NMR imaging shows water distribution and transport in plant root systems in situ

Images of Vicia faba L. root systems at 0.6-mm resolution, undisturbed and within the soil medium in which they were grown, have been obtained by using a 1.5-Tesla proton ((1)H) NMR medical imaging research system. Images of root systems in seven soil media (Cahaba soil, vermiculite, sand, perlite, fritted clay, potting soil, and peatlite) exhibited variable but useful quality owing to a diversity of magnetic properties of the soils. Root structure and pathology in the form of partial decay of hypogeal cotyledons were easily discernible. Water transport in roots with light-stressed foliage was demonstrated by using water doped with a paramagnetic NMR contrast agent, and the process of plant-wilt and recovery was monitored in situ. Images of germinated seeds within soil media indicated that dynamic observations of germination and growth are possible. The results suggest that NMR imaging can be an effective noninvasive tool for studying plants in situ.