Germination is a high-risk phase in a plant’s life cycle and is directly regulated by temperature. Seeds germinate over a range of temperatures within which there is an optimum temperature, with thresholds above and below which no germination occurs. Rapid changes in temperature associated with global warming may cause a disconnect between temperatures a seed experiences and temperatures over which germination can occur. This paper explores the temperature dimension of the germination niche of eight herbaceous species from South West Western Australia as part of a broader assessment of endemic native species at risk of decline under global warming. The data obtained from germination studies on a temperature gradient plate were used to populate models to predict optimum germination responses (mean time to germination, germination timing and success) under current (1950–2000 averages) and future (2070 high greenhouse gas emission) temperature scenarios. The species exhibited a mix of germination responses, often with high tolerance to high diurnal temperatures. A number of species did not reach their full potential within the experimental period, indicating the presence of dormancy not overcome due to temperature alone. Modelling revealed that for some species the opportunity for germination may decline due to rising temperatures, but for others there would be little change, though a shift in germination timing may be expected. This approach to identifying extinction risk contributes tangibly to efforts to predict plant responses to environmental change and can help prioritize species for management actions, direct limited resources towards further investigations and supplement bioclimatic modelling.

中文翻译：

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温度对八种西澳大利亚草本植物萌发的影响

发芽是植物生命周期中的一个高风险阶段，直接受温度调节。种子在存在最佳温度的温度范围内发芽，阈值高于和低于该阈值不会发生发芽。与全球变暖相关的温度的快速变化可能导致种子经历的温度与发芽温度之间的脱节。本文探讨了来自西澳大利亚西南部的八种草本植物萌发生态位的温度维度，作为对在全球变暖下面临衰退风险的地方性本地物种进行更广泛评估的一部分。从温度梯度板上的发芽研究中获得的数据用于填充模型以预测最佳发芽反应（平均发芽时间，发芽时间和成功）在当前（1950-2000 年平均值）和未来（2070 年高温室气体排放）温度情景下。该物种表现出混合的萌发反应，通常对高昼夜温度具有很高的耐受性。许多物种在实验期间没有充分发挥其潜力，这表明休眠的存在并没有因为温度而被克服。建模显示，对于某些物种，由于温度升高，发芽机会可能会下降，但对于其他物种，几乎没有变化，尽管可能会发生发芽时间的变化。这种识别灭绝风险的方法对预测植物对环境变化的反应做出了切实的贡献，并有助于优先考虑物种的管理行动，