The timing of the germination of seeds is highly responsive to inputs from the environment. Temperature plays a key role in the control of germination, with low temperatures acting to stimulate this developmental transition in many species. In Arabidopsis, extensive gene expression changes have been reported at the whole seed level in response to cold, while much less is known about their spatial distribution across the diverse cell types of the embryo. In this study we examined the spatiotemporal patterns of promoter activity and protein abundance for key gibberellic acid (GA) and abscisic acid (ABA) factors which regulate the decision to germinate both during a time course of germination and in response to cold. Low temperature stimulated the spatial relocalization of these factors to the vasculature. The response of these seeds to dormancy-breaking stratification treatments therefore stimulates the distribution of both positive (GA) and negatively acting (ABA) components to this same cell type. This altered spatial pattern persisted following the transfer of seeds to 22°C, as well as after their rehydration, indicating that this alteration is persistent. These observations suggest that the vasculature plays a role in the low temperature-mediated stimulation of germination in this species, while novel cell types are recruited to promote germination in response to stratification.

中文翻译：

---

低温刺激拟南芥种子萌发程序的空间分子重编程

种子发芽的时间对来自环境的输入高度敏感。温度在控制发芽方面起着关键作用，低温可刺激许多物种的这种发育转变。在拟南芥，据报道，在整个种子水平上响应寒冷的广泛基因表达变化，而对它们在胚胎不同细胞类型中的空间分布知之甚少。在这项研究中，我们检查了关键赤霉酸 (GA) 和脱落酸 (ABA) 因子的启动子活性和蛋白质丰度的时空模式，这些因子在发芽的时间过程中和对寒冷的反应中调节发芽的决定。低温刺激了这些因素在脉管系统中的空间重定位。因此，这些种子对打破休眠的分层处理的反应刺激了阳性 (GA) 和阴性 (ABA) 成分对同一细胞类型的分布。这种改变的空间模式在种子转移到 22°C 后持续存在，以及在补液后，表明这种变化是持久的。这些观察结果表明，脉管系统在该物种的低温介导的萌发刺激中起作用，而新的细胞类型被招募来促进萌发以响应分层。