Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentation
IntroductionPollen is usually presented by the anthers after maturity. However, in some plants, pollen is presented to pollinators on other floral structures (other than the anthers), or via particular expulsion mechanisms, resulting in secondary pollen presentation. The unusual petal morphology in...
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Frontiers Media S.A.
2025-01-01
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| Series: | Frontiers in Plant Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fpls.2025.1525022/full |
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| author | Fang Ma Fang Ma Qian Zhao Xing Tian Yao-lei Fu Wen-zhe Liu |
| author_facet | Fang Ma Fang Ma Qian Zhao Xing Tian Yao-lei Fu Wen-zhe Liu |
| author_sort | Fang Ma |
| collection | DOAJ |
| description | IntroductionPollen is usually presented by the anthers after maturity. However, in some plants, pollen is presented to pollinators on other floral structures (other than the anthers), or via particular expulsion mechanisms, resulting in secondary pollen presentation. The unusual petal morphology in Berchemia mediates pollen presentation, characterised by a combination of secondary pollen presentation and primary pollen presentation. However, the function, the role in reproduction, and the evolutionary significance of the unusual petals remain unclear.MethodsIn this study, we took Berchemia flavescens and Berchemia polyphylla var. leioclada as examples, and used field observations, semi-thin sections technology, scanning electron microscopy, and pollination ecology detection methods to explore the unique pollen presentation strategies, petal functions, and reproductive strategies in Berchemia.ResultsThis is a unique pollen presentation process mediated by petals. In the advanced bud stage, petals curl inward, enclosing the stamens. Following anther dehiscence, pollen is released into the petal tube, where the filament and cone-shaped anthers act as pistons, extruding pollen or pollen clumps through gaps at the petal tube apex (secondary pollen presentation). Subsequently, as the anthers emerge from the petal tube, residual pollen is directly presented to pollinators (primary pollen presentation).DiscussionIn Berchemia, the petals enclosing the stamens, effectively shield the pollen from extreme environmental conditions. The petal-stamen complex slow movement (first centrifugal, later centripetal) and pollen presentation in Berchemia suggest a unique reproductive strategy. This mechanism promotes outcrossing, minimizing interference between the pistil and stamens, and offers reproductive assurance by delayed self-pollination. |
| format | Article |
| id | doaj-art-bfa12801d6cf4dc2b67aaa8e5167c106 |
| institution | Kabale University |
| issn | 1664-462X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Plant Science |
| spelling | doaj-art-bfa12801d6cf4dc2b67aaa8e5167c1062025-01-29T06:45:44ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2025-01-011610.3389/fpls.2025.15250221525022Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentationFang Ma0Fang Ma1Qian Zhao2Xing Tian3Yao-lei Fu4Wen-zhe Liu5School of Life Science, Northwest University, Xi’an, ChinaInstitute of Ethnic Preparatory Education, Ningxia University, Yinchuan, ChinaSchool of Life Science, Northwest University, Xi’an, ChinaSchool of Life Science, Northwest University, Xi’an, ChinaSchool of Life Science, Northwest University, Xi’an, ChinaSchool of Life Science, Northwest University, Xi’an, ChinaIntroductionPollen is usually presented by the anthers after maturity. However, in some plants, pollen is presented to pollinators on other floral structures (other than the anthers), or via particular expulsion mechanisms, resulting in secondary pollen presentation. The unusual petal morphology in Berchemia mediates pollen presentation, characterised by a combination of secondary pollen presentation and primary pollen presentation. However, the function, the role in reproduction, and the evolutionary significance of the unusual petals remain unclear.MethodsIn this study, we took Berchemia flavescens and Berchemia polyphylla var. leioclada as examples, and used field observations, semi-thin sections technology, scanning electron microscopy, and pollination ecology detection methods to explore the unique pollen presentation strategies, petal functions, and reproductive strategies in Berchemia.ResultsThis is a unique pollen presentation process mediated by petals. In the advanced bud stage, petals curl inward, enclosing the stamens. Following anther dehiscence, pollen is released into the petal tube, where the filament and cone-shaped anthers act as pistons, extruding pollen or pollen clumps through gaps at the petal tube apex (secondary pollen presentation). Subsequently, as the anthers emerge from the petal tube, residual pollen is directly presented to pollinators (primary pollen presentation).DiscussionIn Berchemia, the petals enclosing the stamens, effectively shield the pollen from extreme environmental conditions. The petal-stamen complex slow movement (first centrifugal, later centripetal) and pollen presentation in Berchemia suggest a unique reproductive strategy. This mechanism promotes outcrossing, minimizing interference between the pistil and stamens, and offers reproductive assurance by delayed self-pollination.https://www.frontiersin.org/articles/10.3389/fpls.2025.1525022/fullBerchemiasecondary pollen presentationpetal-stamen complexsexual interferencedelayed selfingreproduction assurance |
| spellingShingle | Fang Ma Fang Ma Qian Zhao Xing Tian Yao-lei Fu Wen-zhe Liu Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentation Frontiers in Plant Science Berchemia secondary pollen presentation petal-stamen complex sexual interference delayed selfing reproduction assurance |
| title | Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentation |
| title_full | Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentation |
| title_fullStr | Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentation |
| title_full_unstemmed | Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentation |
| title_short | Stamens enclosed by petals in Berchemia (Rhamnaceae): a unique mechanism for pollen presentation |
| title_sort | stamens enclosed by petals in berchemia rhamnaceae a unique mechanism for pollen presentation |
| topic | Berchemia secondary pollen presentation petal-stamen complex sexual interference delayed selfing reproduction assurance |
| url | https://www.frontiersin.org/articles/10.3389/fpls.2025.1525022/full |
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