3.1.3. Relaxation times and proton density measurements
T2 and T1 relaxation time maps calculated from the set of MSE and TOMROP images are shown in Fig. 4. At the beginning of ripening, the contrast between different tissues was small, since the T2 values were similar. After 18 d of ripening, all the major regions observed in Fig. 1 could be distinguished, except the seeds. This demonstrated that the T2 change during ripening was tissuedependent. The tomato core can be distinguished fromthe placenta in the second and third images in Fig. 4A by careful observation, in contrast to the images of Fig. 1 in which the core did not appear. The T1 map on the first measurement day (Fig. 4B, day 1) did not allow any tissue discrimination.However discrimination becamepossible
on the second and third images (Fig. 4B, days 9 and 18), indicating
that the T1 of different tissues diverged as the fruit ripened.
The relaxation maps shown in Fig. 4 were used to extract mean
values of T2 and T1 of different tomato tissues on each experiment
day. The effects of fruit ripening on the relaxation times T2
and T1 measured in nine tomatoes in Experiment 1 are shown in
Fig. 5. The T2 and T1 of the core, placenta, radial and outer pericarp
decreased as the fruit ripened. Both T2 and T1 trends were consistent
among the tomatoes. Thiswas confirmed by the F-ratio, which
was always higher for the time effect than for the tomato sample
effect.
The ANOVA tests of the effects of ripening on T2