Abstract Different species have different germination strategies to cope with various climates they encounter when spreading, in which temperature and water are two of the most important factors that affect seed germination. Such differences in their coping strategies, therefore, could determine the fate of a species after its invasion into different environments. Cakile edentula is an invasive species originating from North America that invaded Australian coastlines. However, it has gradually disappeared in most of those habitats and can only be found in a few places nowadays. To explore whether germination strategy has had any contribution to such a phenomenon, we collected seeds from two populations with different climate patterns, i.e., subtropical and temperate. Germination experiments were performed using temperature and water potential hierarchies to detect differences of germination characteristics between the two populations. Based on the experimental data, a hydrothermal time model was utilized to further analyze and predict the germination characteristics of seeds from two populations. Results showed that germination percentage of C. edentula was affected by both temperature and water. The temperature and water requirements for germination of C. edentula varied significantly between populations. The population from the sub-tropical area displayed higher base water potential and base temperature for germination. However, there were a large fraction of seeds remaining dormancy, leading to a relatively low germination performance. Overall, our study has shown that C. edentula populations from subtropical and temperate climate zones differed in seed germination behavior, indicating its adaptation after invasion. Such results suggested that there was a wider environmental range than expected for seed germination in C. edentula, potentially promoting its invasion.

中文翻译：

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两种不同气候带的无花果（十字花科）种子萌发特性

摘要 不同的物种有不同的发芽策略来应对传播时遇到的各种气候，其中温度和水分是影响种子发芽的两个最重要的因素。因此，它们应对策略的这种差异可以决定一个物种入侵不同环境后的命运。Cakile edentula 是一种起源于北美的入侵物种，入侵了澳大利亚的海岸线。然而，它在大多数栖息地中逐渐消失，如今只能在少数地方找到。为了探讨发芽策略是否对这种现象有任何贡献，我们从具有不同气候模式的两个种群中收集了种子，即亚热带和温带。使用温度和水势层次进​​行发芽实验以检测两个种群之间发芽特征的差异。基于实验数据，利用热液时间模型进一步分析和预测两个种群种子的萌发特性。结果表明，C. edentula 的发芽率受温度和水的影响。C. edentula 发芽的温度和水需求在种群之间存在显着差异。来自亚热带地区的种群表现出较高的发芽基水势和基温。然而，有很大一部分种子处于休眠状态，导致发芽性能相对较低。总的来说，我们的研究表明，C. 来自亚热带和温带气候区的无齿蒿种群在种子萌发行为上存在差异，表明其在入侵后的适应性。这样的结果表明，在 C. edentula 中，种子萌发的环境范围比预期的要宽，这可能会促进其入侵。