Seed Germination Ecology of <i>Sonchus asper</i> and <i>Sonchus oleraceus</i> in Queensland Australia
<i>Sonchus asper</i> and <i>S. oleraceus</i> are among the most problematic broadleaf weeds in eastern cropping systems of Australia. This study investigated the seed germination ecology of <i>S. asper</i> and <i>S. oleraceus</i>. The study hypothesize...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Plants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2223-7747/13/23/3451 |
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| Summary: | <i>Sonchus asper</i> and <i>S. oleraceus</i> are among the most problematic broadleaf weeds in eastern cropping systems of Australia. This study investigated the seed germination ecology of <i>S. asper</i> and <i>S. oleraceus</i>. The study hypothesized that <i>S. asper</i> may have greater ecological advantages under adverse environmental conditions compared to <i>S. oleraceus</i>. Results showed that <i>S. asper</i> consistently outperformed <i>S. oleraceus</i> across different light regimes and stress conditions. At a lower temperature regime of 15/5 °C, seed germination of <i>S. oleraceus</i> decreased by 19% compared to <i>S. asper</i>. Germination of <i>S. oleraceus</i> significantly declined under dark conditions, while over 90% of <i>S. asper</i> seeds germinated under both light/dark and dark conditions. Under water stress (osmotic potential of −0.4 MPa), <i>S. oleraceus</i> germination dropped by 74% compared to <i>S. asper</i>, indicating <i>S. asper</i>’s superior drought tolerance. Both species exhibited moderate salinity tolerance (40 mM NaCl) to germinate, highlighting their potential to invade saline cropping environments. The burial study revealed that <i>S. oleraceus</i> had higher germination at the soil surface, but no germination occurred from 4 cm, while 23% of <i>S. asper</i> seeds still emerged from that depth. The burial depth required to inhibit 50% emergence of <i>S. asper</i> and <i>S. oleraceus</i> was 3.3 cm and 0.3 cm, respectively. These findings highlight <i>S. asper</i>’s greater adaptability to low temperatures, burial depth, and stress conditions than <i>S. oleraceus</i>. The insights from this study can inform agronomic strategies, including tillage depth and mulching, to mitigate the impact of these invasive species on Australian cropping systems. |
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| ISSN: | 2223-7747 |