Magnetization transfer and double-quantum filtered imaging as probes for motional restricted water in tulip bulbs

Parameter sensitive MRI experiments were performed on tulip bulbs before and after storage at two different temperatures, 4°C (chilled), and 20°C (non-chilled). Quantitative measurements of the amount of magnetization transfer (MT) in the storage scales of the bulbs, were compared to the average values of the relaxation rates R1 and R2, and the apparent normalized spin density (NSD). At the end of the storage period, bulbs were also scanned using 1H double quantum (DQ) filtered imaging. Both MT and DQ filtered imaging revealed significant differences between chilled and non-chilled bulbs, which were consistent with the differences observed in the average values of NSD, R1, and R2. The results indicated a smaller fraction of solid protons (e.g., starch, sugars, and possibly bound water), or less contact between these solid protons and (free) water in the storage scales of the chilled bulbs, after 8 weeks of storage at low temperature.