Mechanisms underpinning the onset of seed coat impermeability and dormancy-break in Astragalus adsurgens
Abstract Impermeable seed coats, i.e. physical dormancy (PY) influence the germination ecology of plants from 18 angiosperm families. Astragalus adsurgens (Fabaceae; Papilinoidaae) is a perennial plant widespread in temperate regions that is thought to produce both permeable and impermeable seeds. W...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2019-07-01
|
| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-019-46158-z |
| _version_ | 1818344922666762240 |
|---|---|
| author | Ganesh K. Jaganathan Jiajin Li Matthew Biddick Kang Han Danping Song Yashu Yang Yingying Han Baolin Liu |
| author_facet | Ganesh K. Jaganathan Jiajin Li Matthew Biddick Kang Han Danping Song Yashu Yang Yingying Han Baolin Liu |
| author_sort | Ganesh K. Jaganathan |
| collection | DOAJ |
| description | Abstract Impermeable seed coats, i.e. physical dormancy (PY) influence the germination ecology of plants from 18 angiosperm families. Astragalus adsurgens (Fabaceae; Papilinoidaae) is a perennial plant widespread in temperate regions that is thought to produce both permeable and impermeable seeds. Why seeds vary in the permeability of their coat, in addition to the mechanisms by which impermeable seeds break dormancy, are not completely understood. However, seeds are often consumed by herbivores; a phenomenon that might facilitate the germination of impermeable seeds. Here, we tested whether: (1) moisture content plays a significant role in the onset of seed coat impermeability (and therefore PY) at similar ranges reported for species from tropical ecosystems; and (2) the presence of impermeable coats offer any benefits for seed survival when consumed by animals. We tested these hypotheses using A. adsurgens seeds collected from Inner Mongolia, China. Freshly collected seeds with a moisture content of 9.7% were permeable to water and therefore not physically dormant. However, seeds became impermeable when dried below a threshold of 6.5% moisture content. Treating impermeable seeds with hydrochloric acid effectively broke dormancy. Scanning electron microscope (SEM) revealed that HCl treated seeds had a narrow opening in the hilum and extra-hilar regions, through which water entered. Seeds with impermeable coats survived significantly better than permeable seeds when consumed by cows. Irrespective of coat permeability, most seeds were egested between 12 and 24 h. In seeds that maintained dormancy after gut passage, this was broken by additional acid scarification. Overall results suggest that: (1) seed coat impermeability is induced by reduced moisture content; (2) imbibition primarily occurs at the hilum and extra-hilar region; and (3) impermeable seeds may benefit from endozoochory. |
| first_indexed | 2024-12-13T16:54:11Z |
| format | Article |
| id | doaj.art-5f10b36019994587a71a2c722899a5c3 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-13T16:54:11Z |
| publishDate | 2019-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-5f10b36019994587a71a2c722899a5c32022-12-21T23:37:58ZengNature PortfolioScientific Reports2045-23222019-07-019111010.1038/s41598-019-46158-zMechanisms underpinning the onset of seed coat impermeability and dormancy-break in Astragalus adsurgensGanesh K. Jaganathan0Jiajin Li1Matthew Biddick2Kang Han3Danping Song4Yashu Yang5Yingying Han6Baolin Liu7Institute of Biothermal Technology, University of Shanghai for Science and TechnologyInstitute of Biothermal Technology, University of Shanghai for Science and TechnologySchool of Biological Sciences, Victoria University of WellingtonInstitute of Biothermal Technology, University of Shanghai for Science and TechnologyInstitute of Biothermal Technology, University of Shanghai for Science and TechnologyInstitute of Biothermal Technology, University of Shanghai for Science and TechnologyInstitute of Biothermal Technology, University of Shanghai for Science and TechnologyInstitute of Biothermal Technology, University of Shanghai for Science and TechnologyAbstract Impermeable seed coats, i.e. physical dormancy (PY) influence the germination ecology of plants from 18 angiosperm families. Astragalus adsurgens (Fabaceae; Papilinoidaae) is a perennial plant widespread in temperate regions that is thought to produce both permeable and impermeable seeds. Why seeds vary in the permeability of their coat, in addition to the mechanisms by which impermeable seeds break dormancy, are not completely understood. However, seeds are often consumed by herbivores; a phenomenon that might facilitate the germination of impermeable seeds. Here, we tested whether: (1) moisture content plays a significant role in the onset of seed coat impermeability (and therefore PY) at similar ranges reported for species from tropical ecosystems; and (2) the presence of impermeable coats offer any benefits for seed survival when consumed by animals. We tested these hypotheses using A. adsurgens seeds collected from Inner Mongolia, China. Freshly collected seeds with a moisture content of 9.7% were permeable to water and therefore not physically dormant. However, seeds became impermeable when dried below a threshold of 6.5% moisture content. Treating impermeable seeds with hydrochloric acid effectively broke dormancy. Scanning electron microscope (SEM) revealed that HCl treated seeds had a narrow opening in the hilum and extra-hilar regions, through which water entered. Seeds with impermeable coats survived significantly better than permeable seeds when consumed by cows. Irrespective of coat permeability, most seeds were egested between 12 and 24 h. In seeds that maintained dormancy after gut passage, this was broken by additional acid scarification. Overall results suggest that: (1) seed coat impermeability is induced by reduced moisture content; (2) imbibition primarily occurs at the hilum and extra-hilar region; and (3) impermeable seeds may benefit from endozoochory.https://doi.org/10.1038/s41598-019-46158-z |
| spellingShingle | Ganesh K. Jaganathan Jiajin Li Matthew Biddick Kang Han Danping Song Yashu Yang Yingying Han Baolin Liu Mechanisms underpinning the onset of seed coat impermeability and dormancy-break in Astragalus adsurgens Scientific Reports |
| title | Mechanisms underpinning the onset of seed coat impermeability and dormancy-break in Astragalus adsurgens |
| title_full | Mechanisms underpinning the onset of seed coat impermeability and dormancy-break in Astragalus adsurgens |
| title_fullStr | Mechanisms underpinning the onset of seed coat impermeability and dormancy-break in Astragalus adsurgens |
| title_full_unstemmed | Mechanisms underpinning the onset of seed coat impermeability and dormancy-break in Astragalus adsurgens |
| title_short | Mechanisms underpinning the onset of seed coat impermeability and dormancy-break in Astragalus adsurgens |
| title_sort | mechanisms underpinning the onset of seed coat impermeability and dormancy break in astragalus adsurgens |
| url | https://doi.org/10.1038/s41598-019-46158-z |
| work_keys_str_mv | AT ganeshkjaganathan mechanismsunderpinningtheonsetofseedcoatimpermeabilityanddormancybreakinastragalusadsurgens AT jiajinli mechanismsunderpinningtheonsetofseedcoatimpermeabilityanddormancybreakinastragalusadsurgens AT matthewbiddick mechanismsunderpinningtheonsetofseedcoatimpermeabilityanddormancybreakinastragalusadsurgens AT kanghan mechanismsunderpinningtheonsetofseedcoatimpermeabilityanddormancybreakinastragalusadsurgens AT danpingsong mechanismsunderpinningtheonsetofseedcoatimpermeabilityanddormancybreakinastragalusadsurgens AT yashuyang mechanismsunderpinningtheonsetofseedcoatimpermeabilityanddormancybreakinastragalusadsurgens AT yingyinghan mechanismsunderpinningtheonsetofseedcoatimpermeabilityanddormancybreakinastragalusadsurgens AT baolinliu mechanismsunderpinningtheonsetofseedcoatimpermeabilityanddormancybreakinastragalusadsurgens |