- CHILLING INJURY IN TOMATO FRUIT 241
important to indicate whether induction or reduction of particular chill-
ing symptoms is ethylene dependent or not.
In summary, manifestation of chilling injury is a function of expo-
sure time by temperature. In short-term storage, injury processes are
reversible if the chilling stress is removed. However, if stress is main-
tained, ionic imbalances and/or loss of cellular integrity become exces-
sive and the process becomes irreversible. Afterward, removing the
stress or warming to non-chilling temperature only exacerbates injury
symptoms (Raison and Lyons 1986). By separating CI into two events,
it becomes possible to differentiate the primary “cause” (i.e., the initial
event happening upon chilling) from the secondary “effect” (i.e., the
subsequent events that produce physiological and visual signs of CI). It
helps to delineate the fundamental molecular mechanisms underlying
this phenomenon, which are enormously complex (Luengwilai et al.
2012).
III. CHILLING INJURY SYMPTOMS IN TOMATO
A storage temperature considered safe for mature-green tomato fruit
is 13◦C, whereas 7–10◦C is the threshold temperature for ripe toma-
toes (Suslow and Cantwell 1997). Chilling-induced quality changes in
tomatoes vary with cultivar (Abou-Aziz et al. 1974), duration of storage
(Hobson 1981), and fruit maturity (Autio and Bramlage 1986). Mature-
green tomatoes are usually more sensitive to low temperature than ripe
fruit (Hobson 1981) and sensitivity is reduced as fruit approach full
ripeness. Saltveit and Morris (1990), however, argued that ripe fruit may
appear more chilling-resistant simply because they cannot exhibit alter-
ations in the already accomplished process of ripening (i.e., red color
development). Genotype and preharvest growing conditions also influ-
ence chilling sensitivity in tomato (Saltveit 1991).
Cheng and Shewfelt (1988) reported that mature-green “Flora-Dade”
tomatoes stored at 4◦C showed a pronounced increase in decay after
15 d storage and irreversible inhibition of color development after 34 d.
Lurie and Klein (1992) found that field-grown “Rehovot 121” tomatoes
held at 2◦C for 21 d remained green and developed CI, whereas McDon-
ald et al. (1999) reported that only 14 d at that temperature resulted in
the inhibition of red color development in Florida-grown “Sunbeam”
tomatoes. Moline (1976) found that Florida-grown “Walter” tomatoes
stored at 2◦Cor7◦C for 10 d lost the capacity to convert chloroplasts
to chromoplasts and after 15 d fruit had swollen and had degenerated
mitochondria and plastids. Kader et al. (1978) suggested that a storage