NMR Microscopy of Plants

Abstract

The first papers on the subject of NMR imaging were published in 1973.^(1,2) From the outset, the possibilities for the development of an NMR microscope were appreciated. Indeed, the seminal paper from the Mansfield⁽²⁾ group was entitled “NMR ‘diffraction’ in solids?” Clearly, a method along the lines of x-ray crystal diffraction was envisaged. The subsequent development of the subject, however, was entirely devoted to clinical ends, the first prototype whole-body imaging systems generating results in 1977–1978.^(3,4) Only within the last few years has attention returned to the development of a microscopic imaging system. Thus, in 1986 Aguayo et al. published NMR images of Xenopus laevis ova at various stages during oogenesis.⁽⁵⁾ The resolution obtained was 10 x 13 x 250 μm, and differences in the proton signal intensity from water were noted in the cell nucleus and the animal and vegetal poles of the cytoplasm. In the same year, Bone et al.⁽⁶⁾ reported an NMR microscopic study of the development of a domestic chicken embryo. A more modest resolution of 200 x 200 x 1250 μm was employed with their instrument, which was based on a 1.5 T whole-body imaging system. A three-dimensional imaging scheme was used. The same type of imaging system has been used to study changes in water distribution and binding in transpiring plants^(7,8) and water transport in plants with light-stressed foliage.⁽⁹⁾ The latter study involved observation of the root system in situ in the surrounding soil.