McCain D C, Markley J L
Biophys J. 1985 Nov;48(5):687-94. doi: 10.1016/S0006-3495(85)83826-1.
Some plant leaves display complex, orientation-dependent, proton nuclear magnetic resonance (1H NMR) spectra. The spectral patterns vary as the angle between the leaf surface and the applied magnetic field is varied. They also vary with temperature and with the quantity of absorbed manganous ions, but they are independent of magnetic field strength. In this paper, we propose a theory to explain the origin of the spectra and a model from which the patterns can be calculated. The theory shows how heterogeneous magnetic susceptibilities and local dipolar magnetic fields in chloroplasts can shift the water-proton resonance field. The model describes a simplified leaf structure in which the chloroplasts are nonrandomly aligned with respect to the leaf surface. Model calculations are tested by comparison with experimental spectra from hawthorn leaves (Crataegus sp.).
一些植物叶片呈现出复杂的、依赖于取向的质子核磁共振（1H NMR）光谱。当叶片表面与外加磁场之间的夹角变化时，光谱模式也会改变。它们还会随温度和吸收的锰离子数量而变化，但与磁场强度无关。在本文中，我们提出一种理论来解释光谱的起源，并提出一个可以计算光谱模式的模型。该理论展示了叶绿体中不均匀的磁化率和局部偶极磁场如何使水质子共振场发生偏移。该模型描述了一种简化的叶片结构，其中叶绿体相对于叶片表面呈非随机排列。通过与山楂叶（Crataegus sp.）的实验光谱进行比较，对模型计算进行了检验。
