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首页> 外文期刊>Protoplasma: An International Journal of Cell Biology >QUANTITATIVE EVALUATION OF NMR AND MRI METHODS TO MEASURE SUCROSE CONCENTRATIONS IN PLANTS
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QUANTITATIVE EVALUATION OF NMR AND MRI METHODS TO MEASURE SUCROSE CONCENTRATIONS IN PLANTS

机译：NMR和MRI方法定量评估植物中蔗糖浓度的方法

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Developing pea (Pisum sativum L.) seeds were chosen to evaluate the performance of various nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) methods of detecting sucrose in plants. The methods included chemical shift selective imaging (CHESS), heteronuclear correlation via C-13-H-1 coupling (HMQC), and homonuclear correlation via H-1-H-1 coupling (DQF). The same experiments were also performed on sucrose phantom samples to evaluate the methods in the absence of the line broadening observed in plant systems. Using the spin echo technique for multi-slice imaging, we could discern the detailed internal structure of the intact seed with a resolution of tens of microns. The proton spin-lattice relaxation time and linewidth as a function of the age of the seed were measured to optimize the efficiency of the NMR and MR experiments. The age-dependent changes in these NMR parameters are consistent with the accumulation of insoluble starch as age increases. Both the NMR and MRI results are in accord with the results of chemical analysis, which reveal that the sucrose concentration is higher in the embryo than in the seed coat, and glucose is at low concentration throughout the seed. Of the three methods for proton observation, the enhanced version of the CHESS approach (CD-CHESS) provides the best combination of sucrose detection and water suppression. Direct observation of C-13 is preferable to indirect detection using HMQC because of water signal bleed-through in samples with large (>200 Hz) linewidths. [References: 36]
机译：选择发育中的豌豆（Pisum sativum L.）种子来评估检测植物中蔗糖的各种核磁共振（NMR）和磁共振成像（MRI）方法的性能。这些方法包括化学位移选择性成像（CHESS），通过C-13-H-1偶联（HMQC）的异核相关和通过H-1-H-1偶联（DQF）的同核相关。在蔗糖体模样品上也进行了相同的实验，以评估在植物系统中未观察到谱线展宽的情况下的方法。使用自旋回波技术进行多层成像，我们可以分辨出完整种子的详细内部结构，分辨率为数十微米。测量了质子自旋晶格弛豫时间和线宽随种子年龄的变化，以优化NMR和MR实验的效率。随着年龄的增长，这些NMR参数随年龄的变化与不溶性淀粉的积累是一致的。 NMR和MRI结果均与化学分析结果一致，这表明胚芽中的蔗糖浓度高于种皮，而整个种子中的葡萄糖浓度均较低。在三种质子观察方法中，增强版的CHESS方法（CD-CHESS）提供了蔗糖检测和水抑制的最佳组合。直接观察C-13优于使用HMQC进行间接检测，因为在大（> 200 Hz）线宽的样品中水信号会渗出。 [参考：36]

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