Literature references and germination trait values for different group of plant species

Germination is the first essential stage in crop and food production, as well as for the establishment of trees and regeneration of wild species. Temperature and water potential are the primary environmental factors that control germination in all species, and affect both the rate and final percentage germination. A comprehensive description of intra- and inter-variations between groups of species (perennials and annuals, trees, grasses, crops and wild species) helps understand where these species are currently able to grow on earth and will be in the future. By collecting germination trait data on 243 species from the literature and unpublished data, we provide a wide spectrum of species' seed germination traits, in the form of a set of parameter values describing germination responses to variations in temperature and water potential. Major differences in germination traits were seen to depend on the climatic conditions where the species grow or originated, with species able to germinate on ice and others unable to germinate below 18 °C. By contrast, within the different plant groups, similar ranges of threshold values were found, linked to the species geo-climatic origin. Crops however germinate faster, their range of threshold temperatures and water potential values is wider, and some crops have higher optimum and maximum temperatures as well as lower water potential threshold values. This is likely the result of human selection for rapid germination and for species able to grow in the wide range of environmental conditions where agriculture was developed. Our analyses revealed correlation between traits: negative correlations appeared between germination speed and temperature thresholds, and between temperature and water potential thresholds. The collected data also form a valuable database, enabling plant establishment to be better taken into account in modeling and simulation studies of vegetation boundaries (wild or cultivated) under changing land-use and climate.种子萌发（germination）是作物与粮食生产、树木定植以及野生物种自然更新的首要关键阶段。温度（temperature）与水势（water potential）是调控所有物种种子萌发的核心环境因子，同时影响萌发速率与最终萌发率。全面解析不同物种类群（多年生与一年生植物、树木、草本、作物及野生物种）内部及类群间的萌发性状变异，有助于明确当前及未来这些物种在全球的适生分布范围。本研究通过收集243个物种的已发表文献与未公开萌发性状数据，以一系列参数值的形式呈现了各物种种子萌发对温度与水势变化的响应特征，涵盖了广泛的物种类群萌发性状谱。研究发现萌发性状的显著差异与物种生长或起源的气候条件密切相关：部分物种可在结冰环境下萌发，而另一些物种则无法在18℃以下完成萌发。相较而言，同一植物类群内部则呈现出相似的阈值（threshold value）区间，该特征与物种的地理气候起源相关。但作物的萌发速率更快，其温度与水势阈值区间更广，部分作物还拥有更高的最适温度（optimum temperature）与最高温度（maximum temperature），以及更低的水势阈值。这一现象大概率是人类为选育快速萌发物种，以及适配农业发展所需多样环境条件的物种而进行人工选择的结果。本研究的分析还揭示了性状间的关联：萌发速率与温度阈值之间、温度阈值与水势阈值之间均呈现负相关关系。本研究收集的数据集亦构建了一份极具价值的数据库，可帮助在土地利用与气候变化背景下，开展野生或栽培植被边界的建模与模拟研究时，更好地纳入植物定植相关因素。