Figure 4
Ethylene production of climacteric tomato fruits previously treated with NOP-1 at different applications.
(a) Real-time monitoring of ethylene released by fruits treated with 200 μM NOP-1 (see insert for application form of the peptide) compared to untreated fruits and buffer control. Measurements were stopped when fruits showed a fully ripe phenotype. The initial burst in ethylene production within the first hours in fruits injected with the peptide is attributed to wounding. No reduction in ethylene production is evident in any of the different NOP-1 applications compared to buffer control or untreated fruits highlighting that ripening-delay caused by NOP-1 is not associated with lower levels in ethylene biosynthesis. The overall pattern of ethylene release is similar for all treatments, aside from the initial ethylene burst in the injected fruits and a peak shift in fruits incubated or injected with the peptide. (b) Average numbers of total ethylene release over 18 days in non-treated fruits (untreated and buffer control) compared to fruits treated with NOP-1 at different applications (surface-application, incubation and injection). In these calculations total ethylene release in injected fruits was corrected for the initial ethylene burst.
