No abstract

A relatively recent technique termed comprehensive multiphase (CMP) NMR spectroscopy was used to investigate the growth and associated metabolomic changes of C-labeled wheat seeds and germinated seedlings. CMP-NMR enables the study of all phases in intact samples (i.e., liquid, gel-like, semisolid, and solid), by combining all required electronics into a single NMR probe, and can be used for investigating biological processes such as seed germination. All components, from the most liquid-like (i.e., dissolved metabolites) to the most rigid or solid-like (seed coat) were monitored in situ over 4 days. A wide range of metabolites were identified, and after 96 h of germination, the number of metabolites in the mobile phase more than doubled in comparison to 0 h (dry seed). This work represents the first application of CMP-NMR to follow biological processes in plants.

Seeds are complex entities composed of liquids, gels, and solids. NMR spectroscopy is a powerful tool for studying molecular structure but has evolved into two fields, solution and solid state. Comprehensive multiphase (CMP) NMR spectroscopy is capable of liquid-, gel-, and solid-state experiments for studying intact samples where all organic components are studied and differentiated in situ. Herein, intact (13)C-labeled seeds were studied by a variety of 1D/2D (1)H/(13)C experiments. In the mobile phase, an assortment of metabolites in a single (13)C-labeled wheat seed were identified; the gel phase was dominated by triacylglycerides; the semisolid phase was composed largely of carbohydrate biopolymers, and the solid phase was greatly influenced by starchy endosperm signals. Subsequently, the seeds were compared and relative similarities and differences between seed types discussed. This study represents the first application of CMP-NMR to food chemistry and demonstrates its general utility and feasibility for studying intact heterogeneous samples.