Aims

Seed germination is one of the most important processes in plant biology and ecology because it determines the timing and magnitude of seedling emergence events every growing season influencing community dynamics. Our aim was to determine whether polyethylene glycol (PEG) solutions simulate soil water potential accurately and recreate germination responses to soil water availability.

Methods

In this study, we compared seed germination of four plant species in PEG and four soils with different textures under six water potentials under controlled laboratory conditions.

Results

Total seed germination for all species significantly differed between soil and PEG under the same water potentials, as well as among soil water potentials for each of PEG and soil materials. Due to the inconsistent total germination associated with soil water potential, we evaluated unsaturated soil hydraulic conductivity (K_h) as a predictor of germination. The germination of all species followed the same response to K_h. Germination rate (GR₅₀) was more directly related to water potential than total germination, but K_h provided a more robust description of GR₅₀ across species and soils than PEG-osmotic potentials.

Conclusions

Our findings showed that K_h is a more informative variable to predict both total seed germination and germination rate in soil, and caution must be used when considering results obtained using PEG solutions to infer germination behavior under field conditions.

中文翻译：

---

种子发芽对土壤水力传导率和聚乙二醇（PEG）渗透溶液的响应

目的

种子发芽是植物生物学和生态学中最重要的过程之一，因为它决定了每个生长季节影响社区动态的幼苗出苗事件的时间和大小。我们的目标是确定聚乙二醇（PEG）解决方案是否能准确模拟土壤水势并重现对土壤水分有效性的萌发响应。

方法

在这项研究中，我们比较了在受控实验室条件下，在六种水势下，PEG和四种质地不同的土壤中四种植物物种的种子发芽情况。

结果

在相同的水势下，所有物种的总种子萌发在土壤和PEG之间以及在PEG和土壤物质各自的土壤水势之间都存在显着差异。由于与土壤水势相关的总发芽不一致，我们评估了非饱和土壤的水力传导率（K _h）作为发芽的预测因子。所有物种的发芽对K _h的反应相同。发芽率（GR ₅₀）与水势的关系比总发芽率更直接，但K _h比PEG渗透势更能可靠地描述物种和土壤中的GR ₅₀。

结论

我们的研究结果表明，K _h是预测土壤中总种子发芽和发芽率的信息量更大的变量，在考虑使用PEG溶液推断田间条件下的发芽行为时，必须谨慎行事。