Variation in carbohydrates and screening of related differential proteins during the seed germination of Magnolia sieboldii K. Koch

This paper focuses on carbohydrate metabolism of Magnolia sieboldii during seed germination by proteomics. 10 differentially accumulated proteins were found. Glycolysis is the most important metabolic pathways. Magnolia sieboldii K. Koch was selected as our research object. M. sieboldii seeds were initially soaked in clean water for 72 h and then stratified in wet sand with a seed-to-sand ratio of 1:3 at a fluctuating temperature. The relationship between carbohydrate metabolism and seed germination, and the localization of related proteins in metabolic pathways were investigated through seed embryo development, seed anatomical structure, carbohydrate change, and differentially accumulated protein analysis during seed stratification. On the basis of the results, we can divide seed dormancy and germination into three stages: unchanging embryo length (phase I), slow stretching phase (phase II), and rapid elongation phase (phase III). Two-dimensional electrophoresis revealed that 67 differentially accumulated proteins were obtained in four seed protein samples corresponding to the four key stages during the stratification of M. sieboldii seeds (0, 45, 90, and 110 days of stratification). Of the 67 differentially accumulated proteins, 7 were related to carbon metabolism and localized in 10 metabolic pathways and 4 were located in the glycolysis/gluconeogenesis pathway and upregulated in the early stage of seed germination, as indicated by KEGG metabolic pathway analysis. Thus, energy for seed germination was provided by glycolysis/gluconeogenesis in this stage.