. In addition, green bracts and greening of colourful bracts after pollination promote photosynthetic activity, providing substantial carbon (photosynthates) for fruit or seed development, especially late in a plant's life cycle or season, when leaves have started to senesce. A further layer of complexity derives from the fact that the agents of selection driving the evolution of bracts vary between species and even between different developmental stages within a species, and selection by one agent can be reinforced or opposed by other agents. In summary, our survey of the literature reveals that bracts are multifunctional and subject to multiple agents of selection. To understand fully the functional and evolutionary significance of bracts, it is necessary to consider multiple selection agents throughout the life of the plant, using integrative approaches to data collection and analysis.
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Affiliation(s)
- Bo Song
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, China
| | - Jiaqi Chen
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, China
- School of Life Sciences, Yunnan University, Huannan Road, East of University Town, Chenggong New Area, Kunming, 650500, China
| | - Simcha Lev-Yadun
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa at Oranim, Kiryat Tiv'on, 36006, Israel
| | - Yang Niu
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, China
| | - Yongqian Gao
- Yunnan Forestry Technological College, 1 Jindian, Kunming, 650224, China
| | - Rong Ma
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, China
| | - W Scott Armbruster
- School of Biological Sciences, University of Portsmouth, King Henry Building, King Henry I Street, Portsmouth, PO1 2DY, UK
- Institute of Arctic Biology, University of Alaska, PO Box 757000, Fairbanks, AK, 99775, USA
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, China
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9
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Cun S, Zhang C, Chen J, Qian L, Sun H, Song B. Effects of UV-B radiation on pollen germination and tube growth: A global meta-analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:170097. [PMID: 38224898 DOI: 10.1016/j.scitotenv.2024.170097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/07/2024] [Accepted: 01/09/2024] [Indexed: 01/17/2024]
Abstract
Despite widespread recognition of pollen's potential sensitivity to ultraviolet-B (UV-B) radiation (280-315 nm), there remains ongoing debate surrounding the extent and mechanisms of this effect. In this study, using published data on pollen germination and tube growth including 377 pair-wise comparisons from 77 species in 30 families, we present the first global quantification of the effects of UV-B radiation on pollen germination and tube growth, along with its underlying mechanisms. Our results showed a substantial reduction in both pollen germination and tube growth in response to UV-B radiation, affecting 90.9 % and 84.2 % of species, respectively. Notably, these reductions exhibited phylogenetic constraints, highlighting the role of evolutionary history in shaping the sensitivity of pollen germination and tube growth to UV-B radiation. A negative correlation between elevation and the sensitivity of pollen tube growth was detected, suggesting that pollens from plants at higher elevations exhibit greater resistance to UV-B radiation. Our investigation also revealed that the effects of UV-B radiation on pollen germination and tube growth were influenced by a range of abiotic and biotic factors. Nevertheless, the intensity and duration of UV-B radiation exposure exhibited the highest explanatory power for the effects on both pollen germination and tube growth. This suggests that the responses of pollens to UV-B radiation are profoundly influenced by its dose, a critical consideration within the context of global change. In conclusion, our study provides valuable insights into the diverse responses of pollen germination and tube growth to UV-B radiation, highlighting the environment and species-dependent nature of pollen's susceptibility to UV-B radiation, with substantial implications for our understanding of the ecological and agricultural consequences of ongoing changes in UV-B radiation.
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Affiliation(s)
- Shuang Cun
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chan Zhang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Jiaqi Chen
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; School of Life Sciences, Yunnan University, Kunming 650504, China
| | - Lishen Qian
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
| | - Bo Song
- Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
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Ma R, Xu Q, Gao Y, Peng D, Sun H, Song B. Patterns and drivers of plant sexual systems in the dry-hot valley region of southwestern China. PLANT DIVERSITY 2024; 46:158-168. [PMID: 38807913 PMCID: PMC11128841 DOI: 10.1016/j.pld.2023.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 07/29/2023] [Accepted: 07/31/2023] [Indexed: 05/30/2024]
Abstract
Sexual systems play important roles in angiosperm evolution and exhibit substantial variations among different floras. Thus, studying their evolution in a whole flora is crucial for understanding the formation and maintenance of plant biodiversity and predicting its responses to environmental change. In this study, we determined the patterns of plant sexual systems and their associations with geographic elements and various life-history traits in dry-hot valley region of southwestern China, an extremely vulnerable ecosystem. Of the 3166 angiosperm species recorded in this area, 74.5% were hermaphroditic, 13.5% were monoecious and 12% were dioecious, showing a high incidence of diclinous species. Diclinous species were strongly associated with tropical elements, whereas hermaphroditic species were strongly associated with temperate and cosmopolitan elements. We also found that hermaphroditism was strongly associated with showy floral displays, specialist entomophily, dry fruits and herbaceous plants. Dioecy was strongly associated with inconspicuous, pale-colored flowers, generalist entomophily, fleshy fruits, and woody plants, whereas monoecy was strongly associated with inconspicuous, pale-colored flowers, anemophily, dry fruits, and herbaceous plants. In addition, hermaphroditic species with generalist entomophily tended to flower in the dry season, whereas diclinous species with specialist entomophily tended to flower in the rainy season. However, independent of sexual systems, plants that produce dry fruits tended to flower in the rainy season and set fruits in the dry season, but the opposite pattern was found for fleshy fruit-producing plants. Our results suggest that in the dry-hot valleys, plant sexual systems are associated with geographic elements as well as various life-history traits that are sensitive to environmental change.
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Affiliation(s)
- Rong Ma
- State Key Laboratory of Plant Diversity and Specialty Crops/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
| | - Qi Xu
- State Key Laboratory of Plant Diversity and Specialty Crops/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Yongqian Gao
- Yunnan Forestry Technological College, Kunming 650224, China
| | - Deli Peng
- School of Life Science/Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan Normal University, Kunming 650500, Yunnan, China
| | - Hang Sun
- State Key Laboratory of Plant Diversity and Specialty Crops/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Bo Song
- State Key Laboratory of Plant Diversity and Specialty Crops/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
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11
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Nepal S, Trunschke J, Ren ZX, Burgess KS, Wang H. Flowering phenology differs among wet and dry sub-alpine meadows in southwestern China. AOB PLANTS 2024; 16:plae002. [PMID: 38298756 PMCID: PMC10829081 DOI: 10.1093/aobpla/plae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/16/2024] [Indexed: 02/02/2024]
Abstract
The effect of floral traits, floral rewards and plant water availability on plant-pollinator interactions are well-documented; however, empirical evidence of their impact on flowering phenology in high-elevation meadows remains scarce. In this study, we assessed three levels of flowering phenology, i.e. population-, individual- and flower-level (floral longevity), in two nearby but contrasting (wet versus dry) sub-alpine meadows on Yulong Snow Mountain, southwestern China. We also measured a series of floral traits (pollen number, ovule number, and the ratio of pollen to ovule number per flower, i.e. pollen:ovule ratio [P/O]) and floral rewards (nectar availability and pollen presentation) as plausible additional sources of variation for each phenological level. Floral longevity in the wet meadow was significantly longer than that for the dry meadow, whereas population- and individual-flowering duration were significantly shorter. Our results showed a significant positive relationship between flowering phenology with pollen number and P/O per flower; there was no relationship with ovule number per flower. Further, we found a significant effect of flowering phenology on nectar availability and pollen presentation. Our findings suggest that shorter floral longevity in dry habitats compared to wet might be due to water-dependent maintenance costs of flowers, where the population- and individual-level flowering phenology may be less affected by habitats. Our study shows how different levels of flowering phenology underscore the plausible effects of contrasting habitats on reproductive success.
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Affiliation(s)
- Shristhi Nepal
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, China
- University of Chinese Academy of Sciences, No.1 Yanqihu East Rd, Huairou District, Beijing 101408, China
| | - Judith Trunschke
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, China
- Nature Conservation and Landscape Ecology, Faculty of Environment and Natural Resources, University of Freiburg, Tennenbacher Str., 479106 Freiburg, Germany
| | - Zong-Xin Ren
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, China
| | - Kevin S Burgess
- Department of Biomedical Sciences, Mercer University School of Medicine, Columbus, GA 31901, USA
| | - Hong Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, China
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12
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Ke Y, Zhang FP, Zhang YB, Li W, Wang Q, Yang D, Zhang JL, Cao KF. Convergent relationships between flower economics and hydraulic traits across aquatic and terrestrial herbaceous plants. PLANT DIVERSITY 2023; 45:601-610. [PMID: 37936818 PMCID: PMC10625894 DOI: 10.1016/j.pld.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/14/2023] [Accepted: 01/17/2023] [Indexed: 11/09/2023]
Abstract
Maintaining open flowers is critical for successful pollination and depends on long-term water and carbon balance. Yet the relationship between how flower hydraulic traits are coordinated in different habitats is poorly understood. Here, we hypothesize that the coordination and trade-offs between floral hydraulics and economics traits are independent of environmental conditions. To test this hypothesis, we investigated a total of 27 flower economics and hydraulic traits in six aquatic and six terrestrial herbaceous species grown in a tropical botanical garden. We found that although there were a few significant differences, most flower hydraulics and economics traits did not differ significantly between aquatic and terrestrial herbaceous plants. Both flower mass per area and floral longevity were significantly positively correlated with the time required for drying full-hydrated flowers to 70% relative water content. Flower dry matter content was strongly and positively related to drought tolerance of the flowers as indicated by flower water potential at the turgor loss point. In addition, there was a trade-off between hydraulic efficiency and the construction cost of a flower across species. Our results show that flowers of aquatic and terrestrial plants follow the same economics spectrum pattern. These results suggest a convergent flower economics design across terrestrial and aquatic plants, providing new insights into the mechanisms by which floral organs adapt to aquatic and terrestrial habitats.
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Affiliation(s)
- Yan Ke
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Feng-Ping Zhang
- College of Traditional Chinese Medicine, Yunnan University of Chinese Medicine, Kunming, Yunnan 650500, China
| | - Yun-Bing Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Li
- School of Biological and Chemical Sciences, Puer University, Puer, Yunnan 665000, China
| | - Qin Wang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Da Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Jiao-Lin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Kun-Fang Cao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi University, Daxuedong Road 100, Nanning, Guangxi 530004, China
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13
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Roddy AB, Guilliams CM, Fine PVA, Mambelli S, Dawson TE, Simonin KA. Flowers are leakier than leaves but cheaper to build. THE NEW PHYTOLOGIST 2023; 239:2076-2082. [PMID: 37366068 DOI: 10.1111/nph.19104] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 05/29/2023] [Indexed: 06/28/2023]
Affiliation(s)
- Adam B Roddy
- Institute of Environment, Department of Biological Sciences, Florida International University, Miami, 33199, FL, USA
| | | | - Paul V A Fine
- Department of Integrative Biology, University of California-Berkeley, Berkeley, 94720, CA, USA
| | - Stefania Mambelli
- Department of Integrative Biology, University of California-Berkeley, Berkeley, 94720, CA, USA
| | - Todd E Dawson
- Department of Integrative Biology, University of California-Berkeley, Berkeley, 94720, CA, USA
| | - Kevin A Simonin
- Department of Biology, San Francisco State University, San Francisco, 94132, CA, USA
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Xu YW, Sun L, Ma R, Gao YQ, Sun H, Song B. Does pollinator dependence decrease along elevational gradients? PLANT DIVERSITY 2023; 45:446-455. [PMID: 37601546 PMCID: PMC10435910 DOI: 10.1016/j.pld.2023.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/15/2023] [Accepted: 03/19/2023] [Indexed: 08/22/2023]
Abstract
Plants have long been thought to be less dependent on pollinators for seed production at higher elevations due to adverse pollination environments. However, recent research has yet to consistently support the generality of this expectation. In this study, we asked whether pollinator dependence decreases along an elevational gradient and how it varies with various reproductive traits. To answer these questions, we quantified pollinator-plant associations and various reproductive traits for 112 flowering plants spanning a large elevational gradient (990-4260 m a.s.l.) in the Qinghai-Tibet Plateau. We found that flowering plants in the Qinghai-Tibet Plateau region are highly dependent on pollinators for seed production (76.2% of seed production was contributed by animal pollinators and 44.6% of plants would produce no seed without pollinator visitation). Contrary to our expectation, there was no significant elevational gradient in pollinator dependence index. Although the pollinator dependence index was not significantly correlated with pollen limitation, flower size, floral longevity, or reward type, it was correlated with compatibility status and flowering time. These findings indicate that pollinator dependence does not decrease along an elevational gradient in the Qinghai-Tibet Plateau. Our study also highlights the severe vulnerability of flowering plant seed production to pollinator declines under global change in the Qinghai-Tibet Plateau region, particularly for early-flowering or self-incompatible plants growing at higher elevations (e.g., subnival belt).
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Affiliation(s)
- Yue-Wen Xu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Lu Sun
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Rong Ma
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
| | - Yong-Qian Gao
- Yunnan Forestry Technological College, Kunming 650224, China
| | - Hang Sun
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Bo Song
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia/Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
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15
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da Cunha NL, Aizen MA. Pollen production per flower increases with floral display size across animal-pollinated flowering plants. AMERICAN JOURNAL OF BOTANY 2023:e16180. [PMID: 37243835 DOI: 10.1002/ajb2.16180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 05/29/2023]
Abstract
PREMISE The number of open flowers on a plant (i.e., floral display size) can influence plant fitness by increasing pollinator attraction. However, diminishing marginal fitness returns with increasing floral display are expected as pollinators tend to visit more flowers per plant consecutively. An extended flower visitation sequence increases the fraction of ovules disabled by self-pollination (ovule discounting) and reduces the fraction of a plant's own pollen that is exported to sire seeds in other plants (pollen discounting). Hermaphroditic species with a genetic system that prevents self-fertilization (self-incompatibility) would avoid ovule discounting and its fitness cost, whereas species without such a genetically based barrier would not. Contrarily, pollen discounting would be an unavoidable consequence of a large floral display irrespective of selfing barriers. Nevertheless, the increasing fitness costs of ovule and pollen discounting could be offset by respectively increasing ovule and pollen production per flower. METHODS We compiled data on floral display size and pollen and ovule production per flower for 1241 animal-pollinated, hermaphroditic angiosperm species, including data on the compatibility system for 779 species. We used phylogenetic general linear mixed models to assess the relations of pollen and ovule production to floral display size. RESULTS Our findings provide evidence of increasing pollen production, but not of ovule production, with increasing display size irrespective of compatibility system and even after accounting for potentially confounding effects like flower size and growth form. CONCLUSIONS Our comparative study supports the pollen-discount expectation of an adaptive link between per-flower pollen production and floral display across animal-pollinated angiosperms.
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Affiliation(s)
- Nicolay Leme da Cunha
- Grupo de Ecología de la Polinización, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA), Universidad Nacional del Comahue-CONICET, 8400, San Carlos de Bariloche, Argentina
| | - Marcelo Adrián Aizen
- Grupo de Ecología de la Polinización, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA), Universidad Nacional del Comahue-CONICET, 8400, San Carlos de Bariloche, Argentina
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