4. Discussion
In our study, tissue culture was used to control environmental
factors and reduce natural environmental variation. In vitro
cultured fruits were small in size (1−2 g); however, fruit ripening
patterns, such as coloration, were normal (Fig. 1A), and the growth
ratios were affected by salt stress (Fig. 1B). In addition, the percentage
DWofin vitro fruits was increased by salt stress under LL and HL,
similar to in vivo fruits (Fig. 2). Several studies have reported that
the percentage DW of tomato fruit is significantly increased by salt
stress because of reduced water accumulation (Bolarín et al., 2001;
Cuartero et al., 2006; Cuartero and Fernández-Munoz, ˜ 1998). Thus,
the in vitro fruits in our study could serve as a simplified experimental
system for studying the combined effects of salt stress and
light conditions while reducing natural environmental variation.