Germination Under Temperature Stress Facilitates Invasion in Indehiscent <i>Lepidium</i> Species
This study investigates the germination ecology of three <i>Lepidium</i> species, including the invasive, indehiscent-fruited <i>Lepidium appelianum</i> and <i>Lepidium draba</i>, and the invasive, dehiscent-fruited <i>Lepidium campestre</i>. The abili...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-05-01
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| Series: | Agriculture |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-0472/15/10/1078 |
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| Summary: | This study investigates the germination ecology of three <i>Lepidium</i> species, including the invasive, indehiscent-fruited <i>Lepidium appelianum</i> and <i>Lepidium draba</i>, and the invasive, dehiscent-fruited <i>Lepidium campestre</i>. The ability of <i>Lepidium</i> species to germinate under a wide range of temperature conditions is significant for understanding their potential invasiveness and establishment in novel and extreme environments. This study aims to clarify the germination behavior of <i>L. appelianum</i>, <i>L. draba</i>, and <i>L. campestre</i>, thereby enhancing our understanding of their invasive potential and ecological implications in the context of a changing climate. The base (Tb), optimum (To), and maximum temperatures for 50% germination (Tc(50)) were determined across a broad thermal gradient following standard protocols. Freshly harvested seeds and fruits of <i>L. appelianum</i> are non-dormant. In contrast, <i>L. draba</i> exhibit pericarp-mediated chemical dormancy, while <i>L. campestre</i> demonstrates physiological dormancy, which is released through after-ripening. The results indicate that <i>L. appelianum</i> and <i>L. draba</i> seeds and fruits germinate at a base temperature (Tb) of 1 °C and 4 °C, respectively. On the other hand, <i>L. campestre</i> seeds germinate at a Tb of 5.8 °C. The optimum temperature (To) for the germination of seeds and fruits in <i>L. appelianum</i> and <i>L. draba</i> ranges from 23 °C to 25 °C, while the To for <i>L. campestre</i> seed germination is 16 °C to 18 °C. Additionally, the maximum temperature for 50% germination (Tc(50)) for <i>L. appelianum</i> fruits is 39.8 °C, for <i>L. draba</i> it is 34.4 °C, and <i>L. campestre</i> reports a (Tc(50)) ranging from 27.4 °C to 33.3 °C for freshly harvested and after-ripened seeds, respectively. These results demonstrated that <i>L. appelianum</i> and <i>L. draba</i> can germinate across a broad temperature range, from very cold to very hot, unlike <i>L. campestre</i>. These findings suggest that the unique reproductive strategy of indehiscent fruits, coupled with a wide thermal germination niche, may contribute to the invasive success of <i>L. appelianum</i> and <i>L. draba</i>. Given the projected climate warming, the results highlight the potential for increased invasiveness of these species and suggest the need for targeted management strategies. |
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| ISSN: | 2077-0472 |