Song Yuan, Gao Xiaoye, Wu Yunjie
College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, China.
Karst Environmental Geological Hazard Prevention Laboratory of Guizhou Minzu University, Guiyang, China.
Front Plant Sci. 2021 Nov 22;12:767108. doi: 10.3389/fpls.2021.767108. eCollection 2021.
seeds have physiological dormancy. Cold stratification releases seed dormancy. The changes in metabolite profiles of dormant seeds and cold stratified seeds during shorter incubation time in a favorable condition for seed germination have been studied. However, a more-long-term detection of the changes in metabolites in dormant seeds can identify the real metabolic pathways responsible for dormancy. Metabolite composition was investigated in embryo and megagametophyte of primary physiological dormant seeds (DS) of collected at 0, 1, 2, 4, and 6 weeks of incubation and of non-primary physiological dormant seeds (NDS) sampled at 0 and 1 week of incubation, seed coat rupture stage, and radicle protrusion stage. Embryos contained higher levels of most metabolites than megagametophyte. Strong accumulation of most metabolites in DS occurred at 1 and 4 weeks of incubation. A larger reduction in the relative levels of most phosphorylated sugars and amino acids in NDS was found between 1-week-incubation and seed coat rupture stage. The relative levels of metabolites involved in carbohydrate metabolism, especially the pentose phosphate pathway (PPP) and tricarboxylic acid (TCA) cycle, were higher in the embryos of 4-week-incubated DS, but the relative contents of intermediate metabolites of most amino acid metabolism were lower compared to 1-week-incubated NDS. We suggested that the disturbed carbohydrate metabolism and amino acid metabolism in the embryos of DS after 4 weeks of incubation maybe related to primary dormancy. Our study provides information for a better understanding of the mechanism of seed dormancy.
种子具有生理休眠特性。低温层积可解除种子休眠。人们已经研究了在有利于种子萌发的条件下，休眠种子和低温层积种子在较短培养时间内代谢物谱的变化。然而，对休眠种子代谢物变化进行更长期的检测可以确定导致休眠的真正代谢途径。研究了在培养0、1、2、4和6周时收集的初级生理休眠种子（DS）以及在培养0和1周、种皮破裂阶段和胚根突出阶段采集的非初级生理休眠种子（NDS）的胚和雌配子体中的代谢物组成。胚中大多数代谢物的含量高于雌配子体。DS中大多数代谢物在培养1周和4周时大量积累。在培养1周和种皮破裂阶段之间，NDS中大多数磷酸化糖和氨基酸的相对水平有更大幅度的下降。参与碳水化合物代谢，尤其是磷酸戊糖途径（PPP）和三羧酸（TCA）循环的代谢物在培养4周的DS胚中的相对水平较高，但与培养1周的NDS相比，大多数氨基酸代谢中间产物的相对含量较低。我们认为，培养4周后DS胚中碳水化合物代谢和氨基酸代谢的紊乱可能与初级休眠有关。我们的研究为更好地理解种子休眠机制提供了信息。
