Department of Plant Anatomy and Cytology, Faculty of Biology and Environmental Protection, University of Silesia in Katowice, 28 Jagiellonska Street, 40-032 Katowice, Poland.
Int J Mol Sci. 2018 Sep 25;19(10):2916. doi: 10.3390/ijms19102916.
Successful germination and seedling development are crucial steps in the growth of a new plant. In this study, we investigated the course of the cell cycle during germination in relation to grain hydration in the model grass (Brachypodium) for the first time. Flow cytometry was performed to monitor the cell cycle progression during germination and to estimate DNA content in embryo tissues. The analyses of whole zygotic embryos revealed that the relative DNA content was 2C, 4C, 8C, and 16C. Endoreplicated nuclei were detected in the scutellum and coleorhiza cells, whereas the rest of the embryo tissues only had nuclei with a 2C and 4C DNA content. This study was accompanied by a spatiotemporal profile analysis of the DNA synthetic activity in the organs of Brachypodium embryos during germination using EdU labelling. Upon imbibition, nuclear DNA replication was initiated in the radicle within 11 h and subsequently spread towards the plumule. The first EdU-labelled prophases were observed after 14 h of imbibition. Analysis of selected genes that are involved in the regulation of the cell cycle, such as those encoding cyclin-dependent kinases and cyclins, demonstrated an increase in their expression profiles.
成功的萌发和幼苗发育是新植物生长过程中的关键步骤。本研究首次调查了模式禾本科植物（柳枝稷）萌发过程中细胞周期与谷物水合作用的关系。通过流式细胞术监测萌发过程中的细胞周期进程，并估计胚胎组织中的 DNA 含量。对整个合子胚胎的分析表明，相对 DNA 含量分别为 2C、4C、8C 和 16C。在盾片和下胚轴细胞中检测到内复制核，而胚胎组织的其余部分仅具有 2C 和 4C DNA 含量的核。本研究还通过 EdU 标记对柳枝稷胚胎器官在萌发过程中的 DNA 合成活性进行了时空分布分析。在吸胀后 11 小时，根内开始进行核 DNA 复制，随后向芽延伸。在吸胀 14 小时后观察到第一批 EdU 标记的前期。对参与细胞周期调控的基因（如编码细胞周期蛋白依赖性激酶和细胞周期蛋白的基因）的分析表明，其表达谱增加。
