A size-adjustable radiofrequency coil for investigating plants in a Halbach magnet.

A radio-frequency coil with adjustable distance has been developed and tested for in-situ examination of growing plants. The Helmholtz-based coil design reduces laborious tuning and matching efforts encountered with solenoids wound around a growing stem or branch. Relaxation experiments were performed on tomato plants and winter wheat under controlled light irradiation. Changes in signal amplitude and in relaxation times T were recorded over day and night cycles. Peaks in distributions of relaxation times were attributed to different tissue components of two different plants.