NMR MICROSCOPY OF THE GERMINATING CASTOR BEAN

Water uptake is the trigger for germination and growth. It is a trisphasic process, involving a rapid rehydration of the endosperm, a steady uptake during a period of active metabolism and finally, a rapid uptake during development of the root system. The water spin lattice relaxation time (T1) of the germinating seed of the castor bean (Ricinus communis zanzibariensis) apparently decreases with increasing water content. This anomalous behaviour is resolved when the recovery process is analysed as two components: each component shows the expected dependence on water content but the proportion of the faster relaxing component increase during development. NMR microscopy is used to investigate the location of these water compartments and to follow the anatomical changes which occur during the germination and early growth processes.