Postharvest Biology and Technology of Fruits, Vegetables, and Flowers

230 POSTHARVEST BIOLOGY & TECHNOLOGY OF FRUITS, VEGETABLES, & FLOWERS
Ethylene concentration (ppm)
(a)
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
32.0
WT
10-3-B
10-6-C
8-2-E
Ethylene production
0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5
Respiration (CO 2 evolution)
CO2 concentration (ppm)
(b)
28.0
24.0
20.0
16.0
12.0
8.0
WT
10-3-B
10-6-C
8-2-E
0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5
Days after harvest (20°C)
Fig. 9.19 Patterns of (a) ethylene production and (b) CO 2 evolution (respiration) in fruit of wild type (WT)
and LePLDα2 antisense transgenic lines (10-3-B, 10-6-C, 8-2-E) of “Rutgers” tomato harvested at 40 days after
pollination (mature green stage in WT). Individual fruit of similar size and weight (6–8 per line) were sealed in
1-L jars connected to a flow through automated system that measured ethylene and CO 2 concentrations by gas
chromatography-flame ionization detection every 6 h for up to 9 days.
and the increase in respiratory CO 2 evolution associated with early stages of tomato ripening
were delayed in fruit of the three antisense lines, albeit to differing degrees (Fig. 9.19).
Fruits were harvested at 40 DAP, generally corresponding to late mature green stage in the
wild type. The delay in peak ethylene production was greatest for the antisense suppressed
line 10-6-C, and the maximum level of ethylene was lower in both 10-6-C and 8-2-E than in
10-3-B and wild type (Fig. 9.19a). Although the delay in ethylene production was similar
for lines 10-3-B and 8-2-E, fruit of the former showed an unusual rapid rise and decline,
peaking at about 5 days after harvest. It was evident that the wild-type fruit had already
begun the respiratory climacteric at harvest, whereas fruit of antisense lines 10-3-B, 10-6-C,
and 8-2-E entered the climacteric at successively later times during postharvest ripening
at 20 ◦ C (Fig. 9.19b). Maximum rates of CO 2 evolution were somewhat higher in fruit of